Sorting with a hash table

 

We only need to create the Table ADT and insert data
(words) into it. No other manipulations are needed.
But I'm just lost as to how to do this. Do I insert
the words into a linked list? If so, what am I
supposed to do after I've inserted everything into a
LL..Ok, you're only mimicking the behavior.
Create a class named MyTable:public class MyTable {
    private LinkedList words;
    public MyTable() {
        // your code
    public void insert(String word) {
        // your code
    // other methods
}This class holds, as you can see, a LinkedList which you will be filling with WordOccurrence objects. A WordOccurrence object will look like this:public class WordOccurrence {
    private String word;
    private int occurrence;
    public WordOccurrence(String word) {
        // your code
    // the rest of your methods here
}Before your insert something in your MyTable class, just check your LinkedList if the word is already in it, if it is, increate the occurrence with one.
Good luck.

Similar Messages

  • Problems with a hash table

    hi, i have a CountryTable class which i want to implement as a hash table:
    import java.util.*;
    class CountryTable {
         static int count = 0;
         private HashMap table = new HashMap();
         public void addEntry(Colour key, Country country) {
              table.put(key, country);
              count++;
         public Country getCountry(Colour key) {
              return (Country)table.get(key);
         static int getCount() {
              return count;
    The object which are returned from this table is Country:
    class Country {
         //static variables
         static int count = 0;
         //instance variables
         private String name;
         private Colour base;
         //constructor
         Country(String name, Colour base) {
              this.name = name;
              this.base = base;
              count++;
         //return the number of objects created
         static int getCount() {
              return count;
         //return the name
         public String getName() {
              return name;
         public Colour getColour() {
              return base;
    The key for the has table is the class Colour, which includes a hashCode() method:
    class Colour {
         public int rgb;
         Colour(int rgb) {
              this.rgb = rgb;
         public int hashCode() {
              return rgb * -1;
    I implement these classes in a program as follows:
    CountryTable index = new CountryTable();
              Colour colour1 = new Colour(-3473408);
              Country argentina = new Country("Argentina", colour1);
              index.addEntry(colour1, argentina);
              Colour colour2 = new Colour(-131072);
              Country brazil = new Country("Brazil", colour2);
              index.addEntry(colour2, brazil);
                        Colour col = new Colour(or);
                        Country coun = index.getCountry(col);
                        System.out.println(coun.getName());
    I have a list of many countries which i set up, with their relevant countires with which they are associated.
    The variable 'or' contains an RGB value which has been returned elsewhere in the program. The problem that i have is that when a colour is passed into the getCountry() method, nothing is returned and a "nullPointerException" is thrown, even though a colour with which i set up a country was passed in???
    Anyone got any ideas where im going wrong?
    Many thanks Cath

    keeping the other two files same you change the CountryTable to this
    import java.util.*;
    class CountryTable {
    static int count = 0;
    private HashMap table = new HashMap();
    public void addEntry(Colour key, Country country) {
    table.put(key.rgb+"" ,country.getName());
    count++;
    public String getCountry(Colour key) {
    return (String)table.get(key.rgb+"");
    static int getCount() {
    return count;
    public static void main (String args[]){
         CountryTable index = new CountryTable();
    Colour colour1 = new Colour(-3473408);
    Country argentina = new Country("Argentina",colour1);
    index.addEntry(colour1, argentina);
    Colour colour2 = new Colour(-131072);
    Country brazil = new Country("Brazil",colour2);
    index.addEntry(colour2, brazil);
    System.out.println(index.table);
    String coun = index.getCountry(colour2);
    System.out.println(coun);
    }and now try

  • Experimenting with hashed table.

    Hello experts,
    I am currently experementing with using hashed table for my report and this is my first time to try this. Below is my code:
    DATA: it_iloa  type hashed TABLE OF t_iloa
           WITH unique KEY iloan.
    Now here is my problem, Originally I am reading it_iloa using its header line. Now, how can I define my hashed table to have a work area/header line?
    Again, thanks guys and have a nice day!

    Hi,
    The SORTED table / HASH table are best used along with a LEY definition of the table, meaning you will declare a key for the internal table.
    So, while declare the table add the WITH UNIQUE KEY column1.
    This will create a HASH index on the column1 and when you are reading the table, make sure you have column1 in the where clause so that HASH index is used and the performance is improved.
    However, unless the table has got huge data you will not be able to see the difference.
    Regards,
    Ravi

  • SORTED & HASHED tables

    Hi all
         what exactly are the SORTED & HASHED tables??
    Regards
    Srini

    Internal tables are the core of ABAP. They are like soul of a body. For any program we use
    internal tables extensively. We can use Internal tables like normal data base tables only, but the
    basic difference is the memory allocated for internal tables is temporary. Once the program is
    closed the memory allocated for internal tables will also be out of memory.
    But while using the internal tables, there are many performance issues to be considered. i.e which
    type of internal table to be used for the program..like standard internal table, hashed internal
    table or sorted internal table etc..
    Internal tables
    Internal tables provide a means of taking data from a fixed structure and storing it in working memory in ABAP. The data is stored line by
    line in memory, and each line has the same structure. In ABAP, internal tables fulfill the function of arrays. Since they are dynamic data
    objects, they save the programmer the task of dynamic memory management in his or her programs. You should use internal tables
    whenever you want to process a dataset with a fixed structure within a program. A particularly important use for internal tables is for
    storing and formatting data from a database table within a program. They are also a good way of including very complicated data
    structures in an ABAP program.
    Like all elements in the ABAP type concept, internal tables can exist both as data types and as data objects A data type is the abstract
    description of an internal table, either in a program or centrally in the ABAP Dictionary, that you use to create a concrete data object. The
    data type is also an attribute of an existing data object.
    Internal Tables as Data Types
    Internal tables and structures are the two structured data types in ABAP. The data type of an internal table is fully specified by its line type,
    key, and table type.
    Line type
    The line type of an internal table can be any data type. The data type of an internal table is normally a structure. Each component of the
    structure is a column in the internal table. However, the line type may also be elementary or another internal table.
    Key
    The key identifies table rows. There are two kinds of key for internal tables - the standard key and a user-defined key. You can specify
    whether the key should be UNIQUE or NON-UNIQUE. Internal tables with a unique key cannot contain duplicate entries. The uniqueness
    depends on the table access method.
    If a table has a structured line type, its default key consists of all of its non-numerical columns that are not references or themselves
    internal tables. If a table has an elementary line type, the default key is the entire line. The default key of an internal table whose line type
    is an internal table, the default key is empty.
    The user-defined key can contain any columns of the internal table that are not references or themselves internal tables. Internal tables
    with a user-defined key are called key tables. When you define the key, the sequence of the key fields is significant. You should remember
    this, for example, if you intend to sort the table according to the key.
    Table type
    The table type determines how ABAP will access individual table entries. Internal tables can be divided into three types:
    Standard tables have an internal linear index. From a particular size upwards, the indexes of internal tables are administered as trees. In
    this case, the index administration overhead increases in logarithmic and not linear relation to the number of lines. The system can access
    records either by using the table index or the key. The response time for key access is proportional to the number of entries in the table.
    The key of a standard table is always non-unique. You cannot specify a unique key. This means that standard tables can always be filled
    very quickly, since the system does not have to check whether there are already existing entries.
    Sorted tables are always saved sorted by the key. They also have an internal index. The system can access records either by using the
    table index or the key. The response time for key access is logarithmically proportional to the number of table entries, since the system
    uses a binary search. The key of a sorted table can be either unique or non-unique. When you define the table, you must specify whether
    the key is to be unique or not. Standard tables and sorted tables are known generically as index tables.
    Hashed tables have no linear index. You can only access a hashed table using its key. The response time is independent of the number of
    table entries, and is constant, since the system access the table entries using a hash algorithm. The key of a hashed table must be unique.
    When you define the table, you must specify the key as UNIQUE.
    Generic Internal Tables
    Unlike other local data types in programs, you do not have to specify the data type of an internal table fully. Instead, you can specify a
    generic construction, that is, the key or key and line type of an internal table data type may remain unspecified. You can use generic
    internal tables to specify the types of field symbols and the interface parameters of procedures . You cannot use them to declare data
    objects.
    Internal Tables as Dynamic Data Objects
    Data objects that are defined either with the data type of an internal table, or directly as an internal table, are always fully defined in
    respect of their line type, key and access method. However, the number of lines is not fixed. Thus internal tables are dynamic data objects,
    since they can contain any number of lines of a particular type. The only restriction on the number of lines an internal table may contain are
    the limits of your system installation. The maximum memory that can be occupied by an internal table (including its internal administration)
    is 2 gigabytes. A more realistic figure is up to 500 megabytes. An additional restriction for hashed tables is that they may not contain more
    than 2 million entries. The line types of internal tables can be any ABAP data types - elementary, structured, or internal tables. The
    individual lines of an internal table are called table lines or table entries. Each component of a structured line is called a column in the
    internal table.
    Choosing a Table Type
    The table type (and particularly the access method) that you will use depends on how the typical internal table operations will be most
    frequently executed.
    Standard tables
    This is the most appropriate type if you are going to address the individual table entries using the index. Index access is the quickest
    possible access. You should fill a standard table by appending lines (ABAP APPEND statement), and read, modify and delete entries by
    specifying the index (INDEX option with the relevant ABAP command). The access time for a standard table increases in a linear relationship
    with the number of table entries. If you need key access, standard tables are particularly useful if you can fill and process the table in
    separate steps. For example, you could fill the table by appending entries, and then sort it. If you use the binary search option with key
    access, the response time is logarithmically proportional to the number of table entries.
    Sorted tables
    This is the most appropriate type if you need a table which is sorted as you fill it. You fill sorted tables using the INSERT statement. Entries
    are inserted according to the sort sequence defined through the table key. Any illegal entries are recognized as soon as you try to add
    them to the table. The response time for key access is logarithmically proportional to the number of table entries, since the system always
    uses a binary search. Sorted tables are particularly useful for partially sequential processing in a LOOP if you specify the beginning of the
    table key in the WHERE condition.
    Hashed tables
    This is the most appropriate type for any table where the main operation is key access. You cannot access a hashed table using its index.
    The response time for key access remains constant, regardless of the number of table entries. Like database tables, hashed tables always
    have a unique key. Hashed tables are useful if you want to construct and use an internal table which resembles a database table or for
    processing large amounts of data.
    Creating Internal Tables
    Like other elements in the ABAP type concept, you can declare internal tables as abstract data
    types in programs or in the ABAP Dictionary, and then use them to define data objects.
    Alternatively, you can define them directly as data objects. When you create an internal table as a
    data object, you should ensure that only the administration entry which belongs to an internal
    table is declared statically. The minimum size of an internal table is 256 bytes. This is important if an
    internal table occurs as a component of an aggregated data object, since even empty internal
    tables within tables can lead to high memory usage. (In the next functional release, the size of the
    table header for an initial table will be reduced to 8 bytes). Unlike all other ABAP data objects, you
    do not have to specify the memory required for an internal table. Table rows are added to and
    deleted from the table dynamically at runtime by the various statements for adding and deleting
    records.
    You can create internal tables in different types.
    You can create standard internal table and then make it sort in side the program.
    The same way you can change to hashed internal tables also.
    There will be some performance issues with regard to standard internal tables/ hashed internal
    tables/ sorted internal tables.
    Internal table types
    This section describes how to define internal tables locally in a program. You can also define internal tables globally as data types in the
    ABAP Dictionary.
    Like all local data types in programs , you define internal tables using the TYPES statement. If you do not refer to an existing table type
    using the TYPE or LIKE addition, you can use the TYPES statement to construct a new local internal table in your program.
    TYPES <t> TYPE|LIKE <tabkind> OF <linetype> [WITH <key>]
    [INITIAL SIZE <n>].
    After TYPE or LIKE, there is no reference to an existing data type. Instead, the type constructor occurs:
    <tabkind> OF <linetype> [WITH <key>]
    The type constructor defines the table type <tabkind>, the line type <linetype>, and the key <key> of the internal table <t>.
    You can, if you wish, allocate an initial amount of memory to the internal table using the INITIAL SIZE addition.
    Table type
    You can specify the table type <tabkind> as follows:
    Generic table types
    INDEX TABLE
    For creating a generic table type with index access.
    ANY TABLE
    For creating a fully-generic table type.
    Data types defined using generic types can currently only be used for field symbols and for interface parameters in procedures . The generic
    type INDEX TABLE includes standard tables and sorted tables. These are the two table types for which index access is allowed. You cannot
    pass hashed tables to field symbols or interface parameters defined in this way. The generic type ANY TABLE can represent any table. You
    can pass tables of all three types to field symbols and interface parameters defined in this way. However, these field symbols and
    parameters will then only allow operations that are possible for all tables, that is, index operations are not allowed.
    Fully-Specified Table Types
    STANDARD TABLE or TABLE
    For creating standard tables.
    <b>SORTED TABLE</b>
    For creating sorted tables.
    <b>HASHED TABLE</b>
    For creating hashed tables.
    Fully-specified table types determine how the system will access the entries in the table in key operations. It uses a linear search for
    standard tables, a binary search for sorted tables, and a search using a hash algorithm for hashed tables.
    Line type
    For the line type <linetype>, you can specify:
    Any data type if you are using the TYPE addition. This can be a predefined ABAP type, a local type in the program, or a data type from the
    ABAP Dictionary. If you specify any of the generic elementary types C, N, P, or X, any attributes that you fail to specify (field length, number
    of decimal places) are automatically filled with the default values. You cannot specify any other generic types.
    Any data object recognized within the program at that point if you are using the LIKE addition. The line type adopts the fully-specified data
    type of the data object to which you refer. Except for within classes, you can still use the LIKE addition to refer to database tables and
    structures in the ABAP Dictionary (for compatibility reasons).
    All of the lines in the internal table have the fully-specified technical attributes of the specified data type.
    Key
    You can specify the key <key> of an internal table as follows:
    [UNIQUE|NON-UNIQUE] KEY <col1> ... <col n>
    In tables with a structured line type, all of the components <coli> belong to the key as long as they are not internal tables or references,
    and do not contain internal tables or references. Key fields can be nested structures. The substructures are expanded component by
    component when you access the table using the key. The system follows the sequence of the key fields.
    [UNIQUE|NON-UNIQUE] KEY TABLE LINE
    If a table has an elementary line type (C, D, F, I, N, P, T, X), you can define the entire line as the key. If you try this for a table whose line
    type is itself a table, a syntax error occurs. If a table has a structured line type, it is possible to specify the entire line as the key. However,
    you should remember that this is often not suitable.
    [UNIQUE|NON-UNIQUE] DEFAULT KEY
    This declares the fields of the default key as the key fields. If the table has a structured line type, the default key contains all non-numeric
    columns of the internal table that are not and do not contain references or internal tables. If the table has an elementary line type, the
    default key is the entire line. The default key of an internal table whose line type is an internal table, the default key is empty.
    Specifying a key is optional. If you do not specify a key, the system defines a table type with an arbitrary key. You can only use this to
    define the types of field symbols and the interface parameters of procedures . For exceptions, refer to Special Features of Standard Tables.
    The optional additions UNIQUE or NON-UNIQUE determine whether the key is to be unique or non-unique, that is, whether the table can
    accept duplicate entries. If you do not specify UNIQUE or NON-UNIQUE for the key, the table type is generic in this respect. As such, it can
    only be used for specifying types. When you specify the table type simultaneously, you must note the following restrictions:
    You cannot use the UNIQUE addition for standard tables. The system always generates the NON-UNIQUE addition automatically.
    You must always specify the UNIQUE option when you create a hashed table.
    Initial Memory Requirement
    You can specify the initial amount of main memory assigned to an internal table object when you define the data type using the following
    addition:
    INITIAL SIZE <n>
    This size does not belong to the data type of the internal table, and does not affect the type check. You can use the above addition to
    reserve memory space for <n> table lines when you declare the table object.
    When this initial area is full, the system makes twice as much extra space available up to a limit of 8KB. Further memory areas of 12KB each
    are then allocated.
    You can usually leave it to the system to work out the initial memory requirement. The first time you fill the table, little memory is used. The
    space occupied, depending on the line width, is 16 <= <n> <= 100.
    It only makes sense to specify a concrete value of <n> if you can specify a precise number of table entries when you create the table and
    need to allocate exactly that amount of memory (exception: Appending table lines to ranked lists). This can be particularly important for
    deep-structured internal tables where the inner table only has a few entries (less than 5, for example).
    To avoid excessive requests for memory, large values of <n> are treated as follows: The largest possible value of <n> is 8KB divided by the
    length of the line. If you specify a larger value of <n>, the system calculates a new value so that n times the line width is around 12KB.
    Examples
    TYPES: BEGIN OF LINE,
    COLUMN1 TYPE I,
    COLUMN2 TYPE I,
    COLUMN3 TYPE I,
    END OF LINE.
    TYPES ITAB TYPE SORTED TABLE OF LINE WITH UNIQUE KEY COLUMN1.
    The program defines a table type ITAB. It is a sorted table, with line type of the structure LINE and a unique key of the component
    COLUMN1.
    TYPES VECTOR TYPE HASHED TABLE OF I WITH UNIQUE KEY TABLE LINE.
    TYPES: BEGIN OF LINE,
    COLUMN1 TYPE I,
    COLUMN2 TYPE I,
    COLUMN3 TYPE I,
    END OF LINE.
    TYPES ITAB TYPE SORTED TABLE OF LINE WITH UNIQUE KEY COLUMN1.
    TYPES: BEGIN OF DEEPLINE,
    FIELD TYPE C,
    TABLE1 TYPE VECTOR,
    TABLE2 TYPE ITAB,
    END OF DEEPLINE.
    TYPES DEEPTABLE TYPE STANDARD TABLE OF DEEPLINE
    WITH DEFAULT KEY.
    The program defines a table type VECTOR with type hashed table, the elementary line type I and a unique key of the entire table line. The
    second table type is the same as in the previous example. The structure DEEPLINE contains the internal table as a component. The table
    type DEEPTABLE has the line type DEEPLINE. Therefore, the elements of this internal table are themselves internal tables. The key is the
    default key - in this case the column FIELD. The key is non-unique, since the table is a standard table.
    Internal table objects
    Internal tables are dynamic variable data objects. Like all variables, you declare them using the DATA statement. You can also declare static
    internal tables in procedures using the STATICS statement, and static internal tables in classes using the CLASS-DATA statement. This
    description is restricted to the DATA statement. However, it applies equally to the STATICS and CLASS-DATA statements.
    Reference to Declared Internal Table Types
    Like all other data objects, you can declare internal table objects using the LIKE or TYPE addition of the DATA statement.
    DATA <itab> TYPE <type>|LIKE <obj> [WITH HEADER LINE].
    Here, the LIKE addition refers to an existing table object in the same program. The TYPE addition can refer to an internal type in the
    program declared using the TYPES statement, or a table type in the ABAP Dictionary.
    You must ensure that you only refer to tables that are fully typed. Referring to generic table types (ANY TABLE, INDEX TABLE) or not
    specifying the key fully is not allowed (for exceptions, refer to Special Features of Standard Tables).
    The optional addition WITH HEADER line declares an extra data object with the same name and line type as the internal table. This data
    object is known as the header line of the internal table. You use it as a work area when working with the internal table (see Using the
    Header Line as a Work Area). When you use internal tables with header lines, you must remember that the header line and the body of the
    table have the same name. If you have an internal table with header line and you want to address the body of the table, you must indicate
    this by placing brackets after the table name (<itab>[]). Otherwise, ABAP interprets the name as the name of the header line and not of the
    body of the table. You can avoid this potential confusion by using internal tables without header lines. In particular, internal tables nested
    in structures or other internal tables must not have a header line, since this can lead to ambiguous expressions.
    TYPES VECTOR TYPE SORTED TABLE OF I WITH UNIQUE KEY TABLE LINE.
    DATA: ITAB TYPE VECTOR,
    JTAB LIKE ITAB WITH HEADER LINE.
    MOVE ITAB TO JTAB. <- Syntax error!
    MOVE ITAB TO JTAB[].
    The table object ITAB is created with reference to the table type VECTOR. The table object JTAB has the same data type as ITAB. JTAB also
    has a header line. In the first MOVE statement, JTAB addresses the header line. Since this has the data type I, and the table type of ITAB
    cannot be converted into an elementary type, the MOVE statement causes a syntax error. The second MOVE statement is correct, since
    both operands are table objects.
    Declaring New Internal Tables
    You can use the DATA statement to construct new internal tables as well as using the LIKE or TYPE addition to refer to existing types or
    objects. The table type that you construct does not exist in its own right; instead, it is only an attribute of the table object. You can refer to
    it using the LIKE addition, but not using TYPE. The syntax for constructing a table object in the DATA statement is similar to that for defining
    a table type in the TYPES statement.
    DATA <itab> TYPE|LIKE <tabkind> OF <linetype> WITH <key>
    [INITIAL SIZE <n>]
    [WITH HEADER LINE].
    As when you define a table type , the type constructor
    <tabkind> OF <linetype> WITH <key>
    defines the table type <tabkind>, the line type <linekind>, and the key <key> of the internal table <itab>. Since the technical attributes of
    data objects are always fully specified, the table must be fully specified in the DATA statement. You cannot create generic table types (ANY
    TABLE, INDEX TABLE), only fully-typed tables (STANDARD TABLE, SORTED TABLE, HASHED TABLE). You must also specify the key and whether
    it is to be unique (for exceptions, refer to Special Features of Standard Tables).
    As in the TYPES statement, you can, if you wish, allocate an initial amount of memory to the internal table using the INITIAL SIZE addition.
    You can create an internal table with a header line using the WITH HEADER LINE addition. The header line is created under the same
    conditions as apply when you refer to an existing table type.
    DATA ITAB TYPE HASHED TABLE OF SPFLI
    WITH UNIQUE KEY CARRID CONNID.
    The table object ITAB has the type hashed table, a line type corresponding to the flat structure SPFLI from the ABAP Dictionary, and a
    unique key with the key fields CARRID and CONNID. The internal table ITAB can be regarded as an internal template for the database table
    SPFLI. It is therefore particularly suitable for working with data from this database table as long as you only access it using the key.

  • Hash tables in combination with data references to the line type.

    I'm having an issue with hash tables - in combination with reference variables.
    Consider the following:  (Which is part of a class)  -  it attempts to see if a particular id exists in a table; if not add it; if yes change it.   
      types: BEGIN OF TY_MEASUREMENT,
               perfid      TYPE zgz_perf_metric_id,
               rtime       TYPE zgz_perf_runtime,
               execount    TYPE zgz_perf_execount,
               last_start  TYPE timestampl,
             END OF TY_MEASUREMENT.
    METHOD START.
      DATA:  ls_measurement TYPE REF TO ty_measurement.
      READ TABLE gt_measurements WITH TABLE KEY perfid = i_perfid reference into ls_measurement.
      if sy-subrc <> 0.
        "Didn't find it.
        create data ls_measurement.
        ls_measurement->perfid = i_perfid.
        insert ls_measurement->* into gt_measurements.
      endif.
      GET TIME STAMP FIELD ls_measurements-last_start.
      ls_measurement->execount = ls_measurement->execount + 1.
    ENDMETHOD.
    I get compile errors on the insert statement - either "You cannot use explicit index operations on tables with types HASHED TABLE" or "ANY TABLE".      It is possible that.
    If I don't dereference the type then I get the error  LS_MEASUREMENT cannot be converted to the line type of GT_MEASUREMENTS.
    I'm not looking to solve this with a combination of references and work ares - want a reference solution.   
    Thanks!
    _Ryan
    Moderator message - Moved to the correct forum
    Edited by: Rob Burbank on Apr 22, 2010 4:43 PM

    I think it might work when you change it for
    insert ls_measurement->* into TABLE gt_measurements.
    For hashed table a new line here will be inserted according to given table key.
    Regards
    Marcin

  • ABAP hash table

    Hi Guys,
    I have an internal table with employee name and its attributes, like address, family etc. Each employee can have multiple records in the table.
    I want to create a table of tables with key as employee ID and rest of the employee attributes inside the table.
    So each employee then will have one row in the main table and all its attributes will be in the inner table.
    Can someone please share a sample code to achieve this?
    Regards,
    ~Mark

    Hi,
    Hashed tables
    This is the most appropriate type for any table where the main operation is key access. You cannot access a hashed table using its index. The response time for key access remains
    constant, regardless of the number of table entries. Like database tables, hashed tables always have a unique key. Hashed tables are useful if you want to construct and use an internal table which resembles a database table or for processing large amounts of data.
    Example:
    TYPES VECTOR TYPE HASHED TABLE OF I WITH UNIQUE KEY TABLE
    LINE.
    TYPES: BEGIN OF LINE,
    COLUMN1 TYPE I,
    COLUMN2 TYPE I,
    COLUMN3 TYPE I,
    END OF LINE.
    TYPES ITAB TYPE SORTED TABLE OF LINE WITH UNIQUE KEY COLUMN1.
    TYPES: BEGIN OF DEEPLINE,
    FIELD TYPE C,
    TABLE1 TYPE VECTOR,
    TABLE2 TYPE ITAB,
    END OF DEEPLINE.
    TYPES DEEPTABLE TYPE STANDARD TABLE OF DEEPLINE
    WITH DEFAULT KEY.
    The program defines a table type VECTOR with type hashed table, the elementary line type I and a unique key of the entire table line. The second table type is the same as in the previous example. The structure DEEPLINE contains the internal table as a component. The table type DEEPTABLE has the line type DEEPLINE. Therefore, the elements of this internal table are themselves internal tables. The key is the default key - in this case the column FIELD. The key is non-unique, since the table is a standard table.
    Regards,
    Bhaskar

  • Standard & hashed tables

    hello every one,
    This is rahul
    when we are declaring internal table by default it takes as standard  table
    but y don't we take hashed table they can get performance very well
    hashed can perform very well than standard na

    hI
    READ THIS POINTS
    Internal tables are the core of ABAP. They are like soul of a body. For any program we use
    internal tables extensively. We can use Internal tables like normal data base tables only, but the
    basic difference is the memory allocated for internal tables is temporary. Once the program is
    closed the memory allocated for internal tables will also be out of memory.
    But while using the internal tables, there are many performance issues to be considered. i.e which
    type of internal table to be used for the program..like standard internal table, hashed internal
    table or sorted internal table etc..
    Internal tables
    Internal tables provide a means of taking data from a fixed structure and storing it in working memory in ABAP. The data is stored line by
    line in memory, and each line has the same structure. In ABAP, internal tables fulfill the function of arrays. Since they are dynamic data
    objects, they save the programmer the task of dynamic memory management in his or her programs. You should use internal tables
    whenever you want to process a dataset with a fixed structure within a program. A particularly important use for internal tables is for
    storing and formatting data from a database table within a program. They are also a good way of including very complicated data
    structures in an ABAP program.
    Like all elements in the ABAP type concept, internal tables can exist both as data types and as data objects A data type is the abstract
    description of an internal table, either in a program or centrally in the ABAP Dictionary, that you use to create a concrete data object. The
    data type is also an attribute of an existing data object.
    Internal Tables as Data Types
    Internal tables and structures are the two structured data types in ABAP. The data type of an internal table is fully specified by its line type,
    key, and table type.
    Line type
    The line type of an internal table can be any data type. The data type of an internal table is normally a structure. Each component of the
    structure is a column in the internal table. However, the line type may also be elementary or another internal table.
    Key
    The key identifies table rows. There are two kinds of key for internal tables - the standard key and a user-defined key. You can specify
    whether the key should be UNIQUE or NON-UNIQUE. Internal tables with a unique key cannot contain duplicate entries. The uniqueness
    depends on the table access method.
    If a table has a structured line type, its default key consists of all of its non-numerical columns that are not references or themselves
    internal tables. If a table has an elementary line type, the default key is the entire line. The default key of an internal table whose line type
    is an internal table, the default key is empty.
    The user-defined key can contain any columns of the internal table that are not references or themselves internal tables. Internal tables
    with a user-defined key are called key tables. When you define the key, the sequence of the key fields is significant. You should remember
    this, for example, if you intend to sort the table according to the key.
    Table type
    The table type determines how ABAP will access individual table entries. Internal tables can be divided into three types:
    Standard tables have an internal linear index. From a particular size upwards, the indexes of internal tables are administered as trees. In
    this case, the index administration overhead increases in logarithmic and not linear relation to the number of lines. The system can access
    records either by using the table index or the key. The response time for key access is proportional to the number of entries in the table.
    The key of a standard table is always non-unique. You cannot specify a unique key. This means that standard tables can always be filled
    very quickly, since the system does not have to check whether there are already existing entries.
    Sorted tables are always saved sorted by the key. They also have an internal index. The system can access records either by using the
    table index or the key. The response time for key access is logarithmically proportional to the number of table entries, since the system
    uses a binary search. The key of a sorted table can be either unique or non-unique. When you define the table, you must specify whether
    the key is to be unique or not. Standard tables and sorted tables are known generically as index tables.
    Hashed tables have no linear index. You can only access a hashed table using its key. The response time is independent of the number of
    table entries, and is constant, since the system access the table entries using a hash algorithm. The key of a hashed table must be unique.
    When you define the table, you must specify the key as UNIQUE.
    Generic Internal Tables
    Unlike other local data types in programs, you do not have to specify the data type of an internal table fully. Instead, you can specify a
    generic construction, that is, the key or key and line type of an internal table data type may remain unspecified. You can use generic
    internal tables to specify the types of field symbols and the interface parameters of procedures . You cannot use them to declare data
    objects.
    Internal Tables as Dynamic Data Objects
    Data objects that are defined either with the data type of an internal table, or directly as an internal table, are always fully defined in
    respect of their line type, key and access method. However, the number of lines is not fixed. Thus internal tables are dynamic data objects,
    since they can contain any number of lines of a particular type. The only restriction on the number of lines an internal table may contain are
    the limits of your system installation. The maximum memory that can be occupied by an internal table (including its internal administration)
    is 2 gigabytes. A more realistic figure is up to 500 megabytes. An additional restriction for hashed tables is that they may not contain more
    than 2 million entries. The line types of internal tables can be any ABAP data types - elementary, structured, or internal tables. The
    individual lines of an internal table are called table lines or table entries. Each component of a structured line is called a column in the
    internal table.
    Choosing a Table Type
    The table type (and particularly the access method) that you will use depends on how the typical internal table operations will be most
    frequently executed.
    Standard tables
    This is the most appropriate type if you are going to address the individual table entries using the index. Index access is the quickest
    possible access. You should fill a standard table by appending lines (ABAP APPEND statement), and read, modify and delete entries by
    specifying the index (INDEX option with the relevant ABAP command). The access time for a standard table increases in a linear relationship
    with the number of table entries. If you need key access, standard tables are particularly useful if you can fill and process the table in
    separate steps. For example, you could fill the table by appending entries, and then sort it. If you use the binary search option with key
    access, the response time is logarithmically proportional to the number of table entries.
    Sorted tables
    This is the most appropriate type if you need a table which is sorted as you fill it. You fill sorted tables using the INSERT statement. Entries
    are inserted according to the sort sequence defined through the table key. Any illegal entries are recognized as soon as you try to add
    them to the table. The response time for key access is logarithmically proportional to the number of table entries, since the system always
    uses a binary search. Sorted tables are particularly useful for partially sequential processing in a LOOP if you specify the beginning of the
    table key in the WHERE condition.
    Hashed tables
    This is the most appropriate type for any table where the main operation is key access. You cannot access a hashed table using its index.
    The response time for key access remains constant, regardless of the number of table entries. Like database tables, hashed tables always
    have a unique key. Hashed tables are useful if you want to construct and use an internal table which resembles a database table or for
    processing large amounts of data.
    Creating Internal Tables
    Like other elements in the ABAP type concept, you can declare internal tables as abstract data
    types in programs or in the ABAP Dictionary, and then use them to define data objects.
    Alternatively, you can define them directly as data objects. When you create an internal table as a
    data object, you should ensure that only the administration entry which belongs to an internal
    table is declared statically. The minimum size of an internal table is 256 bytes. This is important if an
    internal table occurs as a component of an aggregated data object, since even empty internal
    tables within tables can lead to high memory usage. (In the next functional release, the size of the
    table header for an initial table will be reduced to 8 bytes). Unlike all other ABAP data objects, you
    do not have to specify the memory required for an internal table. Table rows are added to and
    deleted from the table dynamically at runtime by the various statements for adding and deleting
    records.
    You can create internal tables in different types.
    You can create standard internal table and then make it sort in side the program.
    The same way you can change to hashed internal tables also.
    There will be some performance issues with regard to standard internal tables/ hashed internal
    tables/ sorted internal tables.
    Internal table types
    This section describes how to define internal tables locally in a program. You can also define internal tables globally as data types in the
    ABAP Dictionary.
    Like all local data types in programs , you define internal tables using the TYPES statement. If you do not refer to an existing table type
    using the TYPE or LIKE addition, you can use the TYPES statement to construct a new local internal table in your program.
    TYPES <t> TYPE|LIKE <tabkind> OF <linetype> [WITH <key>]
    [INITIAL SIZE <n>].
    After TYPE or LIKE, there is no reference to an existing data type. Instead, the type constructor occurs:
    <tabkind> OF <linetype> [WITH <key>]
    The type constructor defines the table type <tabkind>, the line type <linetype>, and the key <key> of the internal table <t>.
    You can, if you wish, allocate an initial amount of memory to the internal table using the INITIAL SIZE addition.
    Table type
    You can specify the table type <tabkind> as follows:
    Generic table types
    INDEX TABLE
    For creating a generic table type with index access.
    ANY TABLE
    For creating a fully-generic table type.
    Data types defined using generic types can currently only be used for field symbols and for interface parameters in procedures . The generic
    type INDEX TABLE includes standard tables and sorted tables. These are the two table types for which index access is allowed. You cannot
    pass hashed tables to field symbols or interface parameters defined in this way. The generic type ANY TABLE can represent any table. You
    can pass tables of all three types to field symbols and interface parameters defined in this way. However, these field symbols and
    parameters will then only allow operations that are possible for all tables, that is, index operations are not allowed.
    Fully-Specified Table Types
    STANDARD TABLE or TABLE
    For creating standard tables.
    SORTED TABLE
    For creating sorted tables.
    HASHED TABLE
    For creating hashed tables.
    Fully-specified table types determine how the system will access the entries in the table in key operations. It uses a linear search for
    standard tables, a binary search for sorted tables, and a search using a hash algorithm for hashed tables.
    Line type
    For the line type <linetype>, you can specify:
    Any data type if you are using the TYPE addition. This can be a predefined ABAP type, a local type in the program, or a data type from the
    ABAP Dictionary. If you specify any of the generic elementary types C, N, P, or X, any attributes that you fail to specify (field length, number
    of decimal places) are automatically filled with the default values. You cannot specify any other generic types.
    Any data object recognized within the program at that point if you are using the LIKE addition. The line type adopts the fully-specified data
    type of the data object to which you refer. Except for within classes, you can still use the LIKE addition to refer to database tables and
    structures in the ABAP Dictionary (for compatibility reasons).
    All of the lines in the internal table have the fully-specified technical attributes of the specified data type.
    Key
    You can specify the key <key> of an internal table as follows:
    [UNIQUE|NON-UNIQUE] KEY <col1> ... <col n>
    In tables with a structured line type, all of the components <coli> belong to the key as long as they are not internal tables or references,
    and do not contain internal tables or references. Key fields can be nested structures. The substructures are expanded component by
    component when you access the table using the key. The system follows the sequence of the key fields.
    [UNIQUE|NON-UNIQUE] KEY TABLE LINE
    If a table has an elementary line type (C, D, F, I, N, P, T, X), you can define the entire line as the key. If you try this for a table whose line
    type is itself a table, a syntax error occurs. If a table has a structured line type, it is possible to specify the entire line as the key. However,
    you should remember that this is often not suitable.
    [UNIQUE|NON-UNIQUE] DEFAULT KEY
    This declares the fields of the default key as the key fields. If the table has a structured line type, the default key contains all non-numeric
    columns of the internal table that are not and do not contain references or internal tables. If the table has an elementary line type, the
    default key is the entire line. The default key of an internal table whose line type is an internal table, the default key is empty.
    Specifying a key is optional. If you do not specify a key, the system defines a table type with an arbitrary key. You can only use this to
    define the types of field symbols and the interface parameters of procedures . For exceptions, refer to Special Features of Standard Tables.
    The optional additions UNIQUE or NON-UNIQUE determine whether the key is to be unique or non-unique, that is, whether the table can
    accept duplicate entries. If you do not specify UNIQUE or NON-UNIQUE for the key, the table type is generic in this respect. As such, it can
    only be used for specifying types. When you specify the table type simultaneously, you must note the following restrictions:
    You cannot use the UNIQUE addition for standard tables. The system always generates the NON-UNIQUE addition automatically.
    You must always specify the UNIQUE option when you create a hashed table.
    Initial Memory Requirement
    You can specify the initial amount of main memory assigned to an internal table object when you define the data type using the following
    addition:
    INITIAL SIZE <n>
    This size does not belong to the data type of the internal table, and does not affect the type check. You can use the above addition to
    reserve memory space for <n> table lines when you declare the table object.
    When this initial area is full, the system makes twice as much extra space available up to a limit of 8KB. Further memory areas of 12KB each
    are then allocated.
    You can usually leave it to the system to work out the initial memory requirement. The first time you fill the table, little memory is used. The
    space occupied, depending on the line width, is 16 <= <n> <= 100.
    It only makes sense to specify a concrete value of <n> if you can specify a precise number of table entries when you create the table and
    need to allocate exactly that amount of memory (exception: Appending table lines to ranked lists). This can be particularly important for
    deep-structured internal tables where the inner table only has a few entries (less than 5, for example).
    To avoid excessive requests for memory, large values of <n> are treated as follows: The largest possible value of <n> is 8KB divided by the
    length of the line. If you specify a larger value of <n>, the system calculates a new value so that n times the line width is around 12KB.
    Examples
    TYPES: BEGIN OF LINE,
    COLUMN1 TYPE I,
    COLUMN2 TYPE I,
    COLUMN3 TYPE I,
    END OF LINE.
    TYPES ITAB TYPE SORTED TABLE OF LINE WITH UNIQUE KEY COLUMN1.
    The program defines a table type ITAB. It is a sorted table, with line type of the structure LINE and a unique key of the component
    COLUMN1.
    TYPES VECTOR TYPE HASHED TABLE OF I WITH UNIQUE KEY TABLE LINE.
    TYPES: BEGIN OF LINE,
    COLUMN1 TYPE I,
    COLUMN2 TYPE I,
    COLUMN3 TYPE I,
    END OF LINE.
    TYPES ITAB TYPE SORTED TABLE OF LINE WITH UNIQUE KEY COLUMN1.
    TYPES: BEGIN OF DEEPLINE,
    FIELD TYPE C,
    TABLE1 TYPE VECTOR,
    TABLE2 TYPE ITAB,
    END OF DEEPLINE.
    TYPES DEEPTABLE TYPE STANDARD TABLE OF DEEPLINE
    WITH DEFAULT KEY.
    The program defines a table type VECTOR with type hashed table, the elementary line type I and a unique key of the entire table line. The
    second table type is the same as in the previous example. The structure DEEPLINE contains the internal table as a component. The table
    type DEEPTABLE has the line type DEEPLINE. Therefore, the elements of this internal table are themselves internal tables. The key is the
    default key - in this case the column FIELD. The key is non-unique, since the table is a standard table.
    Internal table objects
    Internal tables are dynamic variable data objects. Like all variables, you declare them using the DATA statement. You can also declare static
    internal tables in procedures using the STATICS statement, and static internal tables in classes using the CLASS-DATA statement. This
    description is restricted to the DATA statement. However, it applies equally to the STATICS and CLASS-DATA statements.
    Reference to Declared Internal Table Types
    Like all other data objects, you can declare internal table objects using the LIKE or TYPE addition of the DATA statement.
    DATA <itab> TYPE <type>|LIKE <obj> [WITH HEADER LINE].
    Here, the LIKE addition refers to an existing table object in the same program. The TYPE addition can refer to an internal type in the
    program declared using the TYPES statement, or a table type in the ABAP Dictionary.
    You must ensure that you only refer to tables that are fully typed. Referring to generic table types (ANY TABLE, INDEX TABLE) or not
    specifying the key fully is not allowed (for exceptions, refer to Special Features of Standard Tables).
    The optional addition WITH HEADER line declares an extra data object with the same name and line type as the internal table. This data
    object is known as the header line of the internal table. You use it as a work area when working with the internal table (see Using the
    Header Line as a Work Area). When you use internal tables with header lines, you must remember that the header line and the body of the
    table have the same name. If you have an internal table with header line and you want to address the body of the table, you must indicate
    this by placing brackets after the table name (<itab>[]). Otherwise, ABAP interprets the name as the name of the header line and not of the
    body of the table. You can avoid this potential confusion by using internal tables without header lines. In particular, internal tables nested
    in structures or other internal tables must not have a header line, since this can lead to ambiguous expressions.
    TYPES VECTOR TYPE SORTED TABLE OF I WITH UNIQUE KEY TABLE LINE.
    DATA: ITAB TYPE VECTOR,
    JTAB LIKE ITAB WITH HEADER LINE.
    MOVE ITAB TO JTAB. <- Syntax error!
    MOVE ITAB TO JTAB[].
    The table object ITAB is created with reference to the table type VECTOR. The table object JTAB has the same data type as ITAB. JTAB also
    has a header line. In the first MOVE statement, JTAB addresses the header line. Since this has the data type I, and the table type of ITAB
    cannot be converted into an elementary type, the MOVE statement causes a syntax error. The second MOVE statement is correct, since
    both operands are table objects.
    Declaring New Internal Tables
    You can use the DATA statement to construct new internal tables as well as using the LIKE or TYPE addition to refer to existing types or
    objects. The table type that you construct does not exist in its own right; instead, it is only an attribute of the table object. You can refer to
    it using the LIKE addition, but not using TYPE. The syntax for constructing a table object in the DATA statement is similar to that for defining
    a table type in the TYPES statement.
    DATA <itab> TYPE|LIKE <tabkind> OF <linetype> WITH <key>
    [INITIAL SIZE <n>]
    [WITH HEADER LINE].
    As when you define a table type , the type constructor
    <tabkind> OF <linetype> WITH <key>
    defines the table type <tabkind>, the line type <linekind>, and the key <key> of the internal table <itab>. Since the technical attributes of
    data objects are always fully specified, the table must be fully specified in the DATA statement. You cannot create generic table types (ANY
    TABLE, INDEX TABLE), only fully-typed tables (STANDARD TABLE, SORTED TABLE, HASHED TABLE). You must also specify the key and whether
    it is to be unique (for exceptions, refer to Special Features of Standard Tables).
    As in the TYPES statement, you can, if you wish, allocate an initial amount of memory to the internal table using the INITIAL SIZE addition.
    You can create an internal table with a header line using the WITH HEADER LINE addition. The header line is created under the same
    conditions as apply when you refer to an existing table type.
    DATA ITAB TYPE HASHED TABLE OF SPFLI
    WITH UNIQUE KEY CARRID CONNID.
    The table object ITAB has the type hashed table, a line type corresponding to the flat structure SPFLI from the ABAP Dictionary, and a
    unique key with the key fields CARRID and CONNID. The internal table ITAB can be regarded as an internal template for the database table
    SPFLI. It is therefore particularly suitable for working with data from this database table as long as you only access it using the key.

  • Urgent: how to add additional records to hashed table

    Hi,
    I want to add records to a hashed table.
    my code is:
    data: ipn_pc_zoba type hashed table of tpn_pc_zoba with unique key vbeln.
    loop at izoba into wzoba.
    clear wpn_pc_zoba .
    read table ipn_pc_zoba into wpn_pc_zoba with key vbeln = wzoba-LS_KDAUF.
    if sy-subrc ne 0.
    wpn_pc_zoba-vbeln = wzoba-LS_KDAUF.
    append wpn_pc_zoba to ipn_pc_zoba.
    endif.
    endloop.
    The Error is :    You cannot use explicit or implicit index operations on tables with types "HASHED TABLE" or "ANY TABLE". "IPN_PC_ZOBA" has the type "HASHED TABLE". It is possible that .
    How to solve this?
    Please reply ASAP.
    Regards,
    SRI

    In your code you should use
    INSERT WPN_PC_ZOBA INTO IPN_PC_ZOBA.
    This is the only way to append data to a hashed table. It will also only work as long as wpn_pc_zoba-vbeln is unique in the hashed table.
    If you are getting an error, what does the error say?
    Michael

  • Problem - Inserting Records into Hashed Tables

    Help for an ABAP Newbie...
    How do I insert records into a hashed table?
    I am trying the following, but get the error message,
    *You cannot use explicit or implicit index operations with types "HASHED TABLE" or "ANY TABLE".  "LT_UNIQUE_NAME_KEYS" has the type "HASHED TABLE".
    TYPES: BEGIN OF idline,
        id TYPE i,
        END OF idline.
      DATA: lt_unique_name_keys TYPE HASHED TABLE OF idline WITH UNIQUE KEY id,
            ls_unique_name_key LIKE LINE OF lt_unique_name_keys.
    " Create a record and attempt to insert it into the internal table.
    " Why does this cause a compilation error message?
    ls_unique_name_key-id = 1.
      INSERT ls_unique_name_key INTO lt_unique_name_keys.
    Thanks,
    Walter

    INSERT ls_unique_name_key INTO TABLE lt_unique_name_keys.

  • Isuue in adding additional records to hashed table

    Hi,
    I want to add records to a hashed table.
    my code is:
    data: ipn_pc_zoba type hashed table of tpn_pc_zoba with unique key vbeln,
    wpn_pc_zoba like line of ipn_pc_zoba.
    loop at izoba into wzoba.
    clear wpn_pc_zoba .
    read table ipn_pc_zoba into wpn_pc_zoba with key vbeln = wzoba-LS_KDAUF.
    if sy-subrc ne 0.
    wpn_pc_zoba-vbeln = wzoba-LS_KDAUF.
    append wpn_pc_zoba to ipn_pc_zoba.
    endif.
    endloop.
    The Error is : You cannot use explicit or implicit index operations on tables with types "HASHED TABLE" or "ANY TABLE". "IPN_PC_ZOBA" has the type "HASHED TABLE". It is possible that .
    How to solve this?
    Please reply ASAP.
    Regards,
    SRI

    Hi,
    use
    insert wpn_pc_zoba into table ipn_pc_zoba.
    to insert the new record into the hashed table.
    Regards,
    Thomas Langen

  • List, hash table

    Is it possible to implement a List with a hash table?

    The Java "collections" all use different methods of holding the data. Each is suited to different circumstances.
    Vector and ArrayList keep the data in a plain vanilla array, but with the magic that they keep track of how much of the array is actually being used, and if you try to add another entry when the array is full, they make a new, bigger array, copy all the data from the old array to the new array, and then make the old array available for garbage collection. (The main difference between Vector and ArrayList is that Vector is synchronized, i.e. it will not become corrupted if multiple threads attempt to access it at the same time. ArrayList is not synchronized, which means that in the normal case where only one thread is accessing it, it is faster.)
    In a LinkedList each entry has handles to the next entry in the list and the previous entry.
    In a Hashtable the entries are stored in an array, but the index of the array entry is calculated using a formula based on the hash key. The hash formula is basically, divide the hashkey by the number of entries in the array and take the remainder. The hashkey itself depends on the object, but basically it is a formula that generates an integer out of something that can be considered teh "key value" of the object. It is possible -- indeed it happens all the time -- that two different objects will have the same hash key or that two objects with different hash keys will hash to the same index, so hashtable does some extra work to deal with such "collisions".
    Each has its advantages. You can find an entry very quickly in a Hashtable: you find the hashkey, perform the hash function, go to that entry in the array, and kablam, you're there. The time to find an entry in the hashtable is independent of the number of entries in the table. Compare this to a Vector or LinkedList, where the only one to find a desired entry is to start at the beginning and search one by one until you find the one you want. The main drawback to a Hashtable is that the order you get out of the hash function is essentially random. You can read a Hashtable sequentially but the order has no particular significance.
    A LinkedList is a good choice when order is important and there are a lot of inserts and/or deletes in the middle of the list. All that is necessary to add an entry is to change the handles on the entries that come before and after. While in your mind you might picture all the entries after being moved down to make room, physically none of them have to move, all that changes is handles. The main drawbacks to a LinkedList are: (a) there's some overhead involved in storing the handles and keeping them updated; and (b) it's not easy to jump to an arbitrary entry number, like if you want #12, you would have to loop through the first 11.
    Vector and ArrayList are fast and simple when you are only or mostly adding or removing from the end of the list, and when you don't often need to search by key.

  • URGENT - Sorting Hash Tables

    I am using a hash table with 2 columns. The first one has strings and is the key. The second column has integers.
    I need to sort this table on the first column and print the contents of the table.
    Then i need to sort it on the second column and print the results.
    How do i sort the hastables.
    Please let me know as soon as possible.
    Thanks and Regards,
    Vijay

    You got it all wrong. Hashtables cannot be sorted because then it would not be a hashtable. The content of the Hashtable can be sorted.
    What you want to do is get the key Set (keySet() method) of the Hashtable, wrap it in a List (e.g. LinkedList), sort that (see java.util.Collections for sorting) and then print out the contents of the Hashtable in the order pointed out by the keys in the sorted List.
    Then you can do the same for the values() Collection of the Hashtable.
    Pointers:
    http://java.sun.com/j2se/1.4/docs/api/java/util/Hashtable.html
    http://java.sun.com/j2se/1.4/docs/api/java/util/Set.html
    http://java.sun.com/j2se/1.4/docs/api/java/util/List.html
    http://java.sun.com/j2se/1.4/docs/api/java/util/LinkedList.html
    http://java.sun.com/j2se/1.4/docs/api/java/util/Collections.html

  • Question about sorted, hashed tables, mindset when using OO concepts...

    Hello experts,
    I just want to make sure if my idea about sorted and hashed table is correct.Please give tips and suggestions.
    In one of my reports, I declared a structure and an itab.
    TYPES: BEGIN OF t_mkpf,
            mblnr           LIKE mkpf-mblnr,
            mjahr           LIKE mkpf-mjahr,
            budat           LIKE mkpf-budat,
            xblnr(10)       TYPE c,
            tcode2          LIKE mkpf-tcode2,
            cputm           LIKE mkpf-cputm,
            blart           LIKE mkpf-blart,
          END OF t_mkpf.
    it_mkpf       TYPE SORTED   TABLE OF t_mkpf WITH HEADER LINE
                                       WITH NON-UNIQUE KEY mblnr mjahr.
    Now, I declared it as a sorted table with a non-unique key MBLNR and MJAHR. Now suppose I have 1000 records in my itab. how will it search for a particular record?
    2. Is it faster than sorting a standard table then reading it using binary search?
    3. How do I use a hashed table effectively? lets say that I want to use hashed type instead of sorted table in my example above.
    4. I am currently practicing ABAP Objects and my problem is that I think my mindset when programming a report is still the 'procedural one'. How do one use ABAP concepts effectively?
    Again, thank you guys and have a nice day!

    Hi Viray,
    <b>The different ways to fill an Internal Table:</b>
    <b>append&sort</b>
    This is the simplest one. I do appends on a standard table and then a sort.
    data: lt_tab type standard table of ...
    do n times.
    ls_line = ...
    append ls_line to lt_tab.
    enddo.
    sort lt_tab.
    The thing here is the fast appends and the slow sort - so this is interesting how this will compare to the following one.
    <b>read binary search & insert index sy-tabix</b>
    In this type I also use a standard table, but I read to find the correct insert index to get a sorted table also.
    data: lt_tab type standard table of ...
    do n times.
    ls_line = ...
    read table lt_tab transporting no fields with key ... binary search.
    if sy-subrc <> 0.
      insert ls_line into lt_tab index sy-tabix.
    endif.
    enddo.
    <b>sorted table with non-unique key</b>
    Here I used a sorted table with a non-unique key and did inserts...
    data: lt_tab type sorted table of ... with non-unique key ...
    do n times.
    ls_line = ...
    insert ls_line into table lt_tab.
    enddo.
    <b>sorted table with unique key</b>
    The coding is the same instead the sorted table is with a unique key.
    data: lt_tab type sorted table of ... with unique key ...
    do n times.
    ls_line = ...
    insert ls_line into table lt_tab.
    enddo.
    <b>hashed table</b>
    The last one is the hashed table (always with unique key).
    data: lt_tab type hashed table of ... with unique key ...
    do n times.
    ls_line = ...
    insert ls_line into table lt_tab.
    enddo.
    <b>You Can use this Program to Test:</b>
    types:
      begin of local_long,
        key1 type char10,
        key2 type char10,
        data1 type char10,
        data2 type char10,
        data3 type i,
        data4 type sydatum,
        data5 type numc10,
        data6 type char32,
        data7 type i,
        data8 type sydatum,
        data9 type numc10,
        dataa type char32,
        datab type i,
        datac type sydatum,
        datad type numc10,
        datae type char32,
        dataf type i,
        datag type sydatum,
        datah type numc10,
        datai type char32,
        dataj type i,
        datak type sydatum,
        datal type numc10,
        datam type char32,
        datan type i,
        datao type sydatum,
        datap type numc10,
        dataq type char32,
        datar type i,
        datas type sydatum,
        datat type numc10,
        datau type char32,
        datav type i,
        dataw type sydatum,
        datax type numc10,
        datay type char32,
        dataz type i,
        data11 type numc10,
        data21 type char32,
        data31 type i,
        data41 type sydatum,
        data51 type numc10,
        data61 type char32,
        data71 type i,
        data81 type sydatum,
        data91 type numc10,
        dataa1 type char32,
        datab1 type i,
        datac1 type sydatum,
        datad1 type numc10,
        datae1 type char32,
        dataf1 type i,
        datag1 type sydatum,
        datah1 type numc10,
        datai1 type char32,
        dataj1 type i,
        datak1 type sydatum,
        datal1 type numc10,
        datam1 type char32,
        datan1 type i,
        datao1 type sydatum,
        datap1 type numc10,
        dataq1 type char32,
        datar1 type i,
        datas1 type sydatum,
        datat1 type numc10,
        datau1 type char32,
        datav1 type i,
        dataw1 type sydatum,
        datax1 type numc10,
        datay1 type char32,
        dataz1 type i,
      end of local_long.
    data:
      ls_long type local_long,
      lt_binary type standard table of local_long,
      lt_sort_u type sorted table of local_long with unique key key1 key2,
      lt_sort_n type sorted table of local_long with non-unique key key1 key2,
      lt_hash_u type hashed table of local_long with unique key key1 key2,
      lt_apsort type standard table of local_long.
    field-symbols:
      <ls_long> type local_long.
    parameters:
      min1 type i default 1,
      max1 type i default 1000,
      min2 type i default 1,
      max2 type i default 1000,
      i1 type i default 100,
      i2 type i default 200,
      i3 type i default 300,
      i4 type i default 400,
      i5 type i default 500,
      i6 type i default 600,
      i7 type i default 700,
      i8 type i default 800,
      i9 type i default 900,
      fax type i default 1000.
    types:
      begin of measure,
        what(10) type c,
        size(6) type c,
        time type i,
        lines type i,
        reads type i,
        readb type i,
        fax_s type i,
        fax_b type i,
        fax(6) type c,
        iter type i,
      end of measure.
    data:
      lt_time type standard table of measure,
      lt_meantimes type standard table of measure,
      ls_time type measure,
      lv_method(7) type c,
      lv_i1 type char10,
      lv_i2 type char10,
      lv_f type f,
      lv_start type i,
      lv_end type i,
      lv_normal type i,
      lv_size type i,
      lv_order type i,
      lo_rnd1 type ref to cl_abap_random_int,
      lo_rnd2 type ref to cl_abap_random_int.
    get run time field lv_start.
    lo_rnd1 = cl_abap_random_int=>create( seed = lv_start min = min1 max = max1 ).
    add 1 to lv_start.
    lo_rnd2 = cl_abap_random_int=>create( seed = lv_start min = min2 max = max2 ).
    ls_time-fax = fax.
    do 5 times.
      do 9 times.
        case sy-index.
          when 1. lv_size = i1.
          when 2. lv_size = i2.
          when 3. lv_size = i3.
          when 4. lv_size = i4.
          when 5. lv_size = i5.
          when 6. lv_size = i6.
          when 7. lv_size = i7.
          when 8. lv_size = i8.
          when 9. lv_size = i9.
        endcase.
        if lv_size > 0.
          ls_time-iter = 1.
          clear lt_apsort.
          ls_time-what = 'APSORT'.
          ls_time-size = lv_size.
          get run time field lv_start.
          do lv_size times.
            perform fill.
            append ls_long to lt_apsort.
          enddo.
          sort lt_apsort by key1 key2.
          get run time field lv_end.
          ls_time-time = lv_end - lv_start.
          ls_time-reads = 0.
          ls_time-readb = 0.
          ls_time-lines = lines( lt_apsort ).
          get run time field lv_start.
          do.
            add 1 to ls_time-readb.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_apsort
              assigning <ls_long>
              with key key1 = lv_i1
                       key2 = lv_i2
              binary search.
            if sy-subrc = 0.
              <ls_long>-data11 = sy-index.
            endif.
            get run time field lv_end.
            subtract lv_start from lv_end.
            if lv_end >= ls_time-time.
              exit.
            endif.
          enddo.
          get run time field lv_start.
          do.
            add 1 to ls_time-reads.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_apsort
              assigning <ls_long>
              with key key2 = lv_i1
                       key1 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data11 = sy-index.
            endif.
            get run time field lv_end.
            subtract lv_start from lv_end.
            if lv_end >= ls_time-time.
              exit.
            endif.
          enddo.
          get run time field lv_start.
          do fax times.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_apsort
              assigning <ls_long>
              with key key1 = lv_i1
                       key2 = lv_i2
              binary search.
            if sy-subrc = 0.
              <ls_long>-data21 = sy-index.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-fax_b = lv_end - lv_start.
          get run time field lv_start.
          do fax times.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_apsort
              assigning <ls_long>
              with key key2 = lv_i1
                       key1 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data21 = sy-index.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-fax_s = lv_end - lv_start.
          collect ls_time into lt_time.
          clear lt_binary.
          ls_time-what = 'BINARY'.
          ls_time-size = lv_size.
          get run time field lv_start.
          do lv_size times.
            perform fill.
            read table lt_binary
              transporting no fields
              with key key1 = ls_long-key1
                       key2 = ls_long-key2
              binary search.
            if sy-index <> 0.
              insert ls_long into lt_binary index sy-tabix.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-time = lv_end - lv_start.
          ls_time-reads = 0.
          ls_time-readb = 0.
          ls_time-lines = lines( lt_binary ).
          get run time field lv_start.
          do.
            add 1 to ls_time-readb.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_binary
              assigning <ls_long>
              with key key1 = lv_i1
                       key2 = lv_i2
              binary search.
            if sy-subrc = 0.
              <ls_long>-data11 = sy-index.
            endif.
            get run time field lv_end.
            subtract lv_start from lv_end.
            if lv_end >= ls_time-time.
              exit.
            endif.
          enddo.
          get run time field lv_start.
          do.
            add 1 to ls_time-reads.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_binary
              assigning <ls_long>
              with key key2 = lv_i1
                       key1 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data11 = sy-index.
            endif.
            get run time field lv_end.
            subtract lv_start from lv_end.
            if lv_end >= ls_time-time.
              exit.
            endif.
          enddo.
          get run time field lv_start.
          do fax times.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_binary
              assigning <ls_long>
              with key key1 = lv_i1
                       key2 = lv_i2
              binary search.
            if sy-subrc = 0.
              <ls_long>-data21 = sy-index.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-fax_b = lv_end - lv_start.
          get run time field lv_start.
          do fax times.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_binary
              assigning <ls_long>
              with key key2 = lv_i1
                       key1 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data21 = sy-index.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-fax_s = lv_end - lv_start.
          collect ls_time into lt_time.
          clear lt_sort_n.
          ls_time-what = 'SORT_N'.
          ls_time-size = lv_size.
          get run time field lv_start.
          do lv_size times.
            perform fill.
            insert ls_long into table lt_sort_n.
          enddo.
          get run time field lv_end.
          ls_time-time = lv_end - lv_start.
          ls_time-reads = 0.
          ls_time-readb = 0.
          ls_time-lines = lines( lt_sort_n ).
          get run time field lv_start.
          do.
            add 1 to ls_time-readb.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_sort_n
              assigning <ls_long>
              with table key key1 = lv_i1
                             key2 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data11 = sy-index.
            endif.
            get run time field lv_end.
            subtract lv_start from lv_end.
            if lv_end >= ls_time-time.
              exit.
            endif.
          enddo.
          get run time field lv_start.
          do.
            add 1 to ls_time-reads.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_sort_n
              assigning <ls_long>
              with key key2 = lv_i1
                       key1 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data11 = sy-index.
            endif.
            get run time field lv_end.
            subtract lv_start from lv_end.
            if lv_end >= ls_time-time.
              exit.
            endif.
          enddo.
          get run time field lv_start.
          do fax times.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_sort_n
              assigning <ls_long>
              with table key key1 = lv_i1
                             key2 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data21 = sy-index.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-fax_b = lv_end - lv_start.
          get run time field lv_start.
          do fax times.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_sort_n
              assigning <ls_long>
              with key key2 = lv_i1
                       key1 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data21 = sy-index.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-fax_s = lv_end - lv_start.
          collect ls_time into lt_time.
          clear lt_sort_u.
          ls_time-what = 'SORT_U'.
          ls_time-size = lv_size.
          get run time field lv_start.
          do lv_size times.
            perform fill.
            insert ls_long into table lt_sort_u.
          enddo.
          get run time field lv_end.
          ls_time-time = lv_end - lv_start.
          ls_time-reads = 0.
          ls_time-readb = 0.
          ls_time-lines = lines( lt_sort_u ).
          get run time field lv_start.
          do.
            add 1 to ls_time-readb.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_sort_u
              assigning <ls_long>
              with table key key1 = lv_i1
                             key2 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data11 = sy-index.
            endif.
            get run time field lv_end.
            subtract lv_start from lv_end.
            if lv_end >= ls_time-time.
              exit.
            endif.
          enddo.
          get run time field lv_start.
          do.
            add 1 to ls_time-reads.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_sort_u
              assigning <ls_long>
              with key key2 = lv_i1
                       key1 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data11 = sy-index.
            endif.
            get run time field lv_end.
            subtract lv_start from lv_end.
            if lv_end >= ls_time-time.
              exit.
            endif.
          enddo.
          get run time field lv_start.
          do fax times.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_sort_u
              assigning <ls_long>
              with table key key1 = lv_i1
                             key2 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data21 = sy-index.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-fax_b = lv_end - lv_start.
          get run time field lv_start.
          do fax times.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_sort_u
              assigning <ls_long>
              with key key2 = lv_i1
                       key1 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data21 = sy-index.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-fax_s = lv_end - lv_start.
          collect ls_time into lt_time.
          clear lt_hash_u.
          ls_time-what = 'HASH_U'.
          ls_time-size = lv_size.
          get run time field lv_start.
          do lv_size times.
            perform fill.
            insert ls_long into table lt_hash_u.
          enddo.
          get run time field lv_end.
          ls_time-time = lv_end - lv_start.
          ls_time-reads = 0.
          ls_time-readb = 0.
          ls_time-lines = lines( lt_hash_u ).
          get run time field lv_start.
          do.
            add 1 to ls_time-readb.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_hash_u
              assigning <ls_long>
              with table key key1 = lv_i1
                             key2 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data11 = sy-index.
            endif.
            get run time field lv_end.
            subtract lv_start from lv_end.
            if lv_end >= ls_time-time.
              exit.
            endif.
          enddo.
          get run time field lv_start.
          do.
            add 1 to ls_time-reads.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_hash_u
              assigning <ls_long>
              with key key2 = lv_i1
                       key1 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data11 = sy-index.
            endif.
            get run time field lv_end.
            subtract lv_start from lv_end.
            if lv_end >= ls_time-time.
              exit.
            endif.
          enddo.
          get run time field lv_start.
          do fax times.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_hash_u
              assigning <ls_long>
              with table key key1 = lv_i1
                             key2 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data21 = sy-index.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-fax_b = lv_end - lv_start.
          get run time field lv_start.
          do fax times.
            lv_i1 = lo_rnd1->get_next( ).
            lv_i2 = lo_rnd2->get_next( ).
            read table lt_hash_u
              assigning <ls_long>
              with key key2 = lv_i1
                       key1 = lv_i2.
            if sy-subrc = 0.
              <ls_long>-data21 = sy-index.
            endif.
          enddo.
          get run time field lv_end.
          ls_time-fax_s = lv_end - lv_start.
          collect ls_time into lt_time.
        endif.
      enddo.
    enddo.
    sort lt_time by what size.
    write: / ' type      | size   | time        | tab-size    | directread  | std read    | time direct | time std read'.
    write: / sy-uline.
    loop at lt_time into ls_time.
      write: / ls_time-what, '|', ls_time-size, '|', ls_time-time, '|', ls_time-lines, '|', ls_time-readb, '|', ls_time-reads, '|', ls_time-fax_b, '|', ls_time-fax_s.
    endloop.
    form fill.
      lv_i1 = lo_rnd1->get_next( ).
      lv_i2 = lo_rnd2->get_next( ).
      ls_long-key1 = lv_i1.
      ls_long-key2 = lv_i2.
      ls_long-data1 = lv_i1.
      ls_long-data2 = lv_i2.
      ls_long-data3 = lv_i1.
      ls_long-data4 = sy-datum + lv_i1.
      ls_long-data5 = lv_i1.
      ls_long-data6 = lv_i1.
      ls_long-data7 = lv_i1.
      ls_long-data8 = sy-datum + lv_i1.
      ls_long-data9 = lv_i1.
      ls_long-dataa = lv_i1.
      ls_long-datab = lv_i1.
      ls_long-datac = sy-datum + lv_i1.
      ls_long-datad = lv_i1.
      ls_long-datae = lv_i1.
      ls_long-dataf = lv_i1.
      ls_long-datag = sy-datum + lv_i1.
      ls_long-datah = lv_i1.
      ls_long-datai = lv_i1.
      ls_long-dataj = lv_i1.
      ls_long-datak = sy-datum + lv_i1.
      ls_long-datal = lv_i1.
      ls_long-datam = lv_i1.
      ls_long-datan = sy-datum + lv_i1.
      ls_long-datao = lv_i1.
      ls_long-datap = lv_i1.
      ls_long-dataq = lv_i1.
      ls_long-datar = sy-datum + lv_i1.
      ls_long-datas = lv_i1.
      ls_long-datat = lv_i1.
      ls_long-datau = lv_i1.
      ls_long-datav = sy-datum + lv_i1.
      ls_long-dataw = lv_i1.
      ls_long-datax = lv_i1.
      ls_long-datay = lv_i1.
      ls_long-dataz = sy-datum + lv_i1.
      ls_long-data11 = lv_i1.
      ls_long-data21 = lv_i1.
      ls_long-data31 = lv_i1.
      ls_long-data41 = sy-datum + lv_i1.
      ls_long-data51 = lv_i1.
      ls_long-data61 = lv_i1.
      ls_long-data71 = lv_i1.
      ls_long-data81 = sy-datum + lv_i1.
      ls_long-data91 = lv_i1.
      ls_long-dataa1 = lv_i1.
      ls_long-datab1 = lv_i1.
      ls_long-datac1 = sy-datum + lv_i1.
      ls_long-datad1 = lv_i1.
      ls_long-datae1 = lv_i1.
      ls_long-dataf1 = lv_i1.
      ls_long-datag1 = sy-datum + lv_i1.
      ls_long-datah1 = lv_i1.
      ls_long-datai1 = lv_i1.
      ls_long-dataj1 = lv_i1.
      ls_long-datak1 = sy-datum + lv_i1.
      ls_long-datal1 = lv_i1.
      ls_long-datam1 = lv_i1.
      ls_long-datan1 = sy-datum + lv_i1.
      ls_long-datao1 = lv_i1.
      ls_long-datap1 = lv_i1.
      ls_long-dataq1 = lv_i1.
      ls_long-datar1 = sy-datum + lv_i1.
      ls_long-datas1 = lv_i1.
      ls_long-datat1 = lv_i1.
      ls_long-datau1 = lv_i1.
      ls_long-datav1 = sy-datum + lv_i1.
      ls_long-dataw1 = lv_i1.
      ls_long-datax1 = lv_i1.
      ls_long-datay1 = lv_i1.
      ls_long-dataz1 = sy-datum + lv_i1.
    endform.".
    Thanks & Regards,
    YJR.

  • What is the difference between standard,sorted and hash table

    <b>can anyone say what is the difference between standard,sorted and hash tabl</b>

    Hi,
    Standard Tables:
    Standard tables have a linear index. You can access them using either the index or the key. If you use the key, the response time is in linear relationship to the number of table entries. The key of a standard table is always non-unique, and you may not include any specification for the uniqueness in the table definition.
    This table type is particularly appropriate if you want to address individual table entries using the index. This is the quickest way to access table entries. To fill a standard table, append lines using the (APPEND) statement. You should read, modify and delete lines by referring to the index (INDEX option with the relevant ABAP command). The response time for accessing a standard table is in linear relation to the number of table entries. If you need to use key access, standard tables are appropriate if you can fill and process the table in separate steps. For example, you can fill a standard table by appending records and then sort it. If you then use key access with the binary search option (BINARY), the response time is in logarithmic relation to
    the number of table entries.
    Sorted Tables:
    Sorted tables are always saved correctly sorted by key. They also have a linear key, and, like standard tables, you can access them using either the table index or the key. When you use the key, the response time is in logarithmic relationship to the number of table entries, since the system uses a binary search. The key of a sorted table can be either unique, or non-unique, and you must specify either UNIQUE or NON-UNIQUE in the table definition. Standard tables and sorted tables both belong to the generic group index tables.
    This table type is particularly suitable if you want the table to be sorted while you are still adding entries to it. You fill the table using the (INSERT) statement, according to the sort sequence defined in the table key. Table entries that do not fit are recognised before they are inserted. The response time for access using the key is in logarithmic relation to the number of
    table entries, since the system automatically uses a binary search. Sorted tables are appropriate for partially sequential processing in a LOOP, as long as the WHERE condition contains the beginning of the table key.
    Hashed Tables:
    Hashes tables have no internal linear index. You can only access hashed tables by specifying the key. The response time is constant, regardless of the number of table entries, since the search uses a hash algorithm. The key of a hashed table must be unique, and you must specify UNIQUE in the table definition.
    This table type is particularly suitable if you want mainly to use key access for table entries. You cannot access hashed tables using the index. When you use key access, the response time remains constant, regardless of the number of table entries. As with database tables, the key of a hashed table is always unique. Hashed tables are therefore a useful way of constructing and
    using internal tables that are similar to database tables.
    Regards,
    Ferry Lianto

  • Sorted and hashed tables

    what happens when duplicate entries are present in sorted and hashed tables?

    Hi,
    Sorted internal tables can be of two types:
    unique or non unique.
    If u enter duplicate records in Sorted tables with unique  it will show error.
    If u enter duplicate records in Sorted tables with  non-unique key it will not show error.
    Hashed tables are with only unique key
    so no way to enter the duplicate records.
    for more information see the following link
    http://help.sap.com/saphelp_nw70/helpdata/en/fc/eb35de358411d1829f0000e829fbfe/content.htm
    Reward if helpful.
    Jagadish

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