Creation of Sorted and Standard and Hashed Internal Tables ..

Question

Hi ..
Pls  specify me.. how to create .. sorted ,Standard and Hashed Internal Tables...
pls give me  the full code  regarding ...this ..
Thnks

Answer 1

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.
Special Features of Standard Tables
Unlike sorted tables, hashed tables, and key access to internal tables, which were only introduced in Release 4.0, standard tables already existed several releases previously. Defining a line type, table type, and tables without a header line have only been possible since Release 3.0. For this reason, there are certain features of standard tables that still exist for compatibility reasons.
Standard Tables Before Release 3.0
Before Release 3.0, internal tables all had header lines and a flat-structured line type. There were no independent table types. You could only create a table object using the OCCURS addition in the DATA statement, followed by a declaration of a flat structure:
DATA: BEGIN OF <itab> OCCURS <n>,
<fi> ...
END OF <itab>.
This statement declared an internal table <itab> with the line type defined following the OCCURS addition. Furthermore, all internal tables had header lines.
The number <n> in the OCCURS addition had the same meaning as in the INITIAL SIZE addition from Release 4.0. Entering ‘0’ had the same effect as omitting the INITIAL SIZE addition. In this case, the initial size of the table is determined by the system.
The above statement is still possible in Release 4.0, and has roughly the same function as the following statements:
TYPES: BEGIN OF <itab>,
<fi> ...,
END OF <itab>.
DATA <itab> TYPE STANDARD TABLE OF <itab>
WITH NON-UNIQUE DEFAULT KEY
INITIAL SIZE <n>
WITH HEADER LINE.
In the original statement, no independent data type <itab> is created. Instead, the line type only exists as an attribute of the data object <itab>.
Standard Tables From Release 3.0
Since Release 3.0, it has been possible to create table types using
TYPES <t> TYPE|LIKE <linetype> OCCURS <n>.
and table objects using
DATA <itab> TYPE|LIKE <linetype> OCCURS <n> WITH HEADER LINE.
The effect of the OCCURS addition is to construct a standard table with the data type <linetype>. The line type can be any data type. The number <n> in the OCCURS addition has the same meaning as before Release 3.0. Before Release 4.0, the key of an internal table was always the default key, that is, all non-numeric fields that were not themselves internal tables.
The above statements are still possible in Release 4.0, and have the same function as the following statements:
TYPES|DATA <itab> TYPE|LIKE STANDARD TABLE OF <linetype>
WITH NON-UNIQUE DEFAULT KEY
INITIAL SIZE <n>
WITH HEADER LINE.
They can also be replaced by the following statements:
Standard Tables From Release 4.0
When you create a standard table, you can use the following forms of the TYPES and DATA statements. The addition INITIAL SIZE is also possible in all of the statements. The addition WITH HEADER LINE is possible in the DATA statement.
Standard Table Types
Generic Standard Table Type:
TYPES <itab> TYPE|LIKE STANDARD TABLE OF <linetype>.
The table key is not defined.
Fully-Specified Standard Table Type:
TYPES <itab> TYPE|LIKE STANDARD TABLE OF <linetype>
WITH NON-UNIQUE <key>.
The key of a fully-specified standard table is always non-unique.
Standard Table Objects
Short Forms of the DATA Statement :
DATA <itab> TYPE|LIKE STANDARD TABLE OF <linetype>.
DATA <itab> TYPE|LIKE STANDARD TABLE OF <linetype>
WITH DEFAULT KEY.
Both of these DATA statements are automatically completed by the system as follows:
DATA <itab> TYPE|LIKE STANDARD TABLE OF <linetype>
WITH NON-UNIQUE DEFAULT KEY.
The purpose of the shortened forms of the DATA statement is to keep the declaration of standard tables, which are compatible with internal tables from previous releases, as simple as possible. When you declare a standard table with reference to the above type, the system automatically adopts the default key as the table key.
Fully-Specified Standard Tables:
DATA <itab> TYPE|LIKE STANDARD TABLE OF <linetype>
WITH NON-UNIQUE <key>.
The key of a standard table is always non-unique.
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.
plz reward if useful