Internal Table : occurs statement

What is the meaning of using "occurs" statement in Internal Table. What does it imply?
DATA: BEGIN OF ITAB OCCURS 10,
END OF ITAB.
What difference it will make if suppose I use "OCCURS 0" or "OCCURS 10" ?

Hi yogesh for more clearification
difference b/w occurs 0 & occurs n
The number <N> indicate how many lines has to have the table in initialization time: i.e. when the program is loaded in memory, the space for the table depends on the initialization numbers of the records.
AT run time if the table needs more space, this'll automatically be enhanced.
But If you know your table can have a certain numbers of records, you can indicate it in the defination, what'll improve the performance:
all the space the table needs is taken at the beginin, so it doesn't need to enhance the space at run time.
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."
and it is better to use occus 0 inplace of occurs n because of above specified reasons
while it is not recommended to use occurs for internal table declaration and it has become obselete
reward if helpful

Similar Messages

Internal table occurs 0 --------- why obsolate?

Hi,
Can anybody tell why the declaration of internal table occurs 0 and internal table with header line is obsolate now?
Explain the adavantages of newer one.
is there any performance related issue?
Thanks in advance
Debjani Lahiri

Hi,
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.
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.
Regards,
Bhaskar

"IT_SPFLI" is not an internal table "OCCURS n" specification is missing.

I follow this tutorial. I replaced the 2 tables into sflight and spfli table.
http://www.****************/Tutorials/BSP/UsingTableView/demo.htm
and this error occurred.
"IT_SPFLI" is not an internal table "OCCURS n" specification is missing.

You'll need to create a table type for spfli and sflight. If you check the tutorial, the two tables it_vbak and it_vbap are typed on zvbak and zvbap respectively, not vbak and vbap. Here, zvbak and zvbap have presumably already been defined in the DD as table types for vbak and vbap.
Regards,
Trond

Internal table -Select statement -2nd plant is not being filled

Hi,
Second field for plant WERKD is not getting filled in this table.I am using into corresponding fields of table ITAB statement.
I need both plants and in single select statement.
Any ideas?
DATA: BEGIN OF T_STOF OCCURS 0,
 VBELN LIKE LIPS-VBELN,
 ERNAM LIKE LIPS-ERNAM,
 WERKS LIKE LIPS-WERKS,
 NTGEW LIKE LIPS-NTGEW,
 GEWEI LIKE LIPS-GEWEI,
 EBELN LIKE EKKO-EBELN,
 WERKD LIKE EKPO-WERKS,
 LGORT LIKE EKPO-LGORT,
 EBELP LIKE EKPO-EBELP,
 MATNR LIKE EKPO-MATNR,
 TXZ01 LIKE EKPO-TXZ01,
 AEDAT LIKE EKPO-AEDAT,
 KNUMV LIKE EKKO-KNUMV,
 END OF T_STOF.
SELECT LIKPVBELN LIKPERNAM LIPSWERKS LIPSNTGEW LIPS~GEWEI
EKKOEBELN EKPOWERKS EKPOLGORT EKPOEBELP EKPOMATNR EKPOTXZ01 EKPOAEDAT EKKOKNUMV
INTO CORRESPONDING FIELDS OF TABLE T_STOF
FROM LIKP
INNER JOIN LIPS
ON LIKPVBELN EQ LIPSVBELN
INNER JOIN EKKO
ON LIPSVGBEL EQ EKKOEBELN
INNER JOIN EKPO
ON EKKOEBELN EQ EKPOEBELN
WHERE LIKP~VBELN IN S_VBELN
AND LIKP~ERNAM IN S_ERNAM
AND LIPS~WERKS IN S_WERKS
AND EKKO~EBELN IN S_EBELN
AND EKPO~WERKS IN S_WERKD
AND EKPO~LGORT IN S_LGORT
AND EKPO~MATNR IN S_MATNR
AND EKPO~AEDAT IN S_AEDAT
AND BSART = 'UB'.
Or am i doing in wrong?
Regards
Praveen

Hi,
If you use INTO CORRESPONDING then the fieldname in the internal table has to match the selecting field name..
To avoid this you can use INTO TABLE...
SELECT LIKPVBELN LIKPERNAM LIPSWERKS LIPSNTGEW LIPS~GEWEI
EKKOEBELN EKPOWERKS EKPOLGORT EKPOEBELP EKPOMATNR EKPOTXZ01 EKPOAEDAT EKKOKNUMV
INTO TABLE T_STOF
Thanks,
Naren

Internal table Read statement

Hi,
AM using Read statement to read internal table as below.
Read itab into wa with key x = y.
if sy-subrc eq 0.
do some thing.
endif.
However the work area wa is not useful to me in my program. when am doing extended check it is issueing warning saying wa is not used. HOW TO CLOSE THIS WARNING.
Regards,
AAkash

just before read statement do
CLEAR WA.
This should remove the error.
Cheers
VJ

Internal table occurs

hi
wht is the diff b/w occurs 'n' in the declaration of Internal table.....
i know that occurs 0 will give 8kb of size, then wht is occurs 1, 2 .....
is it goes with multiples of 8 i mean 1 implies 16kb or 64 kb
plz clear,
thanks in advance
ganesh

hi,
Occurs means it holds the records of the internal table n by default its size is 8kb.if we take it as occurs 1 then it occupies the space required for one record by doubling the size. if field string size is 30 n boby size is 8 kb n if we have given occurs 1 then the body size becomes 30.if we give occurs 2 then it doubles ...then the fieldstring n body size will be 60 kb.......hope u understood this.
if it has solved ur problem then dont forget to reward with points.
with regards,
madhuri.

Internal Table occurs n Error - BSP

I have declared a type as
Types: BEGIN OF ty_mara
MATNR TYPE MARA-MATNR,
ENDOF ty_mara.
Problem is it is giving me error that "NO INTERNAL TABLE IS CREATED, OCCURS N SPECIFICATION".
Need Directions.
Edited by: NiksRules on Feb 14, 2011 6:25 AM

Hi,
I assume that you declared the types in "Type definitions" and trying the use this in page attributes for an internal table.
Is this correct?
If so, you need to have another type declaration like
types: ty_mara_table type table of ty_mara.
use the type ty_mara_table in the page attributes.
Regards,
Ravi.

Reg : internal table & Perform statement

hi all
     i have 3 internal tables ,
*     in first internal table i have mark-1 ,*
*     in 2nd internal table i have mark-2 ,*
*     using "PERFORM" i have to add mark 1 & mark 2*
*     and i need to display the total in 3rd internal table.*
*     how to do by using "PERFORM" .*
                Kindly clarify.
with kind regards
vel

Raghupathy is right you just have to write:
porgram code......
perform sum_of_tables tables itab1
                                           itab2
                                           itab3.
program code....
definition of form:
form_sum_of_tables tables itab1
                                      itab2
                                      itab3.
definiton type of witab1, witab2, witab3.
loop itab1 into witab1.
loop itab2 into witab2.
witab3-total = witab1-mark1 plus witab2-mark2.
append witab3 to itab3.
endloop.
endloop.
endform.
It will return itab3 which is sum of itab1 and itab2.

Question in ABAP syntax, read & insert data from internal table, while loop

Hi, SDN Fellow.
I am from Java background and learnt ABAP, I don't usually write much ABAP code.
I am trying to implement the following logic in a RFC now.
I have one z-custom database table, the structure as the following:
It has two columns, with these sample data.
Says datable table is ZEMPMGRTAB.
EmployeeID,ManagerID
user10,user1
user9,user1
user8,user1
user7,user2
user6,user2
user5,user2
user4,user2
user2,user1
The logic is this:
I have a input parameter, userid. I am using this parameter to have a select statement to query the record into export table,EXPTAB 'LIKE' table ZEMPMGRTAB.
SELECT * FROM ZEMPMGRTAB
into table EXPTAB
   WHERE EMPLOYEEID = USERID.
Say, my parameter value, USERID ='USER4'.
Referring to the sample data above, I can get the record of this in my EXPTAB,
EmployeeID,ManagerID
user4,user2
Now, I want to iterately use the EXPTABLE-ManagerID
as the USERID input in SELECT statement, until it has no return result. Then, insert the new records in
EXPTAB.
In above new loop case, we will get this table content in EXPTAB,
EmployeeID,ManagerID
user4,user2
user2,user1
I kind of think of the pseudocode logic as below:
(These may not be a valid ABAP code, so I need help to convert/correct them)
DATA:
IWA TYEP ZZEMPMGRTAB,
ITAB
HASHED TABLE OF ZZEMPMGRTAB
WITH UNIQUE KEY EMPLOYEEID.
SELECT * FROM ZEMPMGRTAB
into table ITAB
   WHERE EMPLOYEEID = USERID.
*Question 1: I cannot insert a internal table to export table, it is *incompatible type, what is the alternative way fo this?
*Question 2: How can I access thedata of the internal table like this,ITAB-MANAGERID? As if I can, I would do this:
* IWA-EMPLOYEEE = ITAB-EMPLOYEEID. IWA-MANAGERID = IWA-MANAGERID. INSERT IWA INTO TABLE EXPTAB.
* Question 3: Is the 'NE NULL' - 'not equal to NULL' is right syntax?
IF ITAB NE NULL.
INSERT ITAB INTO EXPTAB.
ENDIF
* Question 4: Is my WHILE loop setup right here? And are the syntax right?
WHILE ITAB NE NULL.
SELECT * FROM ZEMPMGRTAB
into table ITAB
   WHERE EMPLOYEEID = ITAB-MANAGERID.
IF ITAB NE NULL.
INSERT ITAB INTO EXPTAB.
ENDIF
REFRESH ITAB.
ENDWHILE.
Assume all the syntax and logic are right, I should get this result:
EmployeeID,ManagerID
user4,user2
user2,user1
If I have a new entry in datable table,ZEMPMGRTAB like this:
user1,user0
My pseudocode logic will get this result:
EmployeeID,ManagerID
user4,user2
user2,user1
user1,user0
I truly appreciate if you can help me to validate the above syntax and pseudocode logic.
Thanks in advance.
KC

Hi,
FUNCTION ZGETSOMEINFO3.
*"*"Local Interface:
*" IMPORTING
*"     VALUE(USERID) TYPE AWTXT
*"     VALUE(FMTYPEID) TYPE AWTXT
*" EXPORTING
*"     VALUE(RETURN) TYPE BAPIRETURN
*" TABLES
*"      APPROVERT STRUCTURE ZTAB_FMAPPROVER
*"      ACTOWNERT STRUCTURE ZTAB_FMACTOWNER
DATA: T_RESULT TYPE STANDARD TABLE OF ZTAB_FMAPPROVER.
**Question 1: For this line, I got an error says "Program ''USERID" *not found. Is the syntax right, as the USERID is a parameter for the function.
perform add_line(USERID).
ENDFUNCTION.
form add_line using i_user type ZTAB_FMAPPROVER.EMPLOYEEID
                    changing T_RESULT TYPE ZTAB_FMAPPROVER.
data: ls_row type ZTAB_FMAPPROVER.
* Get record for i_user
select single * into ls_row from ZTAB_FMAPPROVER
where EmployeeID = i_user.
if sy-subrc NE 0.
* Do nothing, there is not manager for this employee
else.
* Store result
QUESTION 2: I am still got stuck on this line of code. It still *says that "T_RESULT" is not an internal table "OCCURS n" *specification is missing. I thought the line: "T_RESULT TYPE *ZTAB_FMAPPROVER" means declare internal table, T_RESULT as type of ZTAB_FMAPPROVER". Am I understand it wrongly?
append ls_row to t_result.
* Call recursion
perform add_line using ls_row-ManagerID
                          changing t_result.
endif.
endform.
Thanks,
KC

Internal Table and Structures

Hi,
I am a beginer. I know how to create a structure and how to create an internal table using ABAP/4. My problem is, i don't understand where to use internal table and structure, also i find myself very confused about the explicit work areas.
Plese someone show me a program by explaining all of this clearly.

Hi
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.

How to read the method and put that code in 1 internal table

Hi,
Actually in the normal ABAP, if we want to read the report, then we will write read report statement.
If we want to read method then this statement will not work.
So, to read the method and put that code in 1 internal table , which statement we need to write?
Regards,
Radhika

Hi Naimesh,
Thanks for your reply.
As, i am not aware of ABAP Objects i am having some issues:
Actually that is working for some methods in some classes.
Here 1 issue is there:
In se24 1 method is there in 1 class.
Even by using that FM in SE37 i am able to get the program name by giving class and method name,
but while using that FM in the program i am not able to get that program name.
so, i am unable to read the source code of the program?
1 example here:
Class name is CL_GUI_FRONTEND_SERVICES.
in this class, methods like FILE_EXIST , FILE_GET_SIZE, etc are there.
By giving the class name and method name i am able to get the program name also,
but while using that FM in the program i am not able to get that program name.
so, i am unable to read the source code of the program?
Here is my code:
REPORT Z16059_SCAN_METHOD.
DATA: BEGIN OF I_PROGRAM OCCURS 0,
 LINE(256) TYPE C,
 END OF I_PROGRAM.
DATA METHOD TYPE PROGRAM.
DATA: BEGIN OF I_STRUCTURE,
 CLS_NAME(30) TYPE C,
 METH_NAME(61) TYPE C,
 END OF I_STRUCTURE.
I_STRUCTURE-CLS_NAME = 'CL_GUI_FRONTEND_SERVICES'.
I_STRUCTURE-METH_NAME = 'CL_GUI_FRONTEND_SERVICES-FILE_EXIST'.
CALL FUNCTION 'SEO_METHOD_GET_INCLUDE_BY_NAME'
EXPORTING
MTDKEY = I_STRUCTURE
IMPORTING
 PROGNAME = METHOD
EXCEPTIONS
 INTERNALMETHOD_NOT_EXISTING = 1
 OTHERS = 2
IF SY-SUBRC <> 0.
MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
 WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.
READ REPORT METHOD INTO I_PROGRAM.
Please help me out in this regard.
Thanks & Regards,
Radhika

Briefly about internal tables

briefly about internal tables
standerd internal tables
hash internal tables
sorted internal tables
index internal tables

Hi,
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.
Types of internal tables :
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 NON-UNIQUE. 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.
Creating Internal Tables
You define internal tables first as an abstract data type in the program or ABAP Dictionary, and then as a data object based on that, or they are declared directly as a fully specified data object. 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 size of table headers for initial tables is currently 8 bytes. This should be heeded whenever internal tables occur as components of complex data objects. Also, empty tables can use up a relatively high amount of storage space as components of tables. The size of the entire storage space required for an internal table is not defined in the declaration as is the case for data objects of the type string or xstring. Table rows are added to and deleted from the table dynamically at runtime by the various statements for adding and deleting records.
Structure of internal tables :
STRUCTURE OF INTERNAL TABLE
TYPES : BEGIN OF ITAB,
                PERNR TYPE PERSNO,
                WERKS TYPE WERKS,
               END OF ITAB.
INTERNAL TABLE DECLARATION FOR THE ABOVE STRUCTURE
DATA : INT_TAB TYPE STANDARD TABLE OF ITAB,
            WA_TAB TYPE ITAB.        "WORK AREA OF THE INTERNAL TABLE
Thanks,
Sakthi C
Rewards if useful *

Internal table when creating a class

Hi everybody
im defining parameters when defining a class
one of the parameters is IT_MARA, of type MARA
Ive declared a method - SELECT_DATA, where the code is
SELECT * FROM MARA
INTO TABLE IT_MARA....
When activating it
Im getting the error - IT_MARA is not an internal table 'OCCURS n ' specification is missing
anybody knows how to solve that issue?

Hi Anjali,
I figure out you are having trouble passing an internal table out of a method of a class.
The error you get is because the parameter you have declared using TYPE MARA actually creates a line type and not an internal table in the signature of the method.
You have to declare the parameter with a 'table type' rather, and it will create an internal table.
You could use either a global table type or a local one.
Please have a look at the code below using a local table type for this problem:
CLASS a DEFINITION.
PUBLIC SECTION.
    TYPES ty_mara TYPE TABLE OF mara.     "Local Table Type
    METHODS meth EXPORTING et_mara TYPE ty_mara.   "This makes an internal table
ENDCLASS.
CLASS a IMPLEMENTATION.
METHOD meth.
    SELECT * FROM mara INTO TABLE et_mara UP TO 10 ROWS.
ENDMETHOD.
ENDCLASS.
START-OF-SELECTION.
DATA lt_mara TYPE TABLE OF mara.
DATA lr_a    TYPE REF TO a.
CREATE OBJECT lr_a.
CALL METHOD lr_a->meth
    IMPORTING
      et_mara = lt_mara.
BREAK-POINT.

Error in passing internal table as returning parameter

Hi
Im new to ABAP OO.
I declared a parameter ret_kna1 Returning Type KNA1.
Inside the method, I am retrieving data from table KNA1 into internal table and then I want return the interal table value.
But Im not able to assing the internal table for eg : code
method READ_CUSTOMER_LIST.
data: lt_kna1 type TABLE OF kna1,
      wa_kna1 LIKE LINE OF lt_kna1.
data: lv_kunnr type kna1-kunnr,
      lv_land1 type kna1-LAND1.
SELECT * FROM kna1
INTO TABLE lt_kna1
WHERE land1 eq lv_land1.
insert LINES OF lt_kna1 INTO TABLE ret_kna1.
endmethod.
when I try to activate the error says 'ret_kna1 is not an internal table "OCCURS n" specification is missing.
but I can not declare the internal table 'ret_kna1' once again in the code, as it already defined in the parameter as type KNA1.
please help me how to assign internal table values to the returing structur.

Are you passing it as an EXPORT parameter?
use and define it in the TABLES section of your function module as so:
*" IMPORTING
*"     VALUE(INCLUDE_X_LEVELS) TYPE CHAR1 OPTIONAL
*" TABLES
*"      I_SELECTED_OU STRUCTURE HRROOTOB
*"      I_SELECTED_EE STRUCTURE OBJEC
*"      E_VIP_EPM_DISTR STRUCTURE ZHR_VIP_EPM_DISTR
*"      E_RETURN STRUCTURE BAPIRET1
That way you can pass value in the table (if needed) and then pass the table with your values based on your own logic

Doubts with control break statements on internal table loops (AT/ENDAT)

Hi, i've had a couple of doubts for a long while which I hope someone can clarify today:
1) I know how to use the AT statements, however, i'm not sure I get correctly what this part of help regarding this commands means:
"The control level structure with internal tables is static. It corresponds exactly to the sequence of columns in the internal table (from left to right). In this context, the criteria according to which you sort the internal table are unimportant."
I've always sorted the internal table before the control break and it works that way. For example:
SORT ITAB BY EBELN EBELP.
LOOP AT ITAB.
AT NEW EBELN.
* Code for the order header
ENDAT.
ENDLOOP.
If I don't sort the internal table, it doesn't work! (i get dupplicated processing). In the example, if i have more than one register with the same EBELN and they're not consecutive, the header gets processed twice. I really don't get that part of the help text.
2) I know this: "At the start of a new control level (i.e. immediately after AT), the following occurs in the output area of the current LOOP statement:
All character type fields (on the right) are filled with "*" after the current control level key.
All other fields (on the right) are set to their initial values after the current control level key."
My doubt is: WHY is that this way? Because sometimes (most times) I need those fields INSIDE the statement! So when that happened i've solved it in one of three ways:
LOOP AT ITAB INTO WA_ITAB.
WA_ITAB_AUX = WA_ITAB.
AT NEW FIELD.
 WA_ITAB = WA_ITAB_AUX.
* ...Rest of the code for the first register
ENDAT.
ENDLOOP.
LOOP AT ITAB INTO WA_ITAB.
AT NEW FIELD.
 READ TABLE ITAB INDEX SY-TABIX INTO WA_ITAB.
* ...Rest of the code for the first register
ENDAT.
ENDLOOP.
* (Without AT)
LOOP AT ITAB INTO WA_ITAB.
IF WA_ITAB-FIELD <> FIELD_AUX.
 FIELD_AUX = WA_ITAB_FIELD.
* ...Rest of the code for the first register
ENDIF.
ENDLOOP.
Is there any problem with this way of coding? Can be done better?
Thank you very much in advance.

Hi..,
1)
See if u sort the table on a field on which u r using AT ENDAT .. then all the records which are having the same value for that field will form a group or those reocrds will be at one place.. so when u sort the table for all the records AT ENDAT will get executed onli once..
If u dont sort this table on this field then all these records will be at different places and in between there may be records with different value for this field.. so this AT ENDAT will get executed for each record !!
2)
No u cannot use the Right hand fields of the field in the table .. Because these AT events work as Group based operations... So till that field on which AT ENDAT is working it breaks that record into two groups.. One is the left hand fields including that field.. and right hand fields as another group.. and makes the right hand group as stars ****. Thats y u can observe that even any one field in the left hand group changes the AT ENDAT will get executed !!!!
Hope u understood !!!
regards,
sai ramesh

Internal Table : occurs statement

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