topic Re: internal tables in Application Development and Automation Discussions

internal tables

Former Member — Thu, 19 Apr 2007 11:57:08 GMT

what is the purpose of using internal tables ?

Re: internal tables

Former Member — Thu, 19 Apr 2007 11:59:34 GMT

Hi,

Internal tables are used 2 store humongous amount of data. they are the substitues for arrays in abap.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.

regards,

kiran kumar k

Message was edited by:

kiran kumar

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:00:25 GMT

In a nutshell, internal tables are used to temporarily store data from the database for you to work on within your programs. They are populated by using SQL syntax - either native SQL (eg ORacle, MS) or Open SQL (SAP specific). Open SQL is the preferred option as is platform independant.

Kind regards

andy

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:03:01 GMT

Hi,

The main purpose of using internal tables is to take out the burden on database..

See let us suppose 10 persons are using MARA table and modifying it or fetching data from it or doing some manupulations..

So if they are not using internal table , all of them together are hitting the mara table and thus the performance of data from database will become very low and reports etc will run very slowly..

If they are using internal table by fetching data from the MARA and doing manupulation in there system , It is specific to that system performance and thus the peroformance of DATABASE will be finally good is using internal tables..

rewards points if useful

regards,

nazeer

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:03:34 GMT

Hi,

Please go through this link to have more idea on internal tables.

http://www.sap-img.com/ab009.htm

Rgds

Preeti

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:05:13 GMT

Hi,

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.

Regards

Sudheer

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:18:46 GMT

Hi,

Internal tables are basically structures, which are used to store data.

The data,which is needed to be displayed, say, in the form of a report output,

is fetched first in the internal table, from the database table, and is then displayed.

Using internal tables decreases the number of hits to the actual database, and in this way, increases the performance of the program.

Eg. of an internal table:-

Types:begin of itab_struct,

..... "Data declarations

end of itab_struct.

Data:itab type table of itab_struct.

data:wa_itab like line of itab_struct. "Workarea.

Thnaks and regards,

Prerna

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:21:42 GMT

Hi,

While adding or retrieving records to / from internal table we have to keep the record temporarily.

The area where this record is kept is called as work area for the internal table. The area must have the same structure as that of internal table. An internal table consists of a body and an optional header line.

Header line is a implicit work area for the internal table. It depends on how the internal table is declared that the itab will have the header line or not.

Declaration of internal table:

e.g.

data: begin of itab occurs 10,

ab type c,

cd type i,

end of itab. " this table will have the header line.

Regards,

Subashini.J

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:23:15 GMT

Hi Naga Mrudula,

Internal tables

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.

Hope this resolves your query.

Reward all the helpful answers.

Regards

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:24:02 GMT

hi mrudula,

Long life data are stored in the database table. We can't afford to lose data from the database table. Hence v need of a intermediate table where v can put in all our datas and work with that, thus avoiding accidental loss of data.

This intermediate tables are nothing but called as internal tables, which are created during runtime and reserves no memory.

There are 3 types of internal tables.

1)standard

2)sorted

3)hashed.

Regards...

Arun.

Reward points if useful.

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:30:39 GMT

why we will loose data.

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:35:27 GMT

SAP R/3 is working on application server, it does not have its own database.

It fetches data from database through native SQL (as per database like oracle, DB2, sybase etc)

This data it stores in INTERNAL TABLES just like a buffer withn the application server. The data manipulation is done on application server by playing with INTERNAL TABLES.

Finally the end output ITAB is stored back to DB.

Thanks

Sandeep

Reward if helpful

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:44:17 GMT

Hi Naga mrudula,

Internal tables are a very important concept of ABAP.

They are use to store the data of database tables temporarily.

This is done to ensure that the Database is not accessed continuously.

You can do any processing on the data in the internal tables and finally save the processed data from the internal table to the database table.

ABAP doesn't support arrays.

Internal table is like multi dimensional arrays where you can store data in

rows and columns.

It contains header line.

Header line is nothing but a work area of the table.

Either you can have header line in the internal table or you can declare a work area separately.

HEADER & BODY: Every table(be it internal or transparent)contains two sections: Header and Body.

Header is a workarea of the table which acts as an interface for the table. Header can have only one record at a time

Body is the entire table containing the data or records. Body is a collection of records.

Structure of header and body are same for a particular table.

Example,

internal table.

data: begin of itab occurs 0,

matnr like mara-matnr,

maktx like makt-maktx,

end of itab.

Thanks and Regards,

Archana Suresh

Re: internal tables

Former Member — Thu, 19 Apr 2007 12:49:30 GMT

Internal tables

1)Internal tables means of taking data from a fixed structure and storing it in working memory in ABAP.

2) 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.

3) An internal table is a run time instance. It get created when program starts execution.

4)It get destroyed when program terminates. it has two different parts. HeaderLine(optional) & Body(Compulsory).

5)Any value that comes to or goes from interanal table , that travels through headerline.

A related program is .

*declaration.

data: begin of inernaltable occurs 0,

x type c,

y type i,

end of itab.

*initializing headerline

internaltable-x = 'd'.

internaltable-y = 34.

*storing value into internal table

appene internaltable .

*reading internal table

loop at itab .

write: / internaltable-x, internaltable-y. "writes to output list

endloop.

hope this helps u,

reward points if useful

Thanks,

Ginni