diff refresh Vs clear of internal table

[Former Member]

Hello ABAP Experts,

What is the difference between refresh and clear of internal table.

Suggestions appreciated.

Thanks,

BWer

[suresh_datti]

REFRESH ITAB will delete the contents in the itab whereas CLEAR ITAB will only delete the header. You can simply use CLEAR:ITAB[],ITAB. to clear both the header & table contents in one go.

Regards,

Suresh Datti

[Former Member]

Hi

CLEAR <itab>.

statement. This statement restores an internal table to the state it was in immediately after you declared it. This means that the table contains no lines. However, the memory already occupied by the memory up until you cleared it remains allocated to the table.

If you are using internal tables with header lines, remember that the header line and the body of the table have the same name. If you want to address the body of the table in a comparison, you must place two brackets ([ ]) after the table name.

CLEAR <itab>[].

To ensure that the table itself has been initialized, you can use the

REFRESH <itab>.

statement. This always applies to the body of the table. As with the CLEAR statement, the memory used by the table before you initialized it remains allocated. To release the memory space, use the statement

Regards

Laxmi

[Former Member]

Hi ,

REFRESH and CLEAR are the various methods for initializing Internal Tables.

examples:

CLEAR <itab>.

If <itab> is not having header line, this will clear the entire contents.

CLEAR <itab>.

If <itab> is having header line, this statement will just clear the contents of header line.

CLEAR <itab>[]

If <itab> has header line, this will clear the body contents ( excluding header line)

REFRESH <itab>.

This statement will cause the body content to be cleared. But memory allotted to the table will remain as it is.. Then u have to use

FREE<itab> to free the memory.

Just check this link...

http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb384e358411d1829f0000e829fbfe/content.htm

Regards,

SP.

[former_member181962]

clear itab[]. = refresh itab.

Regards,

Ravi

[Former Member]

HI,

Replace always clears the body of itab,clear clears the header line when that internal table is declared with header line,if not means that internal table is not defined with header line then it clears body.If you want to clear body then you need to code it like CLEAR ITAB[].

Cheers,

Bujji

[Former Member]

hi bwer,

refresh itab: The internal table itab is reset to its initial state, i.e. all table entries are deleted.

clear itab: only clears the contents of the internal table.The header entry of a table with a header line remains unchanged. It can be reset to its initial value

hope this helps,

priya.

[Former Member]

Hii

clear itab - clears only header line

refresh itab- clears body of the internal table

Free itab - clears a internal table from memory

it deletes the internal table from the memory itself

CLEAR ITAB[] does the same thing as REFRESH ITAB.

You can use FREE to initialize an internal table and release its memory space without first using the REFRESH or CLEAR statement.

Like REFRESH, FREE works on the table body, not on the table work area.

After a FREE statement, you can address the internal table again. It still occupies the amount of memory required for its header (currently 256 bytes). When you refill the table, the system has to allocate new memory space to the lines.

it is better practice to use the FREE ITAB command whenever possible as it will maximise system resources.

If you free the memory allocated to this internal table, the memory could be allocated to another program or another data object in the same program.

chk this link

http://help.sap.com/saphelp_nw04/helpdata/en/fc/eb384e358411d1829f0000e829fbfe/content.htm

also refer to this link for more information..

<b>

Regards

Naresh

[athavanraja]

itab with header line.

clear: clears the header line.

refresh: clears the whole table.

itab without header line.

clear & Refresh : clears the whole table.

Regards

Raja

[Former Member]

hi,

clear itab. clears the header of internal table

refresh itab clears the body of itab

clear itab[] clears both the body and header.

Award points if helpful.

regards,

keerthi.

[Former Member]

hi

When CLEAR itab references an internal table itab with a header line, it only resets the subfields in the header entry to their initial values (as mentioned above). The individual table entries remain unchanged.

To delete the entire internal table together with all its entries, you can use <b>CLEAR itab[]</b> or <b>REFRESH itab.</b>

REFRESH - Delete an internal table

Variants:

1. REFRESH itab.

2. REFRESH itab FROM TABLE dbtab.

3. REFRESH itab FROM SELECT-OPTIONS.

Variant 1

REFRESH itab.

Effect

The internal table itab is reset to its initial state, i.e. all table entries are deleted.

Der Return Code SY-SUBRC is undefined.

Notes

The header entry of a table with a header line remains unchanged. It can be reset to its initial value using CLEAR.

FREE itab can be used to free up the memory allocated to the table.

Note

Performance:

The runtime required to reset an internal table depends on the amount of memory previously occupied by that table.

Resetting a small internal table takes around 15 msn (standard microseconds). Resetting a 200 KB table takes around 400 msn, and a 1 MB table, around 3000 msn.

If the internal table has an index or a hash table (because it was edited using INSERT, DELETE, SORT or COLLECT), the runtime increases slightly, since the index or hash table has to be released as well as the table itself.

Variant 2

REFRESH itab FROM TABLE dbtab.

In some cases, the syntax rules that apply to Unicode programs are different than those for non-Unicode programs. See Key Specifications and Unicode.

This variant is not allowed in an ABAP Objects context. See REFRESH FROM not Allowed.

Note

This variant is no longer maintained and should no longer be used (see also obsolete key words). Please use the SELECT ... INTO TABLE statement instead.

Effect

The internal table itab is deleted and it is then filled with the contents of the database table dbtab.

A generic argument can be used to specify a restriction to a particular part of the database table when filling (LOOP AT dbtab, READ TABLE dbtab).

The table dbtab must be declared in the program using TABLES.

Der Return Code SY-SUBRC is undefined.

Example

Delete an internal table MESSAGES, then fill the table with all messages from the table T100 with language key 'D' and ID 'RF'.

TABLES T100.

DATA MESSAGES TYPE TABLE OF T100 WITH HEADER LINE

MESSAGES-TEXT = 'Delete me'.

APPEND MESSAGES.

T100-SPRSL = 'E'.

T100-ARBGB = 'RF'.

REFRESH MESSAGES FROM TABLE T100.

Variant 3

REFRESH itab FROM SELECT-OPTIONS.

Note

This variant is no longer supported (see also obsolete key words). The equivalent functionality is now available in the function module RS_REFRESH_FROM_SELECTOPTIONS.

Effect

Deletes the internal table itab and then transfers the database selections and the selection parameters together with the values entered by the user.

Exceptions

Non-Catchable Exceptions

Cause: No more memory available to create the table

Runtime Error: REFRESH_NO_SHORT_MEMORY

plz reward if useful