topic Re: abap in Application Development and Automation Discussions

abap

Former Member — Wed, 21 Mar 2007 09:47:36 GMT

can anybody plz explain me

what is this FOR ALL ENTRIES ?

why we should go for it ?

Re: abap

Former Member — Wed, 21 Mar 2007 09:50:11 GMT

chk this

Re: abap

Former Member — Wed, 21 Mar 2007 09:50:55 GMT

If you have some data in an internal table.

You need to get some additional data from a data base table for each record of the internal table. then you use for all entries.

select * from <table>

into table itab_final

for all entries in itab

where field = itab-field.

Regards,

Ravi

Re: abap

Former Member — Wed, 21 Mar 2007 09:51:01 GMT

Hi,

First fetch the data from a db table into an Internal table ITAB,

Using the data of this ITAB, if you wants to fetch the data from different tables then we use this command;

If not ITAB[] is initial.

select F1 F2 F3 from DB Table into ITAB1

for all entries in ITAB

where f1 = ITAB-f1.

rewrad if useful

regards,

Anji

Re: abap

Former Member — Wed, 21 Mar 2007 09:51:55 GMT

hai

in short very useful

To avoid nested select statements we use SELECT FOR ALL ENTRIES statement. If there r more than 10000 records SELECT FOR ALL ENTRIES is used. Performance wise SELECT FOR ALL ENTRIES is better to use.

**Please reward suitable points***

With Regards

Navin Khedikar

Re: abap

Former Member — Wed, 21 Mar 2007 09:52:26 GMT

Hi,

Outer join can be created using this addition to the where clause in a select statement. It speeds up the performance tremendously, but the cons of using this variation are listed below

1)Duplicates are automatically removed from the resulting data set. Hence care should be taken that the unique key of the detail line items should be given in the select statement.

2)If the table on which the For All Entries IN clause is based is empty, all rows are selected into the destination table. Hence it is advisable to check before-hand that the first table is not empty.

3)If the table on which the For All Entries IN clause is based is very large, the performance will go down instead of improving. Hence attempt should be made to keep the table size to a moderate level.

Not Recommended

Loop at int_cntry.

Select single * from zfligh into int_fligh

where cntry = int_cntry-cntry.

Append int_fligh.

Endloop.

Recommended

Select * from zfligh appending table int_fligh

For all entries in int_cntry

Where cntry = int_cntry-cntry.

regards,

bharat.

Re: abap

Former Member — Wed, 21 Mar 2007 09:52:59 GMT

Hi,

U can join 2 tables by using joins but the performance goes down. This can be overcomed by for all entries.

Advantages:-

1.The itab loop is avoided i.e. it helps in performance.

2. If you do not put all the key fields in the Select clause, duplicate entries if any will not be retrieved.

LOOP AT itab.

...

SELECT ... FROM ... WHERE ... = itab-anything.

ENDLOOP.

Here's an example:

SELECT matnr mtart

FROM mara

INTO TABLE t_mara

WHERE matnr IN s_matnr.

IF NOT t_mara[] IS INITIAL.

SELECT matnr maktx

FROM makt

INTO TABLE t_makt

FOR ALL ENTRIES IN t_mara

WHERE matnr EQ t_mara-matnr.

ENDIF.

Regards,

Priyanka.

Re: abap

Former Member — Wed, 21 Mar 2007 09:53:32 GMT

Hi,

Check this info.

we are using select for all entries to avoid inner joins..

suppose

select vbeln from vbak into corresponding fields of table itab.

if not itab[] is initial.

select <fields> from vbap into corresponding fields of table itab1 for all entries in itab where vbeln = itab-vbeln.

endif.

it will fetch the data by comparing vbeln of itab and vbap but one thing you have to check itab is initial or not if it is not initial(not contain any data) then you should not use for all entries it will fetch all the values from vbap.

For all entries

The for all entries creates a where clause, where all the entries in the driver table are combined with OR. If the number of entries in the driver table is larger than rsdb/max_blocking_factor, several similar SQL statements are executed to limit the length of the WHERE clause.

The plus

Large amount of data

Mixing processing and reading of data

Fast internal reprocessing of data

Fast

The Minus

Difficult to program/understand

Memory could be critical (use FREE or PACKAGE size)

Some steps that might make FOR ALL ENTRIES more efficient:

Removing duplicates from the the driver table

Sorting the driver table

If possible, convert the data in the driver table to ranges so a BETWEEN statement is used instead of and OR statement:

FOR ALL ENTRIES IN i_tab

WHERE mykey >= i_tab-low and

mykey <= i_tab-high.

Select using JOINS

The plus

Very large amount of data

Similar to Nested selects - when the accesses are planned by the programmer

In some cases the fastest

Not so memory critical

The minus

Very difficult to program/understand

Mixing processing and reading of data not possible

For further reference regarding optimization you can look into this link....

http://www.sapbrain.com/ARTICLES/TECHNICAL/optimization/optimization.html#Optimizing%20the%20load%20of%20the%20database

Hope this resolves your query.

Reward all the helpful answers.

Regards

Re: abap

Former Member — Wed, 21 Mar 2007 10:37:03 GMT

Hi,

For better performance we should use FOR ALL ENTRIES instead of Using SELECT statement inside Loop End Loop.

If you have to select data from more than two tables in that case frist try to join two tables get all the necessary data in one internal table then if the content of that internal table is not null, considering that internal table as a driver table you can select all the necessary data from other tables using FOR ALL ENTRIES which will give better performance.

If sounds good pl reward.

Cheers.