Diff Btn Join and For all Entries.

Former Member — Tue, 29 May 2007 07:10:32 GMT

Hi Experts I have few Questions.

1. Wht is the diff btn Join and For all entries.

2.How to find out which index being used.(other than ST05 . Even in ST05 How to look for it)

3.How to test the BAPI. (BAPI doesnt contain a COMMIT WORK stmt)

4.Wht is Diff btn VIew and Join

Straight to the point answers will be rewarded.

regards,

Kiran

Re: Diff Btn Join and For all Entries.

Former Member — Tue, 29 May 2007 07:11:49 GMT

1.Performawnce wise For all entries is better than Join.

4.View and join both are same, a join defined globally in aBAP dictionary ia caled a View.

Re: Diff Btn Join and For all Entries.

Former Member — Tue, 29 May 2007 07:14:25 GMT

Hi,

1)INNER JOIN - This is used to join two different DATABASE tables.

FOR ALL ENTRIES - This is used to avoid the SELECT inside a loop. Usually if we want the child details for all the header records of a internal table then you loop at the header table and fire the SELECT. We can avoid the SELECT inside the looop using the FOR ALL ENTRIES clause.

http://www.thespot4sap.com/articles/SAPABAPPerformanceTuning_ForAllEntries.asp

http://www.thespot4sap.com/articles/SAPABAPPerformanceTuning_InnerJoinStatement.asp

http://www.sswug.org/see/28439

http://web.mit.edu/ist/org/admincomputing/dev/abap_review_check_list.htm

http://www.sapgenie.com/abap/performance.htm

4)There are 4 types views are avilable in SAP.

Database View - To club more than one table

Projection View - To hide fields in one table

Maintanance View - To maintain database records in table

Help View - To provide help for a fields (Same functionality as Search help. This is outdated)

View are improves perfromance in the following aspects

1. If you want to use more than two table in 'JOIN' condition better to use Views . It will improves performance of a program

2. If you want to use mutiple FOR ALL ENTRIES clause, better to club all SELECT statement in a view.

note:

1.Views does not contain data in it. It fetches data from the database only depending on the condition ...

2.Views are part of data dictionary. They are a window to view the data in database

3.views can be used to give security to data. users can be allowed to view only basic data only

With group requests from different tables, use JOINs or VIEWs. The JOIN is coded directly in ABAP. You can easily adapt it to the requirements of a specific application. The VIEW, however, is specified in the DDIC, which enforces definition uniformity throughout the program. VIEWs, like any table definition, may be used in multiple areas of the program, thus reducing the number of different statements in the statement cache.

Don't use JOINs or VIEWs over tables that are buffered with their technical settings. It is possible, in principle, to buffer a VIEW, but only in rare cases when you can buffer all concerned tables as well. Buffering a VIEW means not only less performance improvement, but also a significant rise in memory allocation and overhead during buffer synchronization. If you mix buffered and unbuffered tables in one access rather than reading both table types, you always lose performance because the database interface will not use the existing buffers.

In the SAP environment, there is a small but significant difference between JOIN and VIEW: In client dependent tables, every table in the JOIN MANDT = SY-MANDT is generated as part of the WHERE clause.

For VIEW, however, this WHERE clause is generated only for the table that provides MANDT in the VIEW projection list. Even though MANDT from each of the tables can join together the VIEW tables, significant processing differences in these tables can occur within VIEW if MANDT also appears in the indexes of the other tables that are included. These differences result from the fact that database optimizers only interpret the WHERE clause of VIEW to determine the first access. Therefore, you should take MANDT from the field list of the VIEW from the table providing the most selective first access. If the secondary tables include MANDT in their indexes and a selective primary table cannot be determined, then you should not use a VIEW.

3)it is similar to the execution of any fun module.

Enter the BAPI Name in se37 tcode and press F8.

then pass the following parameters to it (depending upon the requirement you have).

DOCUMENTTYPE

DOCUMENTNUMBER

DOCUMENTPART

DOCUMENTVERSION

result will be displayed in OBJECT links.

Regards,

Priyanka.

Re: Diff Btn Join and For all Entries.

Former Member — Tue, 29 May 2007 07:15:08 GMT

1. Join is the SQL statement in which the tables on which queried are internally joined, FOR ALL ENTRIES..You first get the details in one internal table basedon that you query another DB table.

2. Go to the table through SE11 and check for indexes. Indexes are used based on the fields in where clause of the query.

3. You can't test BAPI just in SE37 as they may require lots of input so best way is write a small program to test them

4. View and Join internally behaves same. Join done in program, View make join in data dictionary defination

Regards,

Atish

Re: Diff Btn Join and For all Entries.

Former Member — Tue, 29 May 2007 07:17:25 GMT

Join : Fetching values from joining two or more DB within one select query

For all entries : using two or more select queries & in laterone fetching values for all the corresponding values fetched in first imternal table.

As SAP works on an application server, its always better to use FOR ALL ENTRIES avoding performace issue of joining two DB tables.

Thanks

Sandeep

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