3 different table type

 

 

 

Transparent tables

nPool tables

nCluster tables

nBuffered Tables (includes both Transparent & Pool Tables)

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Transparent tables

EG:BKPF, VBAK, VBAP, KNA1, COEP

nExist in dictionary

nCan be buffered (SE11->Display Table->technical settings) Heavily updated tables should not be buffered.

nAllows secondary indexes (SE11->Display Table->Indexes) 

   

The primary index is always created automatically in the R/3 System. It consists of the primary key fields of the database table.

secondary index: a key which is created other than primary key, to speed up processing

 

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 nPool tables

nLogical table and store control data

nCan be combine many pool tables and update

    

  in one database table

nShould be accessed via primary key

nShould be buffered (SE11->Display Table->technical settings)

nNo secondary indexes

nSelect * is Ok because all columns retrieved anyway

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nCluster tables

 

EG:BSEG ,BSEC

nShould be accessed via primary key - very fast retrieval otherwise very slow

nNo secondary indexes

nSelect * is Ok because all columns retrieved anyway. Performing an operation on multiple rows is more efficient than single row operations.

nStatistical SQL functions (SUM, AVG, MIN, MAX, etc) not supported

nCan not be buffered

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nBuffered Tables  

nincludes both Transparent & Pool Tables

nbuffering database tables in program memory

nTo determine if a table is buffered, choose the 'technical settings' soft button from the data dictionary display of a table (SE12)

nPool tables should all be buffered