topic Re: tables in Application Development and Automation Discussions

tables

Former Member — Sun, 30 Dec 2007 09:31:45 GMT

how can u differentiate or identify the data of cluster n pooled tables?

Re: tables

Former Member — Mon, 31 Dec 2007 04:01:49 GMT

Hi,

goto the tcode se16 and give the table name DD06L.

In that we have the clustered and pooled tables.

pooled tables doesnt maintain a primary key.

where as clustered tables maintain primary key.

reward points, it helpful,

regards,

satish.

Re: tables

Former Member — Mon, 31 Dec 2007 04:08:16 GMT

Pooled table is an integration of two or more tables .it enhances efficiency by reducing time of search by binary search.

Cluster table is similar to pooled but all the tables clustered will have similar primary key.

A table in the database in which all records from the pooled tables assigned to the table pool are stored corresponds to a table pool.

The definition of a pool consists essentially of two key fields (Tabname and Varkey) and a long argument field (Vardata).

Table Clusters Several logical data records from different cluster tables can be stored together in one physical record in a table cluster.

A cluster key consists of a series of freely definable key fields and a field (Pageno) for distinguishing continuation records. A cluster also contains a long field (Vardata) that contains the contents of the data fields of the cluster tables for this key. If the data does not fit into the long field, continuation records are created. Control information on the structure of the data string is still written at the beginning of the Vardata field.

Examples

Pool tables are: A005,A001

Cluster table:BSEG

Regards,

Maha

Re: tables

Former Member — Mon, 31 Dec 2007 06:05:30 GMT

Hai friend,

I read a lot of documentation about Pooled & Cluster tables. I saw this accidentally but the information you gave is very useful than any docs that I have read before.

Thanks,

Eswar.

Re: tables

Former Member — Mon, 31 Dec 2007 11:28:27 GMT

Hi this might help u.

The following are the table types used in SAP :

Transparent Tables

There is a physical table on the database for each transparent table.

The names of the physical table and the logical table definition in the

ABAP/4 Dictionary agree. All the business and application data is store

in transparent tables.

Pooled table

Pooled tables can be used to store control data (e.g. screen sequences,

program parameters or temporary data). Several pooled tables can be

combined to form a table pool. The table pool corresponds to a physical

table on the database in which all the records of the allocated pooled

tables are stored.

Cluster table

Cluster tables contain continuous text, for example documentation.

Several cluster tables can be combined to form a table cluster. Several

logical lines of different tables are combined to form a physical record

in this table category. This permits object-by-object storage or

object-by-object access. In order to combine tables in clusters, at

least part of the keys must agree. Several cluster tables are stored in

one corresponding table on the database.

I. Transparent tables (BKPF, VBAK, VBAP, KNA1, COEP)

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

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

II. Pool Tables (match codes, look up tables)

Should be accessed via primary key or

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

No secondary indexes

Select * is Ok because all columns retrieved anyway

III. Cluster Tables (BSEG,BSEC)

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

No secondary indexes

Select * is Ok because all columns retrieved anyway. Performing an operation on multiple rows is more efficient than single row operations. Therefore you still want to select into an internal table. If many rows are being selected into the internal table, you might still like to retrieve specific columns to cut down on the memory required.

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

Can not be buffered

IV. Buffered Tables (includes both Transparent & Pool Tables)

While buffering database tables in program memory (SELECT into internal table) is generally a good idea for performance, it is not always necessary. Some tables are already buffered in memory. These are mostly configuration tables. If a table is already buffered, then a select statement against it is very fast. To determine if a table is buffered, choose the 'technical settings' soft button from the data dictionary display of a table (SE12). Pool tables should all be buffered.

Tables Documentation

https://www.sdn.sap.com/irj/sdn/go/portal/prtroot/docs/library/uuid/25c1f5d1-0901-0010-d495-e96d02a0cb01

with regards,

Hema Sundara.

pls give points if found helpful.