Data Dictionary

[Former Member]

What is a cluster table? Give examples of cluster tables in SAP?

Message was edited by:

krishna veni

[Former Member]

hi

cluster table is a logical table. It does not exist like a transparent table in the underlying database. its a collection of logical tables.

table cluster is a physical table that holds all the cluster tables.

hence,

There are many cluster tables in one table cluster.

Thanks.

Refer:

http://help.sap.com/saphelp_nw04/helpdata/en/81/415d363640933fe10000009b38f839/frameset.htm

[Former Member]

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.

"Major difference between Standard tables, Pooled tables and Cluster Tables?”

1.A transparent table is a table that stores data directly. You can read these tables directly on the database from outside SAP with, for instance an SQL statement.

2.Transparent table is a one to one relation table i.e. when you create one transparent table then exactly same table will create in data base and if is basically used to store transaction data.

3.A clustered and a pooled table cannot be read from outside SAP because certain data are clustered and pooled in one field.

4.One of the possible reasons is for instance that their content can be variable in length and build up. Database manipulations in ABAP are limited as well.

5.But pool and cluster table is a many to one relationship table. This means many pool table store in a database table which is know as table pool.

6.All the pool table stored table in table pool does not need to have any foreign key relationship but in the case of cluster table it is must. And pool and cluster table is basically use to store application data.

7.Table pool can contain 10 to 1000 small pool tables, which can have 10 to 100 records. But cluster table can contain very big but few (1 to 10) cluster table.

8.For pool and cluster table you can create secondary index and you can use select distinct, group for pool and cluster table. You can use native SQL statement for pool and cluster table.

9.A structure is a table without data. It is only filled by program logic at the moment it is needed starting from tables.

10.A View is a way of looking at the contents of tables. It only contains the combination of the tables at the basis and the way the data needs to be represented. You actually call directly upon the underlying tables.

'The table which store information about Structures and Tables are as follows:’

DD02L - table properties

DD02T - table texts

DD03L - field properties

DD03T - field texts

Creating cluster/pool tables:

http://help.sap.com/saphelp_nw04/helpdata/en/cf/21f0b7446011d189700000e8322d00/content.htm

Creating transparent tables

http://help.sap.com/saphelp_nw04/helpdata/en/cf/21eb6e446011d189700000e8322d00/frameset.htm

regards,

srinivas

[Former Member]

Hi,

Cluster tables combine the data from several tables with identical (or almost identical) keys into one physical record on the database.

Cluster tables are --> BSEG, BSEC

[Former Member]

Cluster table - 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 type. This permits object-by-object storage or object-by-object access. In order to combine tables in clusters, at least parts of the keys must agree. Several cluster tables are stored in one corresponding table on the database.

These are logical tables that must be assigned to a table cluster when they are defined. Cluster tables can be used to strore control data. They can also be used to store temporary data or texts, such as documentation.

egs:

AUAA,AUAB,AUAO,AUAS,AUAT,AUAV,AUAW,AUAY,BSEC,BSED,BSEG,BSES,BSET,CDPOS

[Former Member]

Hi Krishna.

cluster table is a logical table. It does not exist like a transparent table in the underlying database. its a collection of logical tables.

If u want to knwon what r the cluster , pool and transperent table avaiable in sap .just follow this procedure u can find any kind table there ,

Goto se11

click the mouse in database table ,

press ctlr+f

then click on ALL Selection in application tool bar

after what ever the thing u want see just select that check box , press enter.

Regards,

Nihar Swain ...............

[Former Member]

Hi Krishna.

cluster table is a logical table. It does not exist like a transparent table in the underlying database. its a collection of logical tables.

If u want to knwon what r the cluster , pool and transperent table avaiable in sap .just follow this procedure u can find any kind table there ,

Goto se11

click the mouse in database table ,

press ctlr+f

then click on ALL Selection in application tool bar

after what ever the thing u want see just select that check box , press enter.

Regards,

Nihar Swain ...............

[Former Member]

"What is a cluster table?

Cluster table have many to 1 relationship. Cluster table are much more complex and you cannot display the data of a cluster table directly. Cluster table have be read and display via your ABAP program.

It is a logical tables that must be assigned to a table cluster when they are defined. Cluster tables can be used to strore control data. They can also be used to store temporary data or texts, such as documentation.

'Cluster Tables (BSEG,BSEC)

.

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

2.No secondary indexes .

3.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.

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

5.Can not be buffered .

Reward points if it is usefull .....

Girish