pooltable and cluster tables with example

[Former Member]

Hello friends,

One interviewer asked me about the pool table and cluster table. what is pool table and cluster table.

what is exact usage of pool and cluster table. As well, i want to know the table examples.

[jayanthi_jayaraman]

Hi,

Transparent Tables

The tables physically present in the DB Server as in the Application Server.

Table Pools

The data is stored as a table pool in the database server which consists of

all the (physical) records from the tables present in that particular table pool.

Technically, The table name and the field name are the key fields in case

of pooled tables.

Table Clusters

Logical data records from different tables are stored as single PHYSICAL record

in the table clusters.

Technically. There can be n number keys (usually generated by the system ) for a

record in a cluster table and field called pageno is used to track the continuation

of the records.

BOTH TABLE POOLS AND TABLE CLUSTERS ARE NOT PHYSICALLY AVAILABLE IN THE DB SERVER

BUT THEY ARE LOGICALLY POOLED OR CLUSTERED.

[Former Member]

Hi

For internal purposes, such as storing control data or update texts, there are in addition the following table categories:

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 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.

RFBLG (BSEC, BSED, BSEG, BSES, BSET )

More examples you can see in table DD02L.

Svetlin

[Former Member]

Hi,

Table pools (pools) and table clusters (clusters) are special table types in the ABAP Dictionary. The data from several different tables can be stored together in a table pool or table cluster. Tables assigned to a table pool or table cluster are referred to as pooled tables or cluster tables.

A table pool or table cluster should be used exclusively for storing internal control information (screen sequences, program parameters, temporary data, continuous texts such as documentation). All data of commercial relevance is stored exclusively in transparent tables!

Table Pools

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.

Thanks&Regards,

Ruthra.R