difference between transparent table pooled table and cluster table

[Former Member]

hi experts ,

i wanted to know what is differenece between transparent table pooled table and cluster table. can any one explain me with examples.

kartik Brahme.

[Former Member]

HI,

THESE ARE SOME DIFFERENCE POINTS.

1. Transparent tables have one to one relation ship ie., the structure which defined in the data dictionary level(here we define the tables etc..) is same as in database level(here the data is stored physically).

2. we usually create transparent tables only.

3. In cluster and pooled tables they have many to one relationship ie., they have many structures or definitions at dictionary level but a single table in database level.

4. Major difference is cluster tables must have at least one primary key common but in pooled they may have or may not have a primary key in common.

5. We don’t create any cluster and pooled tables because they are in propriety format of SAP.

FOR MORE DETAILS READ THIS LINK...

<a href="http://help.sap.com/saphelp_nw04/helpdata/en/cf/21f0d1446011d189700000e8322d00/frameset.htm">http://help.sap.com/saphelp_nw04/helpdata/en/cf/21f0d1446011d189700000e8322d00/frameset.htm</a>

[Former Member]

Hi

The following are the table types used in SAP :

<b>I. Transparent tables</b> (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.

<b>II. Pool Tables</b> (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

<b>III. Cluster Tables</b> (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.

Transparent table - many to many

pooled - many to one

cluster table - many to one

poolled and cluster table both are logical tables

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.

A001,A004,A005,A006,A007,A009,A010,A012,A015,A016,A017,A018,A019,A021,A022,

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.

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

Refer link: http://help.sap.com/saphelp_nw04/helpdata/en/cf/21f083446011d189700000e8322d00/content.htm

<b>Reward if usefull</b>

[Former Member]

Transparent Table : Exists with the same structure both in dictionary as well as in database exactly with the same data and fields.

Pooled Table : Pooled tables are logical tables that must be assigned to a table pool when they are defined. Pooled tables are used to store control data. Several pooled tables can be cominied in a table pool. The data of these pooled tables are then sorted in a common table in the database.

Cluster Table : Cluster tables 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.

difference:

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.

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.

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

please reward if useful.

[Former Member]

Transparent table, Pool table and cluster table are data dictionary table objects sorted table, indexed table and hash table are internal tables.

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 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.