Solved: DIfference between table cluster and cluster table

Former Member · ‎2007 Jul 31

Dear Friends;

I wanna know the difference between cluster table and table cluster. What it actually mean to us???

Please help me out.

Regards;

Parag

Former Member · ‎2007 Jul 31

Hi,

Occasionally, several tables may be linked by a common key. The ABAP/4 Data Dictionary can also combine these tables into a single table. Each data set of the real table within the database contains a key and in a single data field, several data sets of the subsequent table for this key.

As mentioned above, these table types require special data handling, therefore they are not transparent tables.

Note: Both Pooled and Cluster Tables are stored as tables within the database. Only the structures of the two table types which represent a single logical view of the data are defined within the ABAP/4 Data Dictionary. The data is actually stored in bulk storage in a different structure. These tables are commonly loaded into memory (i.e., 'buffered') due to the fact they are typically used for storing internal control information and other types of data with little or no external (business) relevance.

Please check this link

http://www.sap-img.com/abap/the-different-types-of-sap-tables.htm

A Cluster table is a table where in More than one DDIC table is mapped to one table in the DATABASE.

And the data will be stored in archived format.

The KEY FOR Clustered table will be intersection of PRIMARY KEY's of all the DDIC tables.

You can JOIN a cluster table.

WHere as for a normal transperant table there is ONE - TO - ONE relation ship between DDIC table and DATABASE table

Regards,

Sankar

Former Member · ‎2007 Jul 31

Hi,

Occasionally, several tables may be linked by a common key. The ABAP/4 Data Dictionary can also combine these tables into a single table. Each data set of the real table within the database contains a key and in a single data field, several data sets of the subsequent table for this key.

As mentioned above, these table types require special data handling, therefore they are not transparent tables.

Note: Both Pooled and Cluster Tables are stored as tables within the database. Only the structures of the two table types which represent a single logical view of the data are defined within the ABAP/4 Data Dictionary. The data is actually stored in bulk storage in a different structure. These tables are commonly loaded into memory (i.e., 'buffered') due to the fact they are typically used for storing internal control information and other types of data with little or no external (business) relevance.

Please check this link

http://www.sap-img.com/abap/the-different-types-of-sap-tables.htm

A Cluster table is a table where in More than one DDIC table is mapped to one table in the DATABASE.

And the data will be stored in archived format.

The KEY FOR Clustered table will be intersection of PRIMARY KEY's of all the DDIC tables.

You can JOIN a cluster table.

WHere as for a normal transperant table there is ONE - TO - ONE relation ship between DDIC table and DATABASE table

Regards,

Sankar

Former Member · ‎2007 Jul 31

Hi,

are u asking diff b/w cluster table and table?

then

Hi,

A Cluster table is a table where in More than one DDIC table is mapped to one table in the DATABASE.

And the data will be stored in archived format.

The KEY FOR Clustered table will be intersection of PRIMARY KEY's of all the DDIC tables.

You can JOIN a cluster table.

WHere as for a normal transperant table there is ONE - TO - ONE relation ship between DDIC table and DATABASE table.

Regards

Former Member · ‎2007 Jul 31

What types of tables can be created in the ABAP Dictionary?

Transparent Tables

Pooled and Clustered Tables

Which field differentiates a table from client-dependent and client-independent?

The MANDT field of the table specifies whether the table is client independent or not.

What is the difference between Pooled tables and Cluster tables?

Cluster tables and Pooled tables have many to one relationship with the underlying database.

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

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

A pooled table cannot have the name having more than 10 characters.

All the key fields of the pooled table must be of character data type.

In pooled tables, the maximum length of the key field/data fields should not exceed the length of varkey/vardata of the pool respectively.

In cluster table the records having the same key are stored in a single key in the cluster.

If there is an overflow of the data records a continuation record is created with the same table key.

Also do refer

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

regards,

srinivas

*reward for useful answers*

Former Member · ‎2007 Jul 31

Go through the link below which gives the difference between table custer and custer table.

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

Hope this helps.

Former Member · ‎2007 Jul 31

Table Cluster :

Database table in the database that contains the data of several cluster tables.

Cluster Table :

Database table defined in the ABAP Dictionary, whose version on the database is not only assigned to one table defined in the ABAP Dictionary. Several cluster tables are assigned to a table cluster in the database. The intersection of the key fields of the cluster tables forms the primary key of the table cluster. The other columns of the cluster tables are stored in compressed form in a single column VARDATA of the table cluster. You can access cluster tables only via Open SQL, and only without using joins.

regards

Debjani

Reward point for helpful answer

Former Member · ‎2007 Jul 31

" What is transparent, cluster and pool table?  Where and when we use " these tables?

" 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.

" what is the major difference between Standard tables, Pooled tables and 
" Clusterd Tables?

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.

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.

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.

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.

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.

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

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.

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

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.

reward points if it is usefull

Girish

Former Member · ‎2007 Jul 31

Hi,

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.

More at this link.

http://help.sap.com/saphelp_erp2004/helpdata/en/81/415d363640933fe10000009b38f839/frameset.htm

regrds,

Reshma

Former Member · ‎2007 Jul 31

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.

refer this link also:

http://www.sap-img.com/abap/the-different-types-of-sap-tables.htm

Former Member · ‎2007 Aug 01

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: