topic cluster table in Application Development and Automation Discussions

cluster table

Former Member — Mon, 28 May 2007 10:59:17 GMT

hi experts,

can v create cluster n pooled tables. if yes kindly gve example.

wht is the diff b/w transparent, cluster and pooled tables

regards

alson

Re: cluster table

Former Member — Mon, 28 May 2007 11:01:51 GMT

Hi,

There are three types of tables.

1. Transparent Table

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

2. 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.

3. 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.

The major difference between transparent tables, pooled tables and clusterd Tables are:

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.

****do rewards if usefull

Regards,

vijay

Re: cluster table

Former Member — Mon, 28 May 2007 11:01:56 GMT

hi,

just create a normal table and select EXTRAS->CHANGE TABLE CATOGERY THERE U CAN CHANGE.

clustered tables:

A cluster table is similar to a pooled table. It has a many-to-one relationship with a table in the database. Many cluster tables are stored in a single table in the database called a table cluster.

pooled tables:

A pooled table in R/3 has a many-to-one relationship with a table in the database (see Figures 3.1 and 3.2). For one table in the database, there are many tables in the R/3 Data Dictionary. The table in the database has a different name than the tables in the DDIC, it has a different number of fields, and the fields have different names as well. Pooled tables are an SAP proprietary construct.

transparent tables:

A transparent table in the dictionary has a one-to-one relationship with a table in the database. Its structure in R/3 Data Dictionary corresponds to a single database table. For each transparent table definition in the dictionary, there is one associated table in the database. The database table has the same name, the same number of fields, and the fields have the same names as the R/3 table definition. When looking at the definition of an R/3 transparent table, it might seem like you are looking at the database table itself.

RGDS,

BHARAT.

Message was edited by:

Bharat Kalagara

Re: cluster table

sreeramkumar_madisetty — Mon, 28 May 2007 11:03:28 GMT

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.

Tables assigned to a table pool or table cluster are referred to as pooled tables or cluster tables.

Pooled tables

Transparent table:

A transparent table is created automatically on the database when it is activated in the ABAP Dictionary. At this time, the database-independent description of the table in the ABAP Dictionary is translated into the language of the database system used.The database table has the same name as the table in the ABAP Dictionary. The fields also have the same names in both the database and the ABAP Dictionary. The data types in the ABAP Dictionary are converted to the corresponding data types of the database system.

The order of the fields in the ABAP Dictionary can differ from that of the fields on the database. This permits you to insert new fields without having to convert the table. When you add a new field, adjust the order of the fields by changing the database catalog (ALTER TABLE). The new field is added to the database table.

Regards,

Sree

Re: cluster table

Former Member — Mon, 28 May 2007 11:08:47 GMT

Hi,

Difference Between Transparent, Cluster and Pooled Tables

1) Transparent tables (BKPF, VBAK, VBAP, KNA1, COEP)

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

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

2) Pool Tables (match codes, look up tables)

i) Should be accessed via primary key or

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

ii) No secondary indexes

iii) Select * is Ok because all columns retrieved anyway

3) Cluster Tables (BSEG,BSEC)

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

ii) No secondary indexes

iii) 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.

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

Can not be buffered

Examples of Cluster & Pooled Tables:

check this table DD02L here u can see the cluster & pooled table

to see pooled table specify pool in tabclass for cluster use cluster in tabclass.

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

AUAA

AUAB

AUAO

AUAS

AUAT

AUAV

AUAW

AUAY

BSEC

BSED

BSEG

BSES

BSET

CDPOS

Regards,

Padmam.