topic Re: table type in Application Development and Automation Discussions

table type

Former Member — Mon, 03 Mar 2008 16:03:09 GMT

plz define transparent table , pool table and cluster table with example

Re: table type

Former Member — Tue, 04 Mar 2008 05:41:24 GMT

Hi Agarwal,

1.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.

•Transparent tables are much more common than pooled or cluster tables.

•They are used to hold application data.

• Application data is the master data or transaction data used by an application.

2.Table Pools and Pooled Table

• Pooled table in R/3 has a many-to-one relationship with a table in the database.

• For one table in the database, there are many tables in the R/3 Data Dictionary.

• When you look at a pooled table in R/3, you see a description of a table.

• However, in the database, it is stored along with other pooled tables in a single table called a table pool.

• A table pool is a database table with a special structure that enables the data of many R/3 tables to be stored within it.

• It can only hold pooled tables.

• R/3 uses table pools to hold a large number (tens to thousands) of very small tables (about 10 to 100 rows each).

• Table pools reduce the amount of database resources needed when many small tables have to be open at the same time.

• SAP uses them for system data.

• Pooled tables are primarily used by SAP to hold customizing data.

3.Table Cluster and Cluster Table

• 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.

• A table cluster is similar to a table pool.

• It holds many tables within it.

• The tables it holds are all cluster tables.

• Like pooled tables, cluster tables are another proprietary SAP construct.

• They are used to hold data from a few (approximately 2 to 10) very large tables.

• They would be used when these tables have a part of their primary keys in common, and if the data in these tables are all accessed simultaneously.

Restrictions on Pooled and Cluster Tables

• Pooled and cluster tables are usually used only by SAP and not used by customers.

• Secondary indexes cannot be created.

• You cannot use the ABAP/4 constructs select distinct or group by.

• You cannot use native SQL.

• You cannot specify field names after the order by clause.

• Order by primary key is the only permitted variation.

Regards,

Harish

Re: table type

Former Member — Tue, 04 Mar 2008 05:44:50 GMT

hi,

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 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.

Re: table type

Former Member — Tue, 04 Mar 2008 05:45:05 GMT

i)Transparent tables - Exists with the same structure both in dictionary as well as in database exactly with the same data and fields. Both Opensql and Nativesql can be used.

ii)Pool tables & iii)Cluster tables -

These are logical tables that are arranged as records of transparent tables.one cannot use native sql on these tables

(only opensql).They are not managable directly using database system tools.