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SAP tables

Hi,

Can anyone tell me the exact difference between Pooled,Clustered tables & also some table names for each type also.

Regards,

A.Thuyavan.

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  • author's profile photo Former Member
    Former Member
    Posted on Jun 29, 2007 at 06:39 AM

    Hi,

    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.

    1) T040, T040A--pooled

    2) BSEG, BSES---->cluster

    EXAMPLES->

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

    For further reference check the SAP help document...

    http://help.sap.com/saphelp_erp2005/helpdata/en/cf/21ea0b446011d189700000e8322d00/frameset.htm

    cluster-pool-and-transparent-tables

    Regards,

    Vinodh

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  • author's profile photo Former Member
    Former Member
    Posted on Jun 29, 2007 at 06:39 AM

    Hi Thuyavan,

    table pool or table cluster -> data from different tables can be stored in a pooltable

    cluster table basically contains screen sequnces, program parameters etc..

    Regards

    Sarath

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  • author's profile photo Former Member
    Former Member
    Posted on Jun 29, 2007 at 06:45 AM

    Hi

    Table Types

    Standard table:

    The key access to a standard table uses a sequential search. The time required for an access is linearly dependent on the number of entries in the internal table.

    You should usually access a standard table with index operations.

    Sorted table:

    The table is always stored internally sorted by its key. Key access to a sorted table can therefore use a binary search. If the key is not unique, the entry with the lowest index is accessed. The time required for an access is logarithmically dependent on the number of entries in the internal table.

    Index accesses to sorted tables are also allowed. You should usually access a sorted table using its key.

    Hash table:

    The table is internally managed with a hash procedure. All the entries must have a unique key. The time required for a key access is constant, that is it does not depend on the number of entries in the internal table.

    You cannot access a hash table with an index. Accesses must use generic key operations (SORT, LOOP, etc.).

    Index table:

    The table can be a standard table or a sorted table.

    Index access is allowed to such an index table. Index tables can be used to define the type of generic parameters of a FORM (subroutine) or a function module.

    Just have a look at these links:

    http://help.sap.com/saphelp_nw04/helpdata/en/90/8d7304b1af11d194f600a0c929b3c3/frameset.htm

    http://help.sap.com/saphelp_nw04/helpdata/en/74/83015785d811d295a800a0c929b3c3/frameset.htm

    Pooled Tables, Table Pools, Cluster Tables, and Table Clusters

    These types of tables are not transparent in the sense that they are not legible or manageable directly using the underlying database system tools. They are managed from within the R/3 environment from the ABAP dictionary and also at runtime when they are loaded into application memory.Pool and cluster tables are logical tables. Physically, these logical tables are arranged as records of transparent tables. The pool and cluster tables are grouped together in other tables, which are of the transparent type. The tables that group together pool tables are known as table pools, or just pools; similarly, table clusters, or just

    clusters, are the tables which group cluster tables.Not all operations that can be performed over transparent tables can be executed over pool or cluster tables.

    For instance, you can manage these tables using Open SQL calls from ABAP, but not Native SQL.These tables are meant to be buffered and loaded in memory, because they are commonly used for storing internal control information and other types of data with no external (business) relevance. SAP recommends that tables of pool or cluster type be used exclusively for control information such as

    program parameters, documentation, and so on. Transaction and application data should be stored in transparent tables.

    Table Pools

    From the point of view of the underlying DBMS as from the point of view of the ABAP dictionary, a table pool is a transparent table containing a group of pooled tables which, when created, were assigned to this table pool.

    Field Type Description

    TABNAME CHAR(10) Table name

    VARKEY CHAR(n) Maximum key length n =< 110

    DATALN INT2(5) Length of the VARDATA record returned

    VARDATA RAW(m) Maximum length of the data varies according to DBMS

    Table Clusters

    Similarly to pooled tables, cluster tables are logical tables which, when created, are assigned to a table cluster. Therefore, a table cluster, or just cluster, groups together several tables of type clusters.Several logical rows from different cluster tables are brought together in a single physical record. The records

    from the cluster tables assigned to a cluster are thus stored in a single common table in the database.A cluster contains a transparent cluster key which must be located at the start of the key of all logical cluster tables to be included in the cluster. As well, a cluster contains a long field (VARDATA), which contains the

    data of the cluster tables for this key. If the data does not fit into a field, continuation records are created.

    Field Type Description

    CLKEY1 CHAR(*) First key fields

    CLKEY2 CHAR(*) Second key field

    CLKEYN CHAR(*) nth key field

    PAGENO INT2(5) Number of the next page

    TIMESTMP CHAR(14) Time stamp

    PAGELG INT2(5) Length of the VARDATA record returned

    VARDATA RAW(*) Maximum length of the data section; varies according to database system

    Working with Tables

    The dictionary includes many functions for working with tables. There are five basic operations you can perform on tables: display, create, delete, modify, copy. Please do not confuse displaying a table with displaying the table entries (table contents). In order to display a table, it must previously exist; otherwise the system will display an error message in the status bar. For the following example, the table TABNA is used. To display this table, from the main dictionary screen, enter the table name in the Object name

    input field with the radio button selected next to Tables. Then, click on the Display button at the bottom of the screen, or press the F7 function key, or, alternatively,

    select Dictionary object Display from the menu.

    In this screen, you can see table information such as

    ¨ Table type, shown next to the name of the object. In the example, it is a transparent table.

    ¨ Short text description.

    ¨ Name of the user who made the last change, and the date of the change.

    ¨ Master language.

    ¨ Table status. On the screen, you can see this table is saved and active.

    ¨ Development class. For information on development classes, refer to Chap. 6.

    Delivery class, which sets the maintenance group for the table. It controls how tables will behave during client copy procedures, upgrades, and so forth.¨

    Tab. Maint. Allowed flag, which indicates whether you can generate a screen for maintaining table entries.

    ¨Then, on the lower part of the screen, you can see the table fields with all associated characteristics such as:

    ¨ Field name.

    ¨ Key indicator. When set, this field is the primary key, or part of it.

    ¨ Data element.

    ¨ Basic data type.

    ¨ Length.

    ¨ Check table.

    ¨ Short text, describing the field.

    Additional information about the table can be displayed by selecting the corresponding functions from the menu or directly from the application toolbar, such as keys, indexes, or technical settings

    Kishi.

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  • author's profile photo Former Member
    Former Member
    Posted on Jun 29, 2007 at 06:49 AM

    Hi Thuyavan,

    This will help you,

    Go to se11

    table DD02L-> Give TABCLASS as POOL or CLUSTER you will get a list of tables

    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.

    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.

    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 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.

    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.

    http://www.datamanagementgroup.com/Resources/Articles/Article_0106_2.asp

    more info

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

    http://cma.zdnet.com/book/abap/ch03/ch03.htm

    Check this links.

    http://help.sap.com/saphelp_40b/helpdata/en/4f/991f82446d11d189700000e8322d00/applet.htm

    http://www.techinterviews.com/?p=198

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  • author's profile photo Former Member
    Former Member
    Posted on Jun 29, 2007 at 06:59 AM

    standard table : this is the most appropriate type when u r going to address individual table entries using the index .

    pooled tabel - it has many to one relation ship with table in the data base .

    cluster table : it has many to one relation ship with table in the data base , many cluster tables are stored in a single table in the data base called table cluster .

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