Pool table & Cluster table

Dear all,
could you please help me out from the below.
How to create pooled tables & cluster tables.
When i am trying to create a table, by default it is showing table category as Transparent table.
Regards
Venkat

hi,
A pool table has many to one relation with the table in the database. For one table in the database there are many tables in the dictionary. Tha table in the database has a diff name than in the table in the data dict, it has diff no of fields and field names are different. A pooled table is stored in the pool at the database level. A table pool is a databse table with a special struct that enables the data of many R3 tables to be stored in it. It can hold only pooled tables
Cluster table are logical tables that must be assigned to a table cluster when they are defined.
Cluster table can be used to store control data they can also used to store temporary data or text such as documentation
Pool table
A database table defined in the ABAP Dictionary whose database instance is assigned to more than one table defined in the ABAP Dictionary. Multiple pool tables are assigned to a table pool in the database. The key fields of a pool table have to be character-type fields. The table pool's primary key consists of two fields: TABNAME for the name of a pool table, and VARKEY for the interdependent contents of the key fields in the corresponding pool table. The non-key fields of the pool table are stored in compressed format in their own column, called VARDATA, of the table pool. The only way to access pool tables is by using Open SQL. Joins are not allowed.
Table Pool
Database table in the database that contains the data of several pool 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.
Table Cluster
Database table in the database that contains the data of several cluster tables.
Note: Never mix up with a database table that has the necessary structure for storing data clusters in database tables and in the shared memory. Those are called INDX-type, with reference to the database table INDX supplied by SAP. Data clusters are groupings of data objects for transient and persistent storage in a selectable storage medium. A data cluster can be processed using the statements IMPORT, EXPORT, and DELETE FROM
Some pooled tables:
T000 Clients
T000C Table for Installing FI-SL Customizing
T000CM Client-specific FI-AR-CR settings
T000F Cross-Client FI Settings
T000G Cross-Client FI-SL Postings
T000GL Flexible general ledger: Customizing check
T000K Group
T000MD MRP at MRP Area Level
T001 Company Codes
T001_ARCH Archive contents short description
T001_CONV Company codes affected by currency convers
T001A Additional Local Currencies Control for Co
T001B Permitted Posting Periods
T001C Valid Posting Periods for Global Companies
T001CM Permitted Credit Control Areas per Company
T001D Validation of Accounting Documents
T001E Company Code-Dependent Address Data
T001F Company code-dependent form selection
T001G Company Code-Dependent Standard Texts
T001I Company Code - Parameter Types
T001J Company Code - Parameter Type Names
T001K Valuation area
T001L Storage Locations
T001M Data on Z5A Foreign Trade Regulations Repo
T001N Company Code - EC Tax Numbers / Notificati
A physical table definition is created in the database for the table definition stored
in the ABAP Dictionary for transparent tables when the table is activated.
The table definition is translated from the ABAP Dictionary to a definition of the particular database.
On the other hand, pooled tables and cluster tables are not created in the database.The data of these tables is stored in the corresponding table pool or table cluster.
It is not necessary to create indexes and technical settings for pooled and cluster tables.
regards,
pritha

Similar Messages

Can we create secondary indexes in pooled and cluster table?

hello all
can we create secondary indexes in pooled and cluster table?

Hi,
Yes, you can.
Refer the below links
[http://www.sap-img.com/abap/the-different-types-of-sap-tables.htm|http://www.sap-img.com/abap/the-different-types-of-sap-tables.htm]
[http://help.sap.com/saphelp_40b/helpdata/en/cf/21f083446011d189700000e8322d00/content.htm|http://help.sap.com/saphelp_40b/helpdata/en/cf/21f083446011d189700000e8322d00/content.htm]
Regards,
SB

Which type of information can be hold by pool and cluster tables

hi experts tell me exactly which type of information hold by pooled and cluster tables
thanks in advance

Hi
I hope, you know that Rewarding with Points for the Useful answers is the SDN policy
Pooled table
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.
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 category. This permits object-by-object storage or
object-by-object access. In order to combine tables in clusters, at
least part of the keys must agree. Several cluster tables are stored in
one corresponding table on the database.
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
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
Reward points for useful Answers
Regards
Anji

Why Inner join or Outer join is not used for Pool or Cluster tables ?

Hi SAP-ABAP Experts .
With Due Regards .
May u explain me why Inner join or Outer join is not useful for Pool or Cluster tables ?
because peoples advised not use Joins for Pool and Cluster tables , What harm will take place , If we do this ?
Best Regards to all : Rajneesh

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.
Pooled and cluster tables are usually used only by SAP and not used by customers, probably because of the proprietary format of these tables within the database and because of technical restrictions placed upon their use within ABAP/4 programs. On a pooled or cluster table:
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.
I hope it helps.
Best Regards,
Vibha
Please mark all the helpful answers

Replicating Pool and Cluster tables in HANA

Hi,
Has anyone been able to successfully replicate the Pool and Cluster tables to HANA? I browsed around but am not able to find any solid material/documents related to the same. Please point me to the same.
yogesh

Hi Yogesh,
Maybe you skiped this one. The sample uses BSEG from cluster RFBLG and it's very well explained by Tobias Koebler
How to enable parallel replication
Regards, Fernando Da Rós

Warnings Pool or cluster table selected to check/collect statistics

Dear all,
I am getting error in in db13 backup.
We are using Sap Ecc5 and
oracle 9i on Window 2003.
Production Server I am facing problem suddenly in db13 the UpdateStatsEnded with Return code:    0001 Success with warnings
BR0819I Number of pool and cluster tables found in DDNTT for owner SAPPRD: 169
BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.EPIDXB
BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.EPIDXC
BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.GLSP
BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.GLTP
BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.KAPOL
BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.KOCLU
BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.M_IFLM
BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.VBCLU
BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.VBFCL
And in db02
Missing in R/3 DDIC 11   index
MARA_MEINS
MARA_ZEINR
MCHA_VFDAT
VBRP_ARKTX
VBRP_CHARG
VBRP_FKIMG
VBRP_KZWI1
VBRP_MATKL
VBRP_MATNR
VBRP_SPART
VBRP_WERKS
Please guide steps   how to build index and Pool or cluster table problem.
Thanks,
Kumar

> BR0819I Number of pool and cluster tables found in DDNTT for owner SAPPRD: 169
> BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.EPIDXB
> BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.EPIDXC
> BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.GLSP
> BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.GLTP
> BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.KAPOL
> BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.KOCLU
> BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.M_IFLM
> BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.VBCLU
> BR0871W Pool or cluster table selected to check/collect statistics: SAPPRD.VBFCL
Upto Oracle 9i the rulebased optimizer was still used for Pool/Clustertables for reasons of plan stability (e.g. always take the index).
To ensure that this is the case, these tables/indexes mustn't have CBO statistics.
Therefore these tables are usually excluded from getting CBO statistics via an DBSTATC entry. You can modify this setting in transaction DB21.
> And in db02
>
>
Missing in R/3 DDIC 11   index
> MARA_MEINS
> MARA_ZEINR
> MCHA_VFDAT
> VBRP_ARKTX
> VBRP_CHARG
> VBRP_FKIMG
> VBRP_KZWI1
> VBRP_MATKL
> VBRP_MATNR
> VBRP_SPART
> VBRP_WERKS
Well, these indexes have been setup just in the database and not (how it is supposed to be) via the SE11. As the indexes have a naming-scheme, that is not supported by the ABAP Dictionary, the easiest way to get away from the warnings is to check which columns are covered by the indexes, drop the indexes on DB level and recreate them via SE11.
Best regards,
Lars

What is the differences between Transparent,Pooled and Cluster tables?

Hello all,
What is Pool table?What is the differences between Transparent,Pooled and Cluster tables?
Regards!
Purna

Transparent table:
Tables can be defined independently of the database in the ABAP Dictionary. The fields of the table are defined together with their (database-independent) data types and lengths.
A table definition in the ABAP Dictionary has the following components:
Table fields: The field names and the data types of the fields contained in the table are defined here.
Foreign keys: The foreign keys define the relationships between this table and other tables.
Technical settings: The technical settings define how the table is created on the database.
Indexes: Indexes can be defined for the table to speed up data selection from the table.
There are three categories of database tables in the ABAP Dictionary.
A physical table definition is created in the database for the table definition stored in the ABAP Dictionary for transparent tables when the table is activated. The table definition is translated from the ABAP Dictionary to a definition of the particular database.
On the other hand, pooled tables and cluster tables are not created in the database. The data of these tables is stored in the corresponding table pool or table cluster. It is not necessary to create indexes and technical settings for pooled and cluster tables.
Pooled table
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.
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.
Regds,
Manohar

Where we can use pooled and cluster tables.

Hi Experts,
I have read all the threads and tutorials. all are telling like the difference between pooled and clulster tables are
Pooled table
It can hold small amount of data ( 10 to 100 records) and large number of tables( 100 to 1000 tables). It has fixed structure like Tabname, Varkey, Datain, Vardata.
Cluter tables
It can hold large amount of data but small number of tables. It is also have fixed strucuter like CLKEY1,CLKEY2 , CLKEY3...., Pageno, Timestamp, Pagelg, Vardata.
But i want which situation we can choose pooled table and which situation we can choose cluster table. In general way or Business way.
Thank you,
Srinivas M
Edited by: Srinivas Marapureddy on May 11, 2010 4:39 PM

>
El Tony wrote:
> Those table to manage big data volume, for example BSEG is a cluster table, this help to database for store the data in little amount. Instead the Pooled Table to store the table in other table, so that this help to database for store the data too but in more little amount.
>
> In Background ABAP to control this, because there are source code that help to show the data complete, but in the databse the data is store with alphanumerics. This is a advantage for the database.
Let me correct you, the data is not stored in alphanumeric but in RAW format in pool & cluster tables.
SAP says pool & cluster tables are created so that data from different tables belonging containing similar kind of data are clubbed together. I am not sure if storing data in RAW format compresses its size but SAP recommends storing business data in transperant tables.
Quote from SAP documentation:
"Data of commercial relevance is usually stored in transparent tables."
If data compression were a significant point SAP would have stored data in table clusters & not in transperant tables.
Comments are welcome.
BR,
Suhas

Lock object for KONV table/Cluster table ??

Hi All,
Is it possible to set Lock/Enqueue cluster tables or in my case table:KONV (KNUMV field) ?.
OSS provided some programs without locks so was hoping if I could add before performing data manipulation.
Regards,
Neeth

Hi Nameeth,
you can use generic lock object E_TABLE with function modules ENQUEUE_E_TABLE, DEQUEUE_E_TABLE for locking and unlocking with parameters table name and key field.
Regards,
Satya

Inforation on Pool tables and cluster tables required.

I want to know about the pool tables and cluster tables like how to create them and how to look the tables associated with the given tables. Like for the table BSEG we have other tables linked BSID etc. I'm new to this concept please guide me.

Pooled Table:
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.
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. You might create a table pool if you need to create hundreds of small tables that each hold only a few rows of data. To implement these small tables as pooled tables, you first create the definition of a table pool in R/3 to hold them all. When activated, an associated single table (the table pool) will be created in the database. You can then define pooled tables within R/3 and assign them all to your table pool.
Pooled tables are primarily used by SAP to hold customizing data.
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.
Table clusters contain fewer tables than table pools and, unlike table pools, the primary key of each table within the table cluster begins with the same field or fields. Rows from the cluster tables are combined into a single row in the table cluster. The rows are combined based on the part of the primary key they have in common. Thus, when a row is read from any one of the tables in the cluster, all related rows in all cluster tables are also retrieved, but only a single I/O is needed.
A cluster is advantageous in the case where data is accessed from multiple tables simultaneously and those tables have at least one of their primary key fields in common. Cluster tables reduce the number of database reads and thereby improve performance.
Restrictions on Pooled and Cluster Tables
1. Pooled and cluster tables are usually used only by SAP and not used by customers, probably because of the proprietary format of these tables within the database and because of technical restrictions placed upon their use within ABAP/4 programs. On a pooled or cluster table:
2. Secondary indexes cannot be created.
3. You cannot use the ABAP/4 constructs select distinct or group by.
4.You cannot use native SQL.
5.You cannot specify field names after the order by clause. order by primary key is the only permitted variation.
For creation of pooled /cluster table, have a look at below link.
http://help.sap.com/saphelp_erp2004/helpdata/en/81/415d363640933fe10000009b38f839/frameset.htm
For creation of table pool /cluster, have a look at below link.
http://help.sap.com/saphelp_erp2004/helpdata/en/81/415d363640933fe10000009b38f839/frameset.htm
Have a look at below link.
http://www.sap-img.com/abap/the-different-types-of-sap-tables.htm
Best Regards,
Vibha
*Please mark all the helpful answers

POOL & CLUSTER TABLEs

Hi Experts,
Can you send me some example tables for pool and cluster tables..
And where exactly you use these tables in real time..
Kindly reply me as early as possible
Thanks in advance
Santosh

Hi santosh,
Go to se11
table DD02L-> Give TABCLASS as POOL or CLUSTER you will get a list of tables
Pooled and Cluster 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 pool or table cluster should be used exclusively for storing internal control information (screen sequences, program parameters, temporary data, continuous texts such as documentation). Data of commercial relevance is usually stored in transparent tables.
Table Pools
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). A pool has the following structure:
Field
Data type
Meaning
Tabname
CHAR(10)
Name of pooled table
Varkey
CHAR (n)
Contains the entries from all key fields of the pooled table record as a string, max. length for n is 110
Dataln
INT2(5)
Length of the string in Vardata
Vardata
RAW (n)
Contains the entries from all data fields of the pooled table record as a string, max. length n depends on the database system used
If a pooled table record is saved, it is stored in the table pool assigned. The name of the pooled table is written to the field Tabname. The contents of all key fields of the pooled table are written as a string to field Varkey and the contents of all data fields as a string to field Vardata. The length of the string stored in Vardata is entered in field Dataln by the database interface.
Due to the structure of a table pool, there are certain restrictions on the pooled tables assigned to it. The name of a pooled table may not exceed 10 characters. Since Varkey is a character field, all key fields of a pooled table must have character data types (for example, CHAR, NUMC, CLNT). The total length of all key fields or all data fields of a pooled table must not exceed the length of the Varkey or Vardata field of the assigned pool.
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. A table cluster has the following structure:
Field
Data type
Meaning
CLKEY1
First key field
CLKEY2
Second key field
CLKEYn
nth key field
Pageno
INT2(5)
Number of the continuation record
Timestamp
CHAR(14)
Time stamps
Pagelg
INT2(5)
Length of the string in Vardata
Vardata
RAW (n)
Contains the entries from the data fields of the assigned cluster tables as a string, max. length n depends on the database system used
The records of all cluster tables with the same key are stored under one key in the assigned table cluster. The values of the key fields are stored in the corresponding key fields of the table cluster. The values of all data fields of the assigned cluster tables are written as a string to the Vardata field of the table cluster. Besides the actual data values, the data string contains information on the structure of the data and which table it comes from. If the string exceeds the maximum length of the Vardata field, a continuation record is written with the same key values. The continuation records for a key are distinguished by their value in field Pageno. The actual length of the string in the Vardata field is stored in the Pagelg field by the database interface.
You need the structural information stored in the ABAP Dictionary to read the data from a pooled table or cluster table correctly. These tables can therefore only be processed using Open SQL with the cluster interface, and not with Native SQL directly in the database.
In Repository informatino SE84 goto ABAP Dictonary -> Other Objects -> Pooled and clustered tables -> And then execute. It will give the list of available pooled/clustered tables.
For further reference check the SAP help document...
http://help.sap.com/saphelp_erp2005/helpdata/en/cf/21ea0b446011d189700000e8322d00/frameset.htm
regards,
keerthi

Generic extractors on pool table and Cluster tables

Good Afternoon all,
Can we create generic extractors on Cluster or pool Table. If yes Let me know how?
I am trying to create a Generic Extractor on BSEC Table but it is not allowing me to do this. It throws error that"Extraction from pool tables and cluster tables is not permitted"
Kindly guide me on this
Thanks,
Vaishali.

Hi
you cannot do generic extraction directly on pooled or cluster tables.
You can create a function module, then you can create a Generic Data source based on this..
Hope it helps,
Thanks,
Teja
Edited by: Teja badugu on Apr 15, 2008 12:24 PM

Does Pool & Cluster tables has the same structure in both Dictionary and Db

------------ Exists with the same structure both in dictionary as well as in database exactly with the same data and fields
a. Pool Table
b. Cluster Table
c. Transparent Table
d. All the above
To my knowledge, I know transparent table has the same structure in both Dictionary and database.
Can anyone tel me the answer for the above question.. whether it is
c. Transparent table
or
d. All the above

Transparent Table:
A physical table definition in the database for the table definition which is stored in the ABAP Dictionary for transparent tables when the
table is activated. The table definition is translated from the ABAP Dictionary to a definition of the particular database.
A transparent table in the dictionary has one to one relationship with a table in the database.
For each transparent table in the data dictionary there is one associated table in the database.The database table has the same name, the same number of fields and fields have same names as the transparent table definition. Transparent tables are used to hold application data. Application data is master data or transaction data used by an application.
e.g. master data - table of customers
Transaction data - order placed by the customers.
Pooled 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 pooledtables are stored.
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.R/3 uses pooled tables to hold large number of very small tables. You might create a table pool if yoou need to create hundreds of small tables that each hold only a few rows of data.
Cluster tables :
Cluster tables contain continuous text, for example, documentation.Several cluster tables can be combined to form a table cluster. Severallogical 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, atleast parts of the keys must agree. Several cluster tables are stored in
one corresponding table on the database.
A cluster table is similar to pool table . It has many to one relationship with the table in the database.
They are used to hold the data from a few(approximatelly 2 to 10) very large tables. They would be used when these tables have a part of their primary keys in common and if data in these tables are all accessed simultaneously.A cluster is advantageous in the case where data is accessed from multiple tables simultaneously and those tables have at least one of their primary key fields in common.Cluster table reduce number of database reads and thereby improves performance.

Diff. Between Pool & Cluster Table

Hi,
Could any just let me know regarding the Basic Diff. B/w
Pool & Clsuter Table.
Thanks & Regards
Irfan Hussain

Hi Irfan,
Pooled Table :-
A pooled table in R/3 has a many-to-one
relationship.
When you look at a pooled table in R/3, you see a
description of a table.
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.
You might create a table pool if you need to create
hundreds of small tables that each hold only a few
rows of data.
Pooled tables are primarily used by SAP to hold
customizing data.
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.
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.
Table clusters contain fewer tables than table pools
and, unlike table pools, the primary key of each
table within the table cluster begins with the same
field or fields.
A cluster is advantageous in the case where data is
accessed from multiple tables simultaneously and
those tables have at least one of their primary key
fields in common.
Cluster tables reduce the number of database reads
and thereby improve performance.
Pooled and cluster tables are usually used only by
SAP and not used by customers, probably because of
the proprietary format of these tables within the
database and because of technical restrictions
placed upon their use within ABAP/4 programs.
Cluster table can only be read and display via your
ABAP program.
For furthur details visit this link...
<a href="http://www.sap-img.com/abap/the-different-types-of-sap-tables.htm">http://www.sap-img.com/abap/the-different-types-of-sap-tables.htm</a>
Best Regards,
Maheswaran.B

Maintaince view creation for a cluster table

Hi friends,
I have created a maintaince view for a cluster table bseg and i have activated it its working fine..
now my problem is i can create maintaince view for mutiple tables if other tables are linked with primary table using foriegn key relationship..
Now can any one tell me is it possible to create maintance view for cluster table with multiple tables as i need a linked table with bseg which iam not able to get... ie : when i click on the relationship tab iam not getting the linked tables for bseg...
now can i create a maintaince view with 2 linked cluster tables..
if so can any one tell me how to create it.
As sap says we can create projection view for cluster and pooled table and we cannot create database view for cluster and pooled tables , but it does not mentioned like that for maintaince view....
I assume we can do it.... as iam trying to create a maintaince view with single cluster table then it shoudl allow me to create for multiple linked cluster tables.... and is it mandatory to maintain TMG for this maintaince view....?
Regards
KUMAR

yes.. ur right inserting values into a cluster table other than standard sap tarnactions is dangerious....
But sap didnot mentioned any where that we cannot maintain data for cluster tables using maintaince view... which it said for database view..that pooled and cluster table cannot be used for database view..
Regards
Kumar

Pool table & Cluster table

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