differnce between view and cluster table

[Former Member]

hi all,

can any one tell me about the difference between vies and cluster table in abap dictionary..

thanks in advance,

ashu.

[sreeramkumar_madisetty]

Hi

Cluster Table :

Cluster tables combine the data from several tables with identical (or almost identical) keys into one physical record on the database.

Data is written to a database in compressed form.

Retrieval of data is very fast if the primary key is known.

Cluster tables are defined in the data dictionary as transparent tables.

External programs can NOT interpret the data in a cluster table.

Special language elements EXPORT TO DATABASE, IMPORT TO DATABASE and DELETE FROM DATABASE are used to process data in the cluster tables.

For more info chk this link:

http://fuller.mit.edu/hr/cluster_tables.html

<b>View : Views are the static link between the Trasparent Table.</b>

Regards,

Sree

[Former Member]

Hi Ashu,

To get clear idea on cluster table check

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

Views are nothing but the Inner join on tables. They do not contain data physically, They contain data only at run time which they derive from the underneath tables.

Regards,

Atish

[Former Member]

hi all,

ithink in views also we will bi combining the two table values in one table.. can u get some clear idea on this..

[Former Member]

HI Ashu,

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.

A clustered and a pooled table cannot be read from outside SAP because certain data are clustered and pooled in one field.

View :

database view is a logical defination of table it does not exists physically in the database. it gets its value from the database depending on its defination. and joins used.

databse view - it is a window to a database table.

Thanks.

[Former Member]

hi,

Cluster Table:

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

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.

View:

Data about an application object is often distributed on several tables. By defining a view, you can define an application-dependent view that combines this data. The structure of such a view is defined by specifying the tables and fields used in the view. Fields that are not required can be hidden, thereby minimizing interfaces. A view can be used in ABAP programs for data selection