about clusters

[Former Member]

hi all,

could u pls explain me about clusters?

what is clusters?

and how the data will store in clusters?

[Former Member]

Hi Devender,

Here are feww definitions. Hope it helps your understanding.

<b> Cluster table </b>

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.

<b>What is a table cluster?</b>

A table cluster combines several logical tables in the ABAP/4 Dictionary. 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.

<b>What are DATA CLUSTERS ?</b>

You can group any complex internal data objects of an ABAP/4 program together in data clusters and store them temporarily in ABAP/4 memory or for longer periods in databases. You can store data clusters in special databases of the ABAP/4 Dictionary. These databases are known as ABAP/4 cluster databases and have a predefined structure.Storing a data cluster is specific to ABAP/4. Although you can also access cluster databases using SQL statements, only ABAP/4 statements are able to decode the structure of the stored data cluster.

http://help.sap.com/saphelp_nw04/helpdata/en/cf/21f0b7446011d189700000e8322d00/content.htm

Suggest to do search in SDN with key - 'Cluster'

Will get a lot of helpful discussions.

<b>Reward points if this helps.

Manish</b>

[Former Member]

Hi,

CLUSTER:

set of data objects.

Elementary fields , field strings and internal tables etc. will come under data objects.

You can store data clusters in ABAP/4 memory for short time and in database for longer time.

To write data objects from ABAP/4 program to ABAP/4 memory,the following statement is used.

Export f1

f2

to memory id 'table'.

Import f1

f2

from memory id 'table'.

Free memory id 'table'...Cluster will be deleted from the memory.

These cluster databases come into picture to keep the information

relating to a company more secure.

e.g. Payroll, time related data.

e.g. cluster database tables PCL1, PCL2, PCL3 and PCL4.

PCL1 is the database for HR application areas.It contains information

regarding the time recording.

PCL2 contains information regarding payroll accounting.

PCL3 contains applicant data.

PCL4 contains change documents for HR master data.

Cluster rx contains the payroll results for country x according to table

T500l.

The clusters can be called from macros.

RP-IMP-Cn-xx ( n = 1,2,3,4 and xx is cluster)

When macro is used to import data,it is not directly get from database table PCL,

instead it checks for the buffer directory whether it contains it in main memory.

if it is there it takes it from main memory..otherwise it reads from PCL to main

memory and from there to the report.

Standard import programs follow the naming convention RPCLSTxx..xx is cluster.

RP-EXP-Cn-xx ( n = 1,2,3,4 and xx is cluster)

[Former Member]

Hi,

Go the following link:

http://www.sapbrainsonline.com/TUTORIALS/TECHNICAL/ABAP_tutorial.html

Click on ABAP Programming Complete Guide.

Download into your local disk in pdf format.

Goto page no: 361. You will get full details about Clusters.

Regards,

Bhaskar