Pooled Tables vs Cluster Tables
Cluster tables and Pooled tables have Many to One relationship with a Table in the database i.e many tables of cluster/pooled tables has one database table. Pool and Cluster table is basically use to store Application Data.
The main difference between Pooled Table and Cluster Table.
- A Table Pool corresponds to a table in the database in which all records from the pooled tables assigned to it are stored. In other words a number of pool table are stored in single table called Table Pool. Several logical data records from different Cluster Tables can be stored together in one physical record in a table cluster. In other wordss many Cluster Table are stored in one single table called Table Cluster.
- A pooled table cannot have the name having more than 10 characters.
- All the key fields of the pooled table must be of character data type (for example, CHAR, NUMC, CLNT). A Cluster 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.
- Table Cluster has primary key but Table pool doesn't.
- In pooled tables, the maximum length of the key field/data fields should not exceed the length of varkey/vardata of the pool respectively.
- In cluster table the records having the same key are stored in a single key in the cluster. If there is an overflow of the data records a continuation record is created with the same table key.
- Table Pool contain large number of table having small data on the other hand Table Cluster holds few numbers of table having large data. For e.g 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.
A pooled table is used to combine several logical tables in the ABAP/4 dictionary.
Pooled tables are logical tables that must be assigned to a table pool when they are defined.
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.