1. Table pool is used for storing large number of unrelated logical tables in one physical table. Table cluster is used for storing small number of related logical tables in one physical table.
3. One record of a table pool represent one record of any one of the pooled table whereas one record of table cluster represent data from one or more records of all cluster tables (If it fits in one page).
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.
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.