Concept
Purpose
The first table specified in a script is called the Primary table for the script. The Primary table should be the table that holds the key data you want to view or manipulate.
Usage
One table can be related to another table by either a predefined or an ad hoc relationship. A table related to the Primary table is called a Secondary table. A table related to a Secondary table is called a Tertiary table, etc. There can be any number of such relationship levels.
When processing the records in a table, the data in another table can be accessed if a relationship exists between these tables. A relational operator (all, any, count of, highest of, lowest of, mean of, or sum of) is used to access the data in the related table.