VOLATILE or NOT VOLATILE

Indicates to the optimizer whether or not the cardinality of table table-name can vary significantly at run time. Volatility applies to the number of rows in the table, not to the table itself. The default is NOT VOLATILE.

VOLATILE
Specifies that the cardinality of table-name can vary significantly at run time, from empty to large. To access the table, the optimizer will typically use an index, if possible.
NOT VOLATILE
Specifies that the cardinality of table-name is not volatile. Access plans that reference this table will be based on the cardinality of the table at the time the access plan is built. NOT VOLATILE is the default.