Operator-class functions

An operator class is the set of operators that the database server associates with a secondary-access method for query optimization and building the index. A secondary-access method (sometimes referred to as an index-access method) is a set of database server functions that build, access, and manipulate an index structure such as a B-tree, an R-tree, or an index structure that a DataBlade® module provides.

The query optimizer uses an operator class to determine if an index can be considered in the cost analysis of query plans. The query optimizer can consider use of the index for the given query when the following conditions are true:

An index exists on the particular column or columns in the query.
For the index that exists, the operation on the column or columns in the query matches one of the operators in the operator class that is associated with the index.

For more information about how to optimize queries with UDRs, refer to Optimize a user-defined routine. For more information about how to extend operator classes, refer to Extending an existing operator class.

Tip: If a DataBlade module provides a secondary-access method, it might also provide operator classes with the strategy and support functions. For more information about functions that a specific DataBlade module provides, refer to the user guide for that DataBlade module.