Strategy functions are functions that users can invoke within a DML statement to operate on a specific data type. The query optimizer uses the strategy functions to determine whether a given index can be used to process a query.

If a query includes a UDF or a column on which an index exists, and if the qualifying operator in the query matches any function in the STRATEGIES clause, then the query optimizer considers using the index for the query. For more information on query plans, see your HCL OneDB™ Performance Guide.

When you create a new operator class, the STRATEGIES clause identifies the strategy functions for the secondary-access method. Each strategy specification lists the name of a strategy function (and optionally, the data types of its parameters). You must list these functions in the order that the secondary-access method expects. For the specific order of strategy operators for the default operator classes for a B-tree index and for an R-tree index, see HCL OneDB User-Defined Routines and Data Types Developer's Guide.