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Optimizing Queries for User-Defined Data Types

Queries that access user-defined data types (UDTs) can take advantage of the same performance features that built-in data types use:

In addition, programmers can write the following functions or UDRs to help the optimizer create an efficient query plan for your queries:

The following sections summarize these techniques. For a more complete description of how to write and register user-defined selectivity functions and user-defined cost functions, see IBM Informix: User-Defined Routines and Data Types Developer's Guide.

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