HPlogo ALLBASE/SQL Advanced Application Programming Guide: HP 3000 MPE/iX Computer Systems

Chapter 4 Using Parameter Substitution in Dynamic Statements

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When your application uses dynamic processing, parameter substitution offers added flexibility and improved performance. Although you can use this technique in any dynamic processing application involving prepared sections, it could be most useful for applications where the same SQL statement type must be re-executed multiple times using a different set of parameter values each time.

A statement containing dynamic parameters must be dynamically preprocessed at run time by using the PREPARE statement. The dynamic section created can then be executed as many times as required within a given transaction with the option of assigning a different set of dynamic parameter values for each execution and without the overhead of preprocessing each time input values change.

The following paragraphs define dynamic parameters, discuss implementation methods, and provide examples. Topics include:

  • Understanding Dynamic Parameters.

  • Where to Use Dynamic Parameters.

  • Programming with Dynamic Parameters.

  • Using Default Data Types with Dynamic Parameters.

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