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

Chapter 3 Comparing Static and Dynamic SQL

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An ALLBASE/SQL application can contain both static and dynamic SQL statements. A static statement involves the preparation and storing of a section at preprocessing time and the execution of that stored section at run time. A dynamic statement involves the preparation and execution of a section at runtime. Some statements do not require a section, and they are also classified as dynamic.

Each type of statement has advantages and disadvantages as listed below:

  • A static statement performs more efficiently than the equivalent dynamic statement.

  • In order to execute a static statement, a program module (containing a stored section for the statement) must be installed in each DBEnvironment in which the statement is to run. A dynamically preprocessed statement is portable and can be run in any DBEnvironment without installing a program module.

  • Dynamic statements may be more complex to code than are static statements.

Note that all objects referenced by a statement, whether it is static or dynamic, must be present in the DBEnvironment in which the application is running.

The following are dynamic statements:

  • PREPARE

  • DECLARE CURSOR when used with a CommandName

  • DESCRIBE

  • EXECUTE

  • EXECUTE IMMEDIATE

  • FETCH when used with the USING keyword

  • any statement that does not require a stored section for execution

Any statement that is not coded as a parameter of one of the above statements and requires a stored section in order to execute is a static statement.

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