Preparing and Executing the Program › Creating the Access Module

Creating the Access Module

An access module is the executable form of the SQL statements that a program issues. When you create an access module, you also invoke the optimizer. The optimizer automatically determines the most efficient access to the data requested by the SQL statements. CA IDMS stores the access strategy in the access module.

How You Create an Access Module

You create an access module with an SQL statement, CREATE ACCESS MODULE. If you accept all defaults, the access module you create:

• Is qualified with the name of the default schema for the user session
• Is stored in the DDLCATLOD area of the application dictionary to which you are connected
• Is created as version 1 if no access module of the same name and version exists in the dictionary
• Has no schema-name mapping to replace existing table or view qualifiers in SQL statements in the RCMs that the access module contains
• Is defined with AUTO RECREATE ON, which means that the DBMS will attempt to re-create the access module at runtime if a change has been made to the definition of a table accessed the module or if the RCM has been re-created since it was included in the access module
• Is defined with VALIDATE ALL, which means that the DBMS will check the definition for each table in the access module before executing the first statement in the access module
• Will execute with a default isolation of cursor stability and allow a transaction to perform updates
• Will execute with a ready mode of shared retrieval on all areas it accesses