Embedded SQL application packages and access plans

The precompiler produces a package in the database. The package contains access plans selected by the Db2® optimizer for the static SQL statements in your application. You can optionally specify if you also want a bind file generated.

The access plans contain the information required by the database manager to issue the static SQL statements in the most efficient manner as determined by the optimizer. For dynamic SQL statements, the optimizer creates access plans when you run your application.

Packages stored in the database include information needed to issue specific SQL statements in a single source file. A database application uses one package for every precompiled source file used to build the application. Each package is a separate entity, and has no relationship to any other packages used by the same or other applications. Packages are created by running the precompiler against a source file with binding enabled, or by running the binder at a later time with one or more bind files.

The bind file contains the SQL statements and other data required to create a package. You can use the bind file to re-bind your application later without having to precompile it first. The re-binding creates packages that are optimized for current database conditions. You need to re-bind your application if it will access a different database from the one against which it was precompiled.