How are SQL statements executed in application programs? Are 'application plans' created in this process and stored in the database?
When an application program is executed, ADABAS - unlike other database systems - compiles each SQL statement upon its first execution (parse phase), storing it as a kind of temporary 'application plan' in the database. To accelerate the processing, the internal representation is accessed for each subsequent execution of the statement (execute phase). This internal representation, however, is only stored for the duration of the application program (i.e., until the end of the session).
This facilitates both the adaptation of the 'application plan' to newly created or dropped indexes and the response to modified user privileges. This technique also enables ADABAS to respond immediately to these types of changes in the database structure during the execution of an application without having to terminate and restart the application.