| PL/SQL is a set of procedural extensions to SQL. In particular it allows
you to create multistatement procedures with their own block structure,
condition testing, etc.
With Oracle V7 you can then store these procedures in the database
("stored procedures") and have applications call them to perform database
work. It is thus possible to prevent applications from ever directly
accessing the database, requiring that they use the stored procedures as
a canned database interface.
The current equivalent for Rdb is to write ACMS tasks for your major
database functions and then only allow database access thru those tasks.
The application either invokes those tasks directly (e.g., from ACMS
Desktop applications) or from other ACMS tasks via task-calling-task
capabilities.
Because Rdb has had a stored procedure capability, via ACMS, since V1 we
have had less pressure to add stored procedures directly to Rdb than
other vendors. The general acceptance of stored procedures within
database systems (and the ability to use them in conjunction with
triggers, SQL/Services, etc.) will eventually force us to implement them
in Rdb. An upcoming revision of the PID should have more details.
Hal
|