Architecture of PL/SQL:

PL/SQL runtime system is a technology that has an engine which executes PL/SQL blocks and subprograms.  An engine can be installed in the Oracle server or in an application development tool like as Reports and Forms. The engine can reside in either of   the two environments:

• Oracle server
• Oracle Tools

These two environments are independent. PL/SQL may be available in Oracle Server but unavailable in tools or the other way around. A PL/SQL engine processes the procedural statements and sends the SQL statements to the SQL Statement Executor in the Oracle Server.

The subsequent figure described this:

Figure: PL/SQL Engine