PL/SQL

PROGRAMMING LANGUAGE STRUCTURED QUERY LANGUAGE POPULARLY KNOWN AS PL/SQL.

WHAT IS PL/SQL?

· PL/SQL is Oracle's procedural language extension to SQL.

· PL/SQL allows you to mix SQL statements with procedural statements like IF statement, Looping structures etc.

· PL/SQL is the superset of SQL.

· It uses SQL for data retrieval and manipulation and uses its own statements for data processing.

· PL/SQL program units are generally categorized as follows:

· " Anonymous blocks "

· Stored procedures are Anonymous block

· This PL/SQL block appears within the application.

· In many applications PL/SQL blocks can appear where SQL statements can appear.

· Such blocks are called as Anonymous blocks.

· Stored Procedure This is a PL/SQL block that is stored in the database with a name.

· Application programs can execute these procedures using the name.

· Oracle also allows you to create functions, which are same as procedures but return a value, and packages, which are a collection of procedures and functions

PL/SQL ENGINE:

· Every PL/SQL block is first executed by PL/SQL engine.

· This is the engine that compiles and executes PL/SQL blocks.

· PL/SQL engine is available in Oracle Server and certain Oracle tools such as Oracle Forms and Oracle Reports.

· PL/SQL engine executes all procedural statements of a PL/SQL of the block, but sends SQL command to SQL statements executor in the Oracle RDBMS.

· That means PL/SQL separates SQL commands from PL/SQL commands and executes PL/SQL commands using Procedural statement executor, which is a part of PL/SQL engine