PLSQL

PL/SQL is Oracle Corporation's procedural extension to SQL. It adds procedural language features to the SQL language and is tightly integrated with Oracle Database, allowing writing programs that run inside the database server. PL/SQL code is stored and executed as database objects, and can call SQL statements directly from within the language. Programs are built from blocks consisting of an optional declaration section, a begin section, an exception-handling section, and an end.

Key features include variables and strongly typed data types (NUMBER, VARCHAR2, DATE, BOOLEAN, and others), records and collection types, and full modularization constructs such as procedures and functions. The language provides robust control flow with IF, CASE, LOOP, WHILE, and FOR statements, as well as explicit and implicit cursors and a comprehensive exception-handling mechanism with predefined and user-defined exceptions. It also supports packages to group related units, triggers to react to database events, and anonymous blocks for ad-hoc scripts. For performance and flexibility, PL/SQL offers dynamic SQL via EXECUTE IMMEDIATE and the DBMS_SQL package, and bulk processing features such as BULK COLLECT and FORALL to minimize context switching when operating on large data sets.

Deployment and use: PL/SQL units are compiled and stored in a schema as procedures, functions, packages, and triggers. They can be called from SQL or from other PL/SQL units, enabling server-side logic that reduces round-trips to the client and can enforce business rules close to the data. Error handling via exceptions helps manage runtime errors and ensures consistent behavior across calls.

Development and ecosystem: Common development environments include Oracle SQL Developer and third-party tools such as TOAD. PL/SQL is Oracle's proprietary extension and is not part of the ANSI SQL standard. Other database systems have analogous languages, such as PL/pgSQL in PostgreSQL and T-SQL in SQL Server. Typical use cases include data validation and transformation, complex business logic, batch processing, and event-driven automation via triggers.