Block Type in PL/SQL

In Oracle PL/SQL, there are several types of blocks, each with its own specific purpose and characteristics. These block types include:

Anonymous Blocks:

Anonymous blocks are unnamed PL/SQL blocks that are not stored in the database. They are typically used for ad-hoc tasks, testing, or one-time operations.

An anonymous block starts with the BEGIN keyword and ends with the END; keyword.

BEGIN

   -- PL/SQL code here

END;

Named Blocks:

Named blocks are PL/SQL blocks that have a name and are stored in the database. They can be called from other PL/SQL blocks or applications.

Named blocks include stored procedures, functions, and packages.

CREATE OR REPLACE PROCEDURE my_procedure AS

BEGIN

   -- PL/SQL code here

END my_procedure;

Stored Procedures:

A stored procedure is a named PL/SQL block that can accept parameters and perform a specific task or set of tasks when called.

Stored procedures are typically used for modularizing and encapsulating business logic within the database.

CREATE OR REPLACE PROCEDURE my_procedure (

   parameter1 IN NUMBER,

   parameter2 OUT VARCHAR2

) AS

BEGIN

   -- PL/SQL code here

END my_procedure;

Functions:

A function is similar to a stored procedure but returns a single value. It can be used in SQL statements and expressions.

Functions are defined using the FUNCTION keyword.

CREATE OR REPLACE FUNCTION my_function (parameter1 IN NUMBER)
    RETURN NUMBER
AS
    result   NUMBER;
BEGIN
    -- PL/SQL code here
    RETURN result;
END my_function;

Packages:

A package is a way to group related procedures, functions, variables, and cursors together into a single, organized unit.

Packages have a specification (header) and a body, and they are stored in the database.

CREATE OR REPLACE PACKAGE my_package

AS

    PROCEDURE procedure_in_package;

END my_package;

CREATE OR REPLACE PACKAGE BODY my_package

AS

    PROCEDURE procedure_in_package

    AS

    BEGIN

        -- PL/SQL code here

        END procedure_in_package               ;

END my_package;

Triggers:

A trigger is a PL/SQL block that is automatically executed in response to specific database events, such as INSERT, UPDATE, or DELETE operations on a table.

Triggers are used for enforcing data integrity, logging changes, and automating tasks.

CREATE OR REPLACE TRIGGER my_trigger

    BEFORE INSERT

    ON my_table

    FOR EACH ROW

BEGIN

    -- PL/SQL code here

END my_trigger;

Understanding the different types of PL/SQL blocks and their purposes is essential for effective database development and management in Oracle. Each block type serves a specific role in building robust and maintainable database applications.