Friday, January 12, 2024

Block Structure & Variables in PL/SQL| Basics of PL/SQL | PL/SQL

 

Block & Variables

Q : What is Block?

A : It is a unit of code that is to declare a data operation and create a logical operation for database.

syntax:

Declare

Begin

End;

Declare:  Declare section means, we can write the variables.

 

Begin and End: This is the main body of the block Where we can write the Pl/SQL Functions, SQL 

                             Statements, Procedures, packages, Cursors.  

Variables:

These are designated storage spaces inside a block, process, function, or package that are used to temporarily keep data.

 The types of data they can store are limited by a certain data type.

Types of Variables

  1.Types of Numbers:

·       NUMBER: Applied to precise and scaled numerical numbers.

·       INTEGER:Whole integers without decimal places.

·       DECIMAL, REAL, FLOAT: Numbers with floating-point precision.

2. Character and String Types:

·       CHAR: Stores character strings (fixed length).

·       VARCHAR: Stores character strings (Variable length).

·       VARCHAR2: Stores variable-length character strings.

·       CLOB: Large object for storing large amounts of character data.

3.  Date Type:

·       DATE: Stores date and time information.

4.Boolean Type:

·       BOOLEAN: Represents true or false values.

5.  LOB Types:

·       BLOB: Stores binary large objects.

 Example-1:

DECLARE

    l_number             NUMBER := 20;

    l_name            VARCHAR2(100) := 'Ram';

    l_present_date   DATE := SYSDATE;

BEGIN

    dbms_output.put_line('The age of '

                         || l_name

                         || ' is '

                         || l_number

                         || ' until today date '

                         || l_present_date);

END;

 

Example-2:

DECLARE

    l_present_date   DATE;

BEGIN

 
              SELECT   SYSDATE

    INTO  l_present_date

    FROM dual;

   dbms_output.put_line(l_present_date);

END;

  

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