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Categories / Oracle PLSQL Tutorial / PL SQL Programming
 

Declaring variables

In PL/SQL, variables must be included in the declaration block before they can be used. There are a number of ways to declare a variable. The most common way is by using a direct declaration, as shown here: declare     variable_name [constant] DATATYPE [DEFAULT value |DEFAULT NULL]; begin     ... The keyword constant means that the variable's value can't be changed in the body of the program. If you declare a variable as a constant, you must assign a default value to it by using the optional DEFAULT value clause. The following shows an example of correct declarations of variables: SQL> declare   2      v_sal   NUMBER;   3      v_name  VARCHAR2(10) DEFAULT 'KING';   4      v_start_dt DATE := SYSDATE; -- same as DEFAULT SYSDATE   5  begin   6      NULL;   7  end;   8  / PL/SQL procedure successfully completed. SQL>