SPL is a block-structured language. The first section that can appear in a block is the declaration section. The declaration section contains the definition of variables, cursors, and other types that can be used in SPL statements contained in the block.

Typically, all variables used in a block must be declared in the declaration section of the block. A variable declaration consists of a name that is assigned to the variable and the data type of the variable. Optionally, the variable can be initialized to a default value in the variable declaration.

The following example shows the general syntax of a variable declaration:

name type [ { := | DEFAULT } { expression | NULL } ];
  • name is an identifier assigned to the variable.
  • type is the data type assigned to the variable.

[ := expression ], if given, specifies the initial value assigned to the variable when the block is entered. If the clause is not given, the variable is initialized to the SQL NULL value.

The default value is evaluated every time the block is entered. For example, assigning SYSDATE to a variable of the DATE type causes the variable to have the time of the current invocation, not the time when the procedure or function was precompiled.

The following procedure illustrates some variable declarations that utilize default values consisting of string and numeric expressions.

    p_deptno        NUMBER
    todays_date     DATE := SYSDATE;
    rpt_title       VARCHAR2(60) := 'Report For Department # ' || p_deptno
    	     || ' on ' || todays_date;
    base_sal        INTEGER := 35525;
    base_comm_rate  NUMBER := 1.33333;
    base_annual     NUMBER := ROUND(base_sal * base_comm_rate, 2);
    DBMS_OUTPUT.PUT_LINE('Base Annual Salary: ' || base_annual);

The following output of the above procedure shows that default values in the variable declarations are indeed assigned to the variables.

EXEC dept_salary_rpt(20);

Report For Department # 20 on 10-JUL-07 16:44:45
Base Annual Salary: 47366.55