Assigning Values to Variables with the Assignment Operator

With the assignment operator (:=), you can assign the value of an expression to a variable in either the declarative or executable part of a subprogram.

In the declarative part of a subprogram, you can assign an initial value to a variable when you declare it. The syntax is:

variable_name data_type := expression;

In the executable part of a subprogram, you can assign a value to a variable with an assignment statement. The syntax is:

variable_name := expression;

The following example shows, in bold font, the changes to make to the EMP_EVAL.calculate_score function to add a variable, running_total, and use it as the return value of the function. The assignment operator appears in both the declarative and executable parts of the function. (The data type of running_total must be NUMBER, rather than SCORES.SCORE%TYPE or PERFORMANCE_PARTS.WEIGHT%TYPE, because it holds the product of two NUMBER values with different precisions and scales.)

FUNCTION calculate_score(evaluation_id IN SCORES.EVALUATION_ID%TYPE
                         , performance_id IN SCORES.PERFORMANCE_ID%TYPE)
                         RETURN NUMBER AS
  n_score       SCORES.SCORE%TYPE;
  n_weight      PERFORMANCE_PARTS.WEIGHT%TYPE;
  running_total NUMBER := 0;
  max_score     CONSTANT SCORES.SCORE%TYPE := 9;
  max_weight    CONSTANT PERFORMANCE_PARTS.WEIGHT%TYPE:= 1;
BEGIN
  running_total := max_score * max_weight;
  RETURN running_total;
END calculate_score;