Creating a subfunction v14

The FUNCTION clause specified in the declaration section defines and names a subfunction local to that block.

The term block refers to the SPL block structure consisting of an optional declaration section, a mandatory executable section, and an optional exception section. Blocks are the structures for standalone procedures and functions, anonymous blocks, subprograms, triggers, packages, and object type methods.

The phrase the identifier is local to the block means that the identifier (that is, a variable, cursor, type, or subprogram) is declared in the declaration section of that block and is therefore accessible by the SPL code in the executable section and optional exception section of that block.

FUNCTION <name> [ (<parameters>) ]
RETURN <data_type>
{ IS | AS }
    [ PRAGMA AUTONOMOUS_TRANSACTION; ]
    [ <declarations> ]
  BEGIN
    <statements>
  END [ <name> ];

Where:

• name is the identifier of the subfunction.

• parameters is a list of formal parameters.

• data_type is the data type of the value returned by the function’s RETURN statement.

• PRAGMA AUTONOMOUS_TRANSACTION is the directive that sets the subfunction as an autonomous transaction.

• declarations are variable, cursor, type, or subprogram declarations. If subprogram declarations are included, they must be declared after all other variable, cursor, and type declarations.

• statements are SPL program statements. The BEGIN - END block can contain an EXCEPTION section.

Examples

This example shows the use of a recursive subfunction:

DECLARE
    FUNCTION factorial (
        n           BINARY_INTEGER
    ) RETURN BINARY_INTEGER
    IS
    BEGIN
        IF n = 1 THEN
            RETURN n;
        ELSE
            RETURN n * factorial(n-1);
        END IF;
    END factorial;
BEGIN
    FOR i IN 1..5 LOOP
        DBMS_OUTPUT.PUT_LINE(i || '! = ' || factorial(i));
    END LOOP;
END;

The following is the output:

1! = 1
2! = 2
3! = 6
4! = 24
5! = 120