Programming Oracle® Triggers and Stored Procedures, Third Edition

11.16. Random Number Generation

You use the DBMS_RANDOM package to generate random numbers. You set the seed with the SEED function, which is overloaded.

PROCEDURE seed(val IN BINARY_INTEGER);
PROCEDURE seed(val IN VARCHAR2);

Two methods for setting a seed are:

dbms_random.seed(123456);
dbms_random.seed(TO_CHAR(SYSDATE,'dd-mon-yyyy hh24:mi:ss');

The function VALUE generates a 38-digit precision number within the range:

0.0 <= value < 1.0

The function definition for a random number is:

FUNCTION value RETURN NUMBER;

The following block illustrates the VALUE function.

DECLARE
    N NUMBER;
BEGIN
    dbms_random.seed(123456);
    N := dbms_random.value;

    -- N will be a number similar to:
    --
    -- 0.92531681298113309873787795771931592618
END;

You can generate ...