Programming Oracle Triggers and Stored Procedures (3rd Edition) (Prentice Hall PTR Oracle Series)

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 random numbers within a range. You call the function VALUE and pass the low and high limits. The function definition is:

FUNCTION value(low IN NUMBER, high IN NUMBER) RETURN NUMBER;

The random number returned is within the range:

low <= value < high

The following generates 10 random two-digit integer numbers.

BEGIN dbms_random.seed (TO_CHAR(SYSDATE,'dd-mon-yyyy hh24:mi:ss')); FOR i in 1..10 LOOP dbms_output.put_line(TRUNC(dbms_random.value(10,100))); END LOOP; END;