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dbms_random

dbms_random allows to generate random data. With 10g, there are three random generators in dbms_crypto that produce better random values than dbms_random.

Initialize(val in binary_integer)

Initialize is obsolete. It calls the procedure seed.

Normal

Returns a random number from a normal distribution.

Seed

Seed is an overloaded procedure with one parameter that either takes a binary_integer or a varchar2.
By default, the pakcage is Initialized (seeded) with the current user name, the time (accurate downt to the second) and the current session

Pack

String

dbms_random.string(opt, len);
The function string returns a string whose length is determined by the len argument.
The returned string's characteristics are determined by the opt argument. opt must be a char. The following five options are possible:
'u' or 'U':Upper case alpha characters
'l' or 'L':Lower case alpha characters
'a' or 'A':Upper and lower case alpha characters
'x' or 'X':Upper alpha and numeric characters
'p' or 'P':Any printable character
col u format a10
col l format a10
col a format a10
col x format a10
col p format a10

select 
  dbms_random.string('u', 10) u,
  dbms_random.string('l', 10) l,
  dbms_random.string('a', 10) a,
  dbms_random.string('x', 10) x,
  dbms_random.string('p', 10) p
from
  dual;

U          L          A          X          P
---------- ---------- ---------- ---------- ----------
QRBBMHKILH eyotdrlvms DQQqXImnXt ONU82BQHZS `TKzRQ$[sR

Value

dbms_random.value();
dbms_random.value(low, high);
The function value comes in two specifications: dbms_random.value() and dbms_random.value(low in number, high in number).
If called without parameters, it will return a (pseudo random) number between 0 and 1. This range can be extended to return a (pseudo random) number between a freely choosable lower limit (low) and higher limit(high). 
begin
  for i in 1 .. 20 loop
    dbms_output.put_line (
      i || ': ' ||
      dbms_random.value(0, 10)
    );
  end loop;
end;
/

Terminate

The procedure terminate is obsolete and does nothing (at least in Oracle 9).

Examples

dbms_random is used in my dummy data generator.