How to use dbms_random to generate an always-changing string

For a demonstration of Flashback Data Archive, I had to create a daily update to a column in a test table.

The following function did the trick:

select dbms_random.string( 'L',dbms_random.value(10,30) ) from dual;

by returning strings similar to jsytbbtmxrusgmlz or gilqpizjaislueuocqlxydpngtup

"L" is an optional paramter to the STRING function, stating what type of string that should be produced. "L" means "always lowercase".

The numbers 10 and 30 in the value () function returns a string between 10 and 30 characters in length.

Other types of strings you can generate are:

• 'u', 'U' - uppercase alpha characters
• 'l', 'L' - lowercase alpha characters
• 'a', 'A' - mixed case alpha characters
• 'x', 'X' - uppercase alpha-numeric characters
• 'p', 'P' - any printable characters

Oracle-Base contains an excellent article about dbms_random.