Re-phrasing the question to: If one wanted to use an extended baseX series of number/letters, allowing to have shorter string to represent the larger range(10^28)....how could you do that with Oracle? Thanks, Abdul From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Hans Forbrich Sent: Wednesday, October 15, 2014 2:48 PM To: oracle-l@xxxxxxxxxxxxx Subject: Re: Custom Sequence Generator Given that the documentation states MAXVALUE Specify the maximum value the sequence can generate. This integer value can have 28 or fewer digits for positive values and 27 or fewer digits for negative values. MAXVALUE must be equal to or greater than START WITH and must be greater than MINVALUE. and you only want to use 12 out of the possible 28 digits, what exactly is your concern? /Hans On 15/10/2014 2:28 PM, Ebadi, Abdul wrote: Hi, We have a need to generate a 10 or 12 digit unique key. Anyone have a quick function for this? For example: 435A24C1. We don’t want to use Oracle’s sequences as we are afraid we will run out of unique ones. We need billions of these keys. Thanks, Abdul