How to make a reference no. series

Question

Hello guys!
I need some suggestions or ideas that you may provide with something that I need to do.
<b>SITUATION</b>
What I need to do is this: Create a reference no. series for all documents that I will post.
For example, I will post a doc. with SAP doc num of 1900000001, it will have a ref. no. of RC-0001. If I will post another doc. and for example the SAP doc. num is 1800000275, it will have a ref. no. of RC-0002.
But I do not want to edit standard program and tables, so what I will do is create a table named ZRCDOCS with fields REFNO and BELNR column (that is my ref. no. and SAP doc. no., respectively. I know I should put other data but this is the critical fields).
Then, create a program where I can enter the SAP doc. no. then when I execute, the program will automatically create a ref. no. by incrementing the last ref. no. created (if last no. is RC-0003, next no. is RC-0004).
<b>PROBLEM</b>
I have no problem with creating tables. My problem is the logic in creating the ref. no. series...
As much as possible, I want to give a specific question, but all I can think of asking is: How do I do this? Haha.
Thanks a lot guys! _

Answer 1

in your program read the last record updated to database table (ZRCDOCS) and then increment the no. for RC-XXXX
How to read the last record?
option 1. store updated date time in the table and read the latest record based on that
option 2 store a simple serial number (may be int4 type ) and read the max of that (select max)
Raja