In java, say I have a program which checks for the max value in database and increments it by 1 to create my receipt number.
How could I start my first number as 001 and increment it accordingly.
Thus
int x = rs.get( sql statement for maximum value).
Say x = 001
New number to be inserted back should be 002.
First of all, your variable x is int, so it can't be 001, just 1, but you can make a String to use it elsewhere with formatting:
String formattedX = String.format("%03d", x);
I suppose, "checks for the max value in database" means to get next value for the Primary Key. To do it, you can use a database sequence (read about it here, it's databasespecific so I can't say how to implement it in your case) and everytime you need it, get it's next value. For OracleDB it can be done with this query:
SELECT somesequense.nextval FROM DUAL;
Or you can use a analytics MAX() functions for your Database, example for Oracle:
SELECT MAX(receipt_number) "Maximum" FROM receipts;
And then just increment it in your java code. But it's not a good solution, because it can lead to some problems, when you'll get the same value in several transactions.
