Purchase order number generator
A short, unique number is the whole point of a PO. Set the pattern once. Halden uses it the next time you start an order, and advances it when you file that number.
Next eight numbers
Filing an order whose number matches the next value moves the counter. A hand-typed number does not. Cancelled numbers stay cancelled.
Date-only numbers collide the moment two people order on the same morning. A prefix plus a year plus a sequence does not. Department prefixes such as OPS or MKT are fine if they stay short. The longer essay on why this matters is in how to write a purchase order.
Questions
What happens when I change the next number?
The next order that uses a generated number takes that value and then moves the counter forward by one. Numbers already filed do not change.
Can I put a department in the number?
Yes. Use a short prefix such as OPS or MKT. Keep it brief so the number still fits on a packing slip and in an email subject.
Should I reuse a number from a cancelled order?
No. Mark the order cancelled and let the sequence continue. Reusing a number is how two bills get attached to one commitment.