Document numbering
When a number is assigned, why two people can never get the same one, and how the format is built.
Document numbers are the one thing on a document that must never repeat and never go missing. BillFlow assigns them at the moment you issue, from a sequence that belongs to each document type, in a way that two people issuing at the same moment cannot collide.
When a number is assigned#
A draft has no number; the editor shows the next one as a placeholder so you know what to expect. When you choose Save & Issue, BillFlow reserves that number under a database lock, advances the sequence and writes the number to the document in one step. A unique index on the organization, the document type and the number is the final guarantee: even a bug could not store two documents with the same number.
Because drafts consume nothing, you can start and abandon as many as you like. Discarding an issued document returns its number to the pool so it can be reused, and a record of the discard stays in Discarded documents.
Setting the prefix and the next number#
Under Settings › Numbering each document type shows its Prefix, its Next number and a Sequence Preview. Change the prefix to match your existing paperwork, or raise the next number when you are moving from another system and want to continue where it left off. You can also give a document a specific number by hand at issue time; a number that is already taken is refused.
How a number is formatted#
Behind each sequence is a format: the prefix, optional zero padding, an optional year and month, the separator between the parts, an optional suffix, and whether the sequence starts again every year or every month. Try the combinations below to see what the next numbers would look like on a given date.
Try it
Numbering preview
Change the format and see the next three numbers the sequence would issue. The formatter is the product's own.
Next three numbers
- INV-3199
- INV-3200
- INV-3201
This sequence never resets (period key all).
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