Using AutoNumbers properly

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by Keri Hardwick, 01 January 1999    (for ALL VERSIONS of Access)

(Q)     In a table I'm using an Autonumber Field as the primary ID.   But if the user creates a new record and closes the form without saving it,   the Autonumber field still increases by one. This creates gaps in the continuity of the primary key field. How can I:

(a)  stop the Autonumber incrementing itself if the record wasn't created; and
(b)  force a renumber of this field to occupy contiguous numbers if I was delete record(s) from the table?

(A)   There is no such thing as a record number in Access.

Records just "are" - a table is a big, unsequenced bucket. Indexes and queries provide order to the records in the bucket.

Autonumber is simply a way to create a unique identifier for each record. It should NEVER be treated as a meaningful piece of data.

If you need a meaningful sequencer (like to assign user numbers), you have to create it and manipulate it yourself. You will need to stop using Autonumber, and create a sequence number that you increment yourself and apply to the record when it is saved.

You can also capture the numbers from deleted records and re-use  them. If, however, you have the possibility of related records using the number as a foreign key - do not reuse old numbers.

Now, for your db to "work" primary keys do not need to be continuous numbers; they just need to be unique - which is why the Autonumber function works like it does.

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