the idea behind this is as follows
you have a table, where you want to record orders, and probably ANOTHER table of order lines linked to those orders - so you need an ID number to link the tables
SO:
A) use a meaningful ID number as the key in the order table, and use this as the record link (also called the foreign key) in the order lines table
Then - generate the order numbers EITHER
a) manually - entering the order number you want each time
b) allow the sytem to find the next order number in some automatic way
NOW - since using a meaningful key is not always the best policy an alternative approach is
B) use a non-meaningful ID number as the key in the order table, and use this as the record link (also called the foreign key) in the order lines table. This can be an autonumber, and in this case, it is important to understand that this doesnt have to run in any sequence, and indeed a sequence cannot be guaranteed
BUT
you STILL need the same meaningful order number in the orders table, which still has to be instantiated in some way. Its just that NOW this value isnt the foreign key in the order lines table - the autonumber field from the orders table, should be the foreign key. If you inspect the order lines table, you will now see this relatively meaningless number in the order table - not the actual order number
------------------
This latter idea is actually simpler and more efficient for Access - although it involves the slight overhead of managing an extra key on the orders table. (overhead for Access, not for the user)
And that is why a lot of users here, tend to recommend adding an autonumber key to (virtually) all tables -
--------------
NOW - as far as generating the order number you can
a) enter one directly - OR
b) have another table where you store the next number you want to use - OR
c) get the next number by looking up the last number used, and adding one to it.
A lot of people use option c - but this may not be what you want, so idea a or b, may be more appropriate.
if oyur order numbers include letters as well as numbers, its a bit more fiddly, as you cant add 1 to a text value.
