Craig,
we are using autoinc primary keys but in a number of places the user can change the order of the lines or insert a new line in the middle of the invoice. ie. add a comment under an existing line. The primary line keys can't be used for the order.

>What are you using for the Primary Key? If you use an autoinc integer, it'll give you what you need. You could also use a date/time stamp.
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>>We are in the process of converting our systems from VFP databases to SQL databases using VFP for the user interface. Of course we won't be limited to one SQL engine. We are debating if we need to add a sequence number to many of our tables to ensure the order of the retrieved records. It appears that when retrieving records from MySQL that the result record set, when retrieving on one identical key (such as invoice number), is in the same order that the records (such as invoice lines) were inserted. Is this a standard? Can I assume that this is true for other SQL engines or do we need to add a sequence number to be sure of the order?
>>TIA