2011/5/4 Merlin Moncure <mmonc...@gmail.com> > Most of the old school accounting systems maintained an invoice line > number. > > > Invoice Line > > -Invoice Number > > -LineNo > > -ItemID > > -qty > > -Price > > The line number started from 1 (the first line on the invoice) on > every unique invoice. This has the added benefit of allowing the > primary key index (invoice_no, line_no) allowing you to pull up the > invoice line records in correct order without requiring an extra sort > and, if you don't need any fields from the invoice, a join. > > Compare the two queries pulling up invoice lines over a range of > invoice numbers. > > merlin >
Thanks, merlin, And in that case, what is "Natural" in LineNo? I would say, with adding LineNo we are creating syntethic/surrogate Key (just instead of 1 surrogate column - it will be Compound key with more columns...)? The same is with all other tables what are "parts" of an Entity, Serial Numbers, Accounting Distribution produced by Invoice...etc etc...
