I think maybe "Normalization" could be one of the best underutilized features of modern database design by most practicing "Database Consultants." Never have I seen such a rule with so many exceptions! Each normalization decision must be prefaced with "It Depends" in every instance. Ah the potential billable time that can be spent with each normalization effort boggles the mind :-)
If the subject record is be looked on as a "history" record documenting the exact circumstances of a "sales" transaction then it is no longer a dynamic entity subject to the variegations of the ever changing data items within the related "master" tables. Therefore, the data items contained in each row of this table should be a permanent reflection of the master tables' data content at an exact point in time and must not remain linked to the related dynamic master tables. (i.e. the subject table is no longer a "transaction" table in the true sense but a static snapshot of a given physical activity. The exact definition of a particular "sales" event and not subject to change. But then again... Fred > -----Original Message----- > From: John Stanton [mailto:[EMAIL PROTECTED] > Sent: Monday, June 18, 2007 9:58 AM > To: sqlite-users@sqlite.org > Subject: Re: [sqlite] Trigger update of multiple columns > > > If you can automatically enter data then you are violating the > normalization rules. Maybe you should get a book on database > design and > become familiar with some of the fundamentals. > > T&B wrote: > > Hi John, > > > >> You have a reference data set which is accessed to get the > current > >> value of reference elements and store transactions to > record events. > >> The transaction trails provide event history. > > > > > > Yes, agreed. > > > >> A price is in the reference data, its value transferred to a > >> transaction is no longer a price, it is a sale which > represents the > >> value of the price at the time the event occurred. > > > > > > Yes. > > > >> How about reading your price data etc and just inserting a > >> transaction into your sales table? > > > > > > Yes, that's what I'm doing. I just want to make it more efficient. > > > > Technically it's the sale_products table (since each sale has many > > products etc), but yes, I want to insert the transactions data > > (product_id, buy, sell, desc) into the sale_products table. > But I want > > a mechanism whereby if I enter the product_id, then the > buy, sell, desc > > columns are auto entered (copied) from their corresponding > row in the > > products table. > > > > Tom > > > > > > > > > -------------------------------------------------------------- > --------------- > > > > To unsubscribe, send email to [EMAIL PROTECTED] > > > -------------------------------------------------------------- > --------------- > > > > > > > -------------------------------------------------------------- > --------------- > To unsubscribe, send email to [EMAIL PROTECTED] > -------------------------------------------------------------- > --------------- > ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
