as I already mentioned, if you use a TClientdataset, you can use an ftinternalcalcfield and it's just like an ftCalcfield that you can treat like an ftDatafield. That would seem to be what you are looking for. Dave
--- On Fri, 10/24/08, Ian Stewart <[EMAIL PROTECTED]> wrote: From: Ian Stewart <[EMAIL PROTECTED]> Subject: [delphi-en] Re: DBGrid and calculated fields To: [email protected] Date: Friday, October 24, 2008, 1:05 AM Thanks for everyone's help. Tom gave me an idea of using a previous balance field, which I am currently looking into. Speed is really important, so using a previous balances could be really useful. I will need to add the Balance Field as a physical column rather than a calculated one - something I wanted to avoid, but it will also solve other related issues I have too. Glen, I had already looked into using a StringGrid but it's a lot of work getting other parts of the application to work (eg. OnDataChange etc), but thanks for the reply anyway. Regards, Ian --- In [EMAIL PROTECTED] ps.com, "Glenn B. Lawler" <[EMAIL PROTECTED] .> wrote: > > Ian, > > >I have a problem with a project I am working on. I have a database > >table containing financial transactions: > > > >id account date description amount_in amount_out > > > >I filter the table based on things like account, date ranges etc and > >then show the results in a DBGrid. The user can click on a column to > >change the sort. I need to show the current balance on each row so: > > > >balance = previous_balance + (amount_in - amount_out) > > > >This isn't a big problem until the user scrolls the grid or changes > >the sort field, then the balance column changes as the balance on the > >previous row is wrong. > > If all you want to do is display the output in the grid without the need to > change the data, I would just use a TQuery and TStringGrid to display > the data. Your loop that adds rows to the grid could calculate the balance > any way you want. If users need to change sort order, you can write your > own code to handle clicks on the top row and either sort the loaded grid > or just change the ORDER BY in the SQL and reload. > > Glenn Lawler > www.incodesystems. com > [Non-text portions of this message have been removed]
