2015-02-09 10:59 GMT+01:00 Marc Balmer <marc@msys.ch>:
> > 2015-02-09 10:37 GMT+01:00 Marc Balmer <marc@msys.ch <mailto:marc@msys.ch>>: > > Currently there are FETCH and the (non standard) MOVE commands to work > on cursors. > > (I use cursors to display large datasets in a page-wise way, where the > user can move per-page, or, when displaying a single record, per record. > When the user goes back from per-record view to page-view, I have to > restore the cursor to the position it was on before the user changed to > per-record view.) > > I have to "manually" keep track of the cursor position, but in some > cases it would definitely be easier to just query the current cursor > position directly from the database and later use "MOVE ABSOLUTE" to > rewind it to that position. That could be achieved e.g. by a > hypothetical "TELL <cursor-name>" command. It does, however, not exist > and I have not found an alternative. Is there a way to query the > current cusros position at all? If not, does a TELL command sound like > a good or bad idea? > > > It sounds like good idea. > > Do we need a new statement? We can implement returning the position to > MOVE statement. It returns a delta, but it can returns a absolute > position too.
On second thought, a new statement is not needed at all. As Heikki noticed in hsi reply, it could either be a new function or have move to return the current position somehow(tm). Or a nw option to move, maybe "MOVE NOT" (don't move the cursor but return it's position?
returning a absolute position in FETCH, MOVE statements has minimal overhead probably, so you can get a current position as side effect of last statement
