🚀 go-pugleaf

A big thanks for your answer !

I learn a lot reading you. 

My fields are all indexed the good way (I think). 

I have made a search in the VCL source code and it appears that it is
dbiOpenCursor that is the slowest call (30 seconds). And not only with
M/D relations, but for each opening. My slowest table has many fields
(30-40) but only 3 records !

I'll study your answer a little more and try again.

Thanks again 

Fr�d�ric GUILLIEN

VHA PC Development wrote:
> 
> Frederic,
>         I'm not sure how much you know about Access so I'm not going to make any
> assumptions.  First, make sure that the Table in Access has a LongInteger
> or Autonumber primary key (avoid textual keys!); second, make sure that the
> table is indexed for ALL link fields; thirdly, if you are using a TQuery,
> make sure that your SQL returns a recordset that has one of the key/indexed
> fields returned within it.
> 
> Now, the way Access does it.  Access uses Rushmore Query Technology which
> allows it to return (for Dynasets or modifiable sets of records) just the
> primary or indexed key value that uniquely identifies a row - if one is not
> available, it creates one or returns the whole row (ssllooww).  Access then
> populates the visible rows on the screen while retrieving the remainder of
> the rows in the background.   Access's way APPEARS to be faster to the user
> but actually takes relatively longer to return the complete recordset due
> to the additional processing involved.  Delphi has to get the whole thing
> THEN begin to display.  The reason for this is that TQuery returns a
> complete recordset based on an SQL string that may include cached editable
> rows.  (At least that is my understanding)
> 
> Access and VB get at the data through the Access Compatibility Layer which
> Delphi has not, to my knowledge, been afforded uh... access to.  MS
> Programs are intimately compatible with themselves.
> 
> On your master/detail form, the recordset object must be requeried,
> refreshed and redisplayed which has to go through all the levels (both
> Delphi objects, ODBC and Access DLL's) back to the data.
> 
> Besides tweaking your recordset objects in Delphi and making sure that
> there are unique indexed keys in access, I can't think of anything else
> that would make the process faster.  I'm going to have to do some research
> to see if I can improve data retrieval times with Delphi using Access
> databases - then I'll share my results.  :)
> --
> 
> =======================================
> codifex@airmail.NOSPAM.net
> bgravitt@vha.NOSPAM.com
> =======================================
> 
> Fr�d�ric GUILLIEN <fguillien@hol.fr> wrote in article
> <352B6ED7.6DC@hol.fr>...
> > Hi,
> >
> > Opening an ACCESS table with Master/Detail links is very very slow.
> > Without the M/D link, the table open correctly : it's acceptable, but
> > when I set the link, it's awfully slow !
> >
> > Do you know where the machine hang with this. I tried the same link with
> > Access and it works well. With VB also.
> >
> > As I forced to choose Delphi to create this part of the program, I don't
> > want the app to be slower than VB first module I developed last year...
> >
> > I hope there is an easy solution.
>