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Question

От
"Louisa Thue"
Дата:
I have a project where we take an existing Access 97 database, which has
already been divided into
front and back-end files, and converting the backend to a PostgreSQL
database.

My questions to you are:
1.  Is this feasible?
2.  If so, how would the Access front-end talk to the PostgreSQL   back-end?  Using ODBC?
3.  Would this connection be painfully slow?

Thanks



RE: Question

От
Michael Davis
Дата:
1. Yes
2. Using ODBC.
3. In some cases, yes.  In particular, if you use a lot of combo boxes on 
your Access forms and queries, they will be slow.  I took any tables that 
were accessed a lot and updated a little and copied them into Access.  I 
wrote a script that would refresh the local Access copy of these tables 
whenever the server copy of these tables were updated.  This was not an 
easy thing to do but it really helped the performance of many of my Access 
forms.

I hope this helps, Michael

-----Original Message-----
From:    Louisa Thue [SMTP:lthue@navarik.com]
Sent:    Tuesday, June 26, 2001 1:47 PM
To:    pgsql-interfaces@postgresql.org
Subject:    Question

I have a project where we take an existing Access 97 database, which has
already been divided into
front and back-end files, and converting the backend to a PostgreSQL
database.

My questions to you are:
1.  Is this feasible?
2.  If so, how would the Access front-end talk to the PostgreSQL   back-end?  Using ODBC?
3.  Would this connection be painfully slow?

Thanks


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RE: RE: Question

От
Michael Davis
Дата:
I wrote triggers in PostgreSQL to update a new table that I created to 
indicate when a local table has changed (insert/update/delete).  This new 
table contains a row for each local table and the date/time this table was 
last updated.  I also stored this table locally in Access.  I then wrote a 
procedure in Access97 that would compare the local and server copy of this 
table and look for any table that changed.  For each changed table, the 
Access procedure would link to the server table and copy the data from the 
server table to the local table.  I then called this Access procedure every 
time a user opened up the Access application and whenever a user opened any 
significant form.  You could do it for all forms, but I had many forms in 
my application so I chose to implement this only in the most important 
ones.  This was not necessarily easy to do but it worked great.

-----Original Message-----
From:    DI Hasenohrl [SMTP:i.hasenoehrl@aon.at]
Sent:    Wednesday, July 04, 2001 1:32 AM
To:    mdavis@sevainc.com
Subject:    Re: [INTERFACES] RE: Question
<< File: ATT00014.htm >> Hello Michael,
 1. Yes 2. Using ODBC. 3. In some cases, yes.  In particular, if you use a lot of combo boxes on  your Access forms and
queries,they will be slow.  I took any tables that  were accessed a lot and updated a little and copied them into
Access. I wrote a script that would refresh the local Access copy of these tables whenever the server copy of these
tableswere updated.  This was not an easy thing to do but it really helped the performance of many of my 
 
Access forms.
 I hope this helps, Michael
 It seems, that I have the some problem of performance now, you had some 
time ago. So I made the same decision like you and work with local Access 
tables and Server tables. In order to synchronise the server tables with 
the Access tables, I asked the odbc-list, if there is a possibility, to 
send updates or inserts from postgresql-tables to local MsAccess-tables.
 I got the following answer: Don't think you can do this via ODBC. Have a "change" table and update a timestamp in it
whenevera target 
 
table is updated. Then clients can poll once a minute or whatever and see if 
their local timestamp is older than the one in the change table.
 Now, I'm developing this solution and have some problems, how to manage 
the error-handling, realize transactions and so on.... Please can you show me your way to synchronise server tables and
Access
 
tables
 Many thanks in advance Irina