[AccessD] Data from Informix to Access - dirty reads?

Tom Bolton tom.bolton at donnslaw.co.uk
Thu Jan 27 04:57:05 CST 2005


Mark (and Jim)

Sorry for the delay, had a bit on yesterday.  There are indeed ADO/OLEDB
drivers for Informix, a colleague has installed one but is having a little
difficulty with the connection string.  Try http://www.connectionstrings.com


Mark - instead of using APPEND queries, would it not be any faster to pull
the data from Informix in an ADO recordset - I'm doing this via ODBC as this
is how our Terminal Servers are set up >:¬( - then open a DAO recordset on
your Access table, and loop round in a do...while copying the records from
one to the other?  Jim has an excellent link explicitly explaining how to do
just this.  However, I've a sneaking suspicion that he's right, and ODBC is
at the bottom of your woes - definitely worth exploring OLEDB, as methinks
ODBC is a little old-hat these days.

It might just be me (ASP/Oracle/SQL Server background) but I like to try and
avoid letting Jet anywhere near anything that's not solely concerned with
Access FE tables (for which, of course, it's excellent).

Cheers
Tom


-----Original Message-----
From: Jim Lawrence [mailto:accessd at shaw.ca] 
Sent: 27 January 2005 04:48
To: 'Access Developers discussion and problem solving'
Subject: RE: [AccessD] Data from Informix to Access - dirty reads?

Hi Mark:

Your bottle-neck is ODBC. The only way around that is if there is a direct
ADO-OLE equivalent. I am sure there are ADO drivers for every version of
Informix...check these out:

http://www.gold-software.com/LuxenadbExpressdriverforInformixPro-review9342.
htm (ADO type driver... shareware.

You can download the driver from IBM at:
http://www.ibm.com/products/finder/us/en/finders?pg=ddfinder

To then use it the code is something like this:

Dim objConn As ADODB.Connection
Dim gsConnectionString as String

gsConnectionString = "Provider=Ifxoledbc;Password=pass; Persist Security
Info=True;User ID=user;Data Source=market_report;"

objConn.connectionstring = gsConnectionString 
objConn.Open

HTH
Jim


-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Mark A Matte
Sent: Tuesday, January 25, 2005 6:49 AM
To: accessd at databaseadvisors.com
Subject: RE: [AccessD] Data from Informix to Access - dirty reads?

Hello All,

Every week I do pulls from Informix to A97 using ODBC.  1 of my pulls now is

around 1 million records.  I use temp tables and append queries.  This can 
take a few hours.  Some of the replies in this thread imply there is a much 
'better/faster' way.  Without changing versions of Access...is there a way 
to 'tweak'/'speed up' this data pull?

Thanks,

Mark

>From: Roz Clarke <roz.clarke at donnslaw.co.uk>
>Reply-To: Access Developers discussion and problem 
>solving<accessd at databaseadvisors.com>
>To: "'Access Developers discussion and problem 
>solving'"<accessd at databaseadvisors.com>
>Subject: RE: [AccessD] Data from Informix to Access - dirty reads?
>Date: Tue, 25 Jan 2005 09:52:19 -0000
>
>Informix doesn't support XML afaik ><
>
>We did think about this as a way around connection issues for SQL Server
>when we thought that we would have our main db replicating to SQL Server
>rather than Informix - our recordsets are going to be up to about 50k rows 
>I
>think. I don't know how XML would perform with that volume of data but it's
>academic for now.
>
>Roz
>
>-----Original Message-----
>From: John W. Colby [mailto:jwcolby at colbyconsulting.com]
>Sent: 24 January 2005 20:58
>To: 'Access Developers discussion and problem solving'
>Subject: RE: [AccessD] Data from Informix to Access - dirty reads?
>
>
>How much data?  Can it export it to an XML file in a location where your fe
>can use it?  XML has a high overhead but can be useful in cases like this.
>
>John W. Colby
>www.ColbyConsulting.com
>
>Contribute your unused CPU cycles to a good cause:
>http://folding.stanford.edu/
>
>-----Original Message-----
>From: accessd-bounces at databaseadvisors.com
>[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Roz Clarke
>Sent: Monday, January 24, 2005 10:23 AM
>To: 'Access Developers discussion and problem solving'
>Subject: [AccessD] Data from Informix to Access - dirty reads?
>
>
>Hi all
>
>
>We have a bit of a problem with getting data out of our Informix server
>since we recently turned on transaction logging for replication. When
>extracting data with an Access XP MDE using pass-through queries, Access
>locks entire tables in the Informix database, which causes transaction
>errors and makes the Informix database scarily unstable.
>
>Our Informix suppliers told us that the way to avoid these locking issues
>was to set the connection to 'dirty read' before running the SQL. However,
>Access cannot execute 2 statements in a pass-through query and it does not
>hold the connection open between the execution of 1 statement and the next.
>Thus when the query is processed the 'dirty read' setting is no longer in
>effect.
>
>We have been racking our brains trying to come up with a workaround. Some
>further options that we have considered are:
>
>*	Stick the data in a temp table in Informix. This is no good because
>the temp table is destroyed automatically when the connection is closed and
>there's no way to make it persist long enough to bind it to a report.
>*	Use a view in Informix. This is no good because views in Informix
>cannot be set read-only.
>*	Create a permanent table in Informix and destroy it when finished
>with it. This is far from ideal because Informix does not support SELECT
>INTO and therefore a table would have to be explicitly constructed with
>names columns etc. We really need the system to be flexible so that the
>queries can be easily changed.
>*	Use an ADO recordset. This is a PITA because you cannot bind a
>report to a recordset in an MDE and we cannot build the report on the fly -
>we are a Terminal Services site so we will have up to 20 users in one FE.
>*	Create a table in Access and destroy it when finished with it. Can't
>think of a better way to induce bloating...
>
>Has anyone faced this kind of problem before? Any bright ideas? Our
>foreheads are starting to bleed...
>
>TIA
>
>Roz (and Tom)
>
>
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