katerina-p
asked on
Access front-end and MySQL and Access(Jet) back-ends
Hi All,
System is outgrowing Access's db limitations – 34 back end databases @ 20Gb, and with single tables approaching 1.8Gb it’s time to change! Also more interested in the increased security, stability and multi-user capabilities. Hoping to get performance improvements too as some queries are taking a fair while to process.
I still intend to use Access as a front end, and migrate the back-ends over to MySQL – probably in stages, and starting with an important main 1.8Gb table/db. I appreciate this is a well-asked about area, but I have a few questions which I can’t seem to understand properly and would appreciate answers and any general discussion/advice. I know how to export the Access/JET dbs to MySQL in general.
1. Is using MySQL with Access as simple as linking the MySQL dbs through the External Data->Import->ODBC instead of linking to the Access dbs? (I doubt it!)
2. At the moment (almost)all data editing etc in VBA is done through DAO:
Dim dbs as DAO.Database
Dim rst as DAO.Recordset
Set dbs = CurrentDB
Set rst = dbs.OpenRecordset(x)
Will this be a problem//still work?
3. Various queries and VBA functions on datasets have functions which are Access-specific (CInt, etc). Will these still work or will the MySQL equivalents have to be used?
4. As mentioned, currently spread across 34 Access/JET back ends for space and organisational reasons. Should the data be kept in a single MySQL db/multiple/doesn’t matter?
5. Will there be any problem working an Access front end with backends in both Access/Jet and MySQL, considering queries will be using tables from both
I’m sure there are more / any general advice appreciated!
Thanks in advance.
Katerina.
System is outgrowing Access's db limitations – 34 back end databases @ 20Gb, and with single tables approaching 1.8Gb it’s time to change! Also more interested in the increased security, stability and multi-user capabilities. Hoping to get performance improvements too as some queries are taking a fair while to process.
I still intend to use Access as a front end, and migrate the back-ends over to MySQL – probably in stages, and starting with an important main 1.8Gb table/db. I appreciate this is a well-asked about area, but I have a few questions which I can’t seem to understand properly and would appreciate answers and any general discussion/advice. I know how to export the Access/JET dbs to MySQL in general.
1. Is using MySQL with Access as simple as linking the MySQL dbs through the External Data->Import->ODBC instead of linking to the Access dbs? (I doubt it!)
2. At the moment (almost)all data editing etc in VBA is done through DAO:
Dim dbs as DAO.Database
Dim rst as DAO.Recordset
Set dbs = CurrentDB
Set rst = dbs.OpenRecordset(x)
Will this be a problem//still work?
3. Various queries and VBA functions on datasets have functions which are Access-specific (CInt, etc). Will these still work or will the MySQL equivalents have to be used?
4. As mentioned, currently spread across 34 Access/JET back ends for space and organisational reasons. Should the data be kept in a single MySQL db/multiple/doesn’t matter?
5. Will there be any problem working an Access front end with backends in both Access/Jet and MySQL, considering queries will be using tables from both
I’m sure there are more / any general advice appreciated!
Thanks in advance.
Katerina.
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Quick response:
1 yes
2 yes (works with no problems)
3 yes - no need for equivalents
4 Can't see why not be as you prefer. You need to try.
5 Generally No
1 yes
2 yes (works with no problems)
3 yes - no need for equivalents
4 Can't see why not be as you prefer. You need to try.
5 Generally No
ASKER
Thanks. Will there be a performance increase linking to/using MySQL instead of Access/Jet?
ASKER
I've exported the [main] table to a local MySQL db, set up the PK and indexes. Linked to it in Access via ODBC.
I noticed huge delays opening the table, and I've run a quick query:-
Dim dbs As DAO.Database
Dim rst As DAO.Recordset
Set dbs = CurrentDb
Set rst = dbs.OpenRecordset(x)
rst.MoveFirst
Do While Not rst.EOF
rst.MoveNext
Loop
rst.Close
For the table in a local Access/Jet db, this takes 1 second. For the same table in a local MySQL db, it takes 50s! Why would this be?
Thanks.
I noticed huge delays opening the table, and I've run a quick query:-
Dim dbs As DAO.Database
Dim rst As DAO.Recordset
Set dbs = CurrentDb
Set rst = dbs.OpenRecordset(x)
rst.MoveFirst
Do While Not rst.EOF
rst.MoveNext
Loop
rst.Close
For the table in a local Access/Jet db, this takes 1 second. For the same table in a local MySQL db, it takes 50s! Why would this be?
Thanks.
ASKER
I expect table (and hence database) sizes of up to 20Gb+, and I understand SQL Server Express has a limit (4/10Gb?) so that rules that out.
I'm aware in general of the function differences - when running a query in Access, will I have to ensure that queries on Jet tables use Access functions and queries on MySQL tables use MySQL functions? (As queries will intially pull from both Access/Jet and MySQL, this would mean that different functions in the same query depending on the table that the field is in?)
hnasr, thanks for your time, but my points 2, 3, and 4 had two questions so I'm unsure to which you were answering!
I've seen people establishing ODBC connections to MySQL in VBA - why would this need to be done if you can link the ODBC tables and use DAO/ADO?