定期将访问数据库复制到SQL Server

Question

I have an access 2003 database that holds all of my business data. This access database gets updated every few hours during the day.

We're currently writing a website that will need to use the data from the access database. This website (for the time being) will have only read only capabilities. Meaning there will only need to be one way transfer of data (Access -> SQL).

I'm imaging there's a way to perform this data migration from access to SQL server programatically. Does anyone have any links to something I can read about?

If this practice sounds odd, and you'd like to suggest another way to do this (or a situation where data can go both ways (Access -> SQL, SQL -> Access), that's perfectly fine.

The company is going to continue using Access 2003 for their business functionality. There's no way around that. But I'd like to build the (readonly) website on top of SQL Server.

Answer 1

To do the initial data migration and set the SQL Server automatically, I would use the SQL Server Migration Assistant . The only thing you should definitely change that I can think of would be to turn off the Identity property on any columns that have it - to be explained below (MS Access calls Identity autonumber). Once you have your tables loaded, you can set up a dsnless connection to the database (and tables) you just created.

I haven't used the method just linked, but I believe it allows you to use SQL Server authentication to connect to the db. The benefit of using this method is you can easily change which SQL Server instance and/or database your are connecting to for development and testing.

There might be a better, automated way, but you can create several insert queries doing left joins from the primary key of the Access table to the SQL Server table, and putting a WHERE clause that specifies the SQL Server PrimaryKey must be null. This is why you need to turn off the Identity property in the SQL Server tables, so that you can insert the new data.

Finally, put the name of each query in one function, then run the function periodically.

Answer 2

I have used Microsoft's free SQL Server Migration Assistant (SSMA) to migrate Access to SQL Server. The tool is very simple to use. The only problem I have encountered with the tool was overloaded data types when migrating. What I mean by this is a small string will get converted to a NVARCHAR(MAX) in some instances. Otherwise, the tool is very handy and can be reused after setting up a 'profile'.

Answer 3

The strategy you outlined can be very challenging. You could use INSERT queries to copy new Access rows to SQL Server, as described in another answer.

However, if you have changes to existing Access rows, and you also want those changes propagated to SQL Server, it won't be so simple. And it will be more complicated still if you want deleted Access rows deleted from SQL Server, too.

It seems more reasonable to me to use a different approach. Migrate the data to SQL Server once. Then replace the tables in your Access database with ODBC links to the SQL Server tables. Thereafter, changes to the data from within your Access application will not require a separate synchronization step ... they will already be in SQL Server. And you won't need to write any code to synchronize them.

If your concern is that the connections between the web server and SQL Server be read-only, just set them up that way. You can still independently allow read-write permissions for your Access application.