Question

I am writing code to migrate data from our live Access database to a new Sql Server database which has a different schema with a reorganized structure. This Sql Server database will be used with a new version of our application in development.

I’ve been writing migrating code in C# that calls Sql Server and Access and transforms the data as required. I migrated for the first time a table which has entries related to new entries of another table that I have not updated recently, and that caused an error because the record in the corresponding table in SQL Server could not be found

So, my SqlServer productions table has data only up to 1/14/09, and I’m continuing to migrate more tables from Access. So I want to write an update method that can figure out what the new stuff is in Access that hasn’t been reflected in Sql Server.

My current idea is to write a query on the SQL side which does SELECT Max(RunDate) FROM ProductionRuns, to give me the latest date in that field in the table. On the Access side, I would write a query that does SELECT * FROM ProductionRuns WHERE RunDate > ?, where the parameter is that max date found in SQL Server, and perform my translation step in code, and then insert the new data in Sql Server.

What I’m wondering is, do I have the syntax right for getting the latest date in that Sql Server table? And is there a better way to do this kind of migration of a live database?

Edit: What I’ve done is make a copy of the current live database. Which I can then migrate without worrying about changes, then use that to test during development, and then I can migrate the latest data whenever the new database and application go live.

Answer 1

I personally would divide the process into two steps.

1. I would create an exact copy of Access DB in SQLServer and copy all the data
2. Copy the data from this temporary SQLServer DB to your destination database

In that way you can write set of SQL code to accomplish second step task

Alternatively use SSIS