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Editorial Team
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Asked: 2026-05-22T16:48:45+00:00

The project I work on has undergone a transformation at the database level. For

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The project I work on has undergone a transformation at the database level. For the better, about 40% of the SQL layout has been changed. Some columns were eliminated, others moved. I am now tasked with developing a data migration strategy.

What migration methods, even tools are available so that I don’t have to figure out each every individual dependency and manually script a key change when their IDs (for instance) change.

I realize this question is a bit obtuse and open ended, but I assume others have had to do this before and I would appreciate any advice.

I’m on MS SQL Server 2008

@OMG Ponies Not obtuse but vague:

Great point. I guess this helps me reconsider what I am asking, at least make it more specific. How do you insert from multiple tables to multiple tables keeping the relationships established by the foreign keys intact? I now realize I could drop the ID key constraint during the insert and re-enable it after, but I guess I have to figure out what depends on what myself and make sure it goes smoothly.
I’ll start there, but will leave this open in case anyone else has other recommendation.

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  1. Editorial Team

    You should create an upgrade script that morphs the current schema into the v. next schema, applying appropriate operations (alter table, select into, update, delete etc). While this may seem tedious, is the only process that will be testable: start from a backup of the current db, apply the upgrade script, test the result db for conformance with the desired schema. You can test and debug your upgrade script until is hammered into correctness. You can test it on a real data size so that you get a correct estimate of downtime due to size-of-data operations.

    While there are out there tools that can copy data or transforms schema(s) (like SQL Compare) I believe approaching this as a development project, with a script deliverable that can be tested repeatedly and validated, is a much saner approach.

    In future you can account for this upgrade step in your development and start with it, rather than try to squeeze it in at the end.

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