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I recently started using LINQ to SQL in my database later for a C# Windows Forms project. Until now, I have been very impressed with how fast I have been able to implement the data access layer. The problem that I am facing is similar to the post from 2008 below

Best way to update LINQ to SQL classes after database schema change

In short, I am struggling to find an efficient solution for updating the LINQ to SQL files after making minor changes to the database such as constraints, foreign keys, new columns, etc...

Thus far, I have merely been deleting the tables in the LINQ to SQL designer and dragging them back onto the designer. However, I now have the need to rename many of the associations in the designer. The problem is that each time I have to re-create the LINQ to SQL files I lose the change that I manually made to the files. Can someone tell me if there are any new solutions and/or methods for solving this problem. The post that I have included as well as many other dated sources of information mentions that SQLMetal and Huagati are good tools. Additionally, I have read that you can manually create your LINQ to SQL files rather than auto-generate them with the designer (this is what I had to do when using Hibernate with Java).

I know that manually creating the domain classes and mapping files will be consuming. I am not familiar with SQLMetal or Huagati. Can anyone recommend the most elegant or preferred way to deal with this issue? I know that I could use Entity Framework but, I have inherited this project and I am under a very tight deadline. I can refactor it to another Framework once I have this phase complete.

Community
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Grasshopper
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2 Answers2

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After much research and reading, I have determined that the best solution for updating my DBML after minor database changes is to manually edit the file. The procedure used to update the DBML is below:

  1. Right-click on the DBML file
  2. Open with XML Editor
  3. Add or change the columns in the affected table
  4. Add or change any associations
  5. Save the DBML
  6. Rebuild the project

This is not ideal but, once it has been done a few times it is pretty painless for the types of changes that I occasionally need to make to the database such as changing data types, adding keys, etc...

McGarnagle
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Grasshopper
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I don't touch dbml or linq2sql generated files because there is risk that my changes would be overwritten. I use only my generated partial classes. When database schema changes I remove old table from dbml-editor and pull new table to it.

Mark Thomas
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  • The only reason that I generally modify the DBML directly is to change association names. Everything else I keep in the extensibility methods. Do you find that you are able to use the association names that linq generates? My problem is that if I have many foreign keys to the same table (i.e. reference data) then all of my associations are name like (RefData, RefData1, RefData2) instead of something more meaningful like OrderStatus, TransactionStatus, etc...where OrderStatus, Transaction status are reference data stored in the same table. – Grasshopper Feb 15 '13 at 22:27