Entity Framework Code First migrations and the [StringLength] annotation

Recently I needed to change my model so that a field would be checked for uniqueness. I eagerly added the [StringLength(3)] and [Index(IsUnique = true)] annotations to the model and ran Add-Migration and Update-Database. Close, but no cigar unfortunately. Update-Database kept throwing the following error: System.Data.SqlClient.SqlException (0x80131904): Column ‘IsoCode’ in table ‘dbo.CurrencyModels’ is of a […]

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Entity Framework: How to delete your old database and start fresh with a new one

In a previous post I explained how to recover after deleting a Entity Framework database. In this post we’ll see the proper way to recreate the database in Entity Framework: Careful before you start, make sure you’ve got source-control or back-ups of the code in the Migrations folder. When you delete the Migrations folder, you’re […]

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Entity Framework and the error: Cannot attach the file ‘xxx.mdf’ as database ‘xxx’

Say you’re working on a project that’s using Entity Framework to manage the database storage in a SQL Server Express installation. If you delete the .mdf file you’ll keep on getting the error” Cannot attach the file ‘xxx.mdf’ as database ‘xxx’. To solve it, in visual studio go to the Package Manager console and run […]

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