I added EntityFramework.Migrations (Beta 1) to an existing Code-First app that is going through some changes (for both migration capabilities and more fine-tuning of the tables I am generating from my code-first API) and ran into the GETDATE() scenario.
I was already using a custom initializer class in my DbContext to run SQL scripts to set some fields and create indexes in my database. A handful of my AlterTable scripts are primary just to setup fields with default values(such as certain DateTime fields being set to GETDATE()). I was really hoping EntityFramework.Migrations would have an answer for this since you can easily specify defaultValue, but so far I'm not seeing one.
Any ideas? I was really hoping that doing the following would magically work. (It is 'magic unicorn', after all)
DateCreated = c.DateTime(nullable: false, defaultValue: DateTime.Now)
Unfortunately, and logically, it set my default value to the time when the Update-Database
command was executed.
I recently ran in to this issue in EF6 (since they still haven't fixed it). The easiest way I found to do it without having to manually modify the Migration class is to override the CodeGenerator in your Configuration class.
By creating a class that implements MigrationCodeGenerator and then overriding the Generate method you can iterate through all of the operations and apply what ever modifications you want.
Once your modifications have been made, you can then initialize your the CSharpMigrationCodeGenerator and return its default value.
I hope this helps
Create a migration:
For existing records it will set the datetime when you will run
Update-Database
command, for new records it will be set the datetime of creationAn improvement: check if the constraint exists:
This is the most simple way.
First Add
DatabaseGeneratedOption.Computed
DataAnnotion
to your propertyand now you can modify de
SqlServerMigrationSqlGenarator
, override Genarate method and set theDefaultValueSql = "GETDATE()" or "GETUTCDATE()";
Alternatively if your entities inherit from a common interface you can override the SaveChanges method on the DbContext and set or update properties at that point (great for Created Date and Last Changed Date)
You can use
Usage:
Update 2012-10-10:
As requested by Thiago in his comment, I add a little extra context.
The code above is a migration-file generated by EF Migrations by running
Add-Migration MyMigration
as a command in the package manager console. The generated code is based on the models in the DbContext associated with migrations. The answer suggests that you modify the generated script so that a default value is added when the database is created.You can read more about Entity Framework Code First Migrations here.