LocalDB Database Add new field migration process

You will use the Entity Framework code to migrate some changes to the model class for the first time, so the change applies to the database

1. Click the right mouse button on the Movies.mdf file in the app-data folder and select Delete to delete the movie database.

2. from the Tools menu, click Library Package Manager and then Package Manager console .

Prompt for input in Package Manager console window  PM>

-contexttypename MvcMovie.Models.MovieDBContext then click Enter. Mvcmovie is the name of the project.

3. Create a Configuration.cs file in the new Migration folder Rationsmig.

4 . Open the Configuration.cs file. Replace the method in the Configuration.cs file with Seed方 The following code:

Protected Override void Seed(Mvcmovie.Models.MoviedbcontextContext){Context.Movies.AddOrUpdate(I=I.Title, New Movie { Title = "When Harry Met Sally",//field in table ReleaseDate = Datetime.Parse("1989-1-11"), Genre = "Romantic comedy", Price = 7.99M }, New Movie { Title = "Ghostbusters", ReleaseDate = Datetime.Parse("1984-3-13"), Genre = "Comedy", Price = 8.99M }, New Movie { Title = "Ghostbusters 2", ReleaseDate = Datetime.Parse("1986-2-23"), Genre = "Comedy", Price = 9.99M }, New Movie { Title = "Rio Bravo", ReleaseDate = Datetime.Parse("1959-4-15"), Genre = "Western", Price = 3.99M } );  } 
 
 5, create a  dbmigration  class for the initial migration. In the  Package Manager Console  window, enter the command  add-migration Initial  to create the initial migration. The first migration of the code creates another class file 201508270142453_rating.cs in the Migration folder. 
 6,  Rating  property to an existing  Movie Class .    Open the Models\movie.cs file and add  Rating  Property:  
  Movie  mode class that is updated in the application is now more than The schema of an existing database for a  Movie  table is different. Perform the operation again  
  8, open migrations\ Configuration.cs file and add the rating field to each of the movie's pairs like     
      

9. Build the solution, then open the Package Manager Console window and enter the following command:

add-migration Rating。当此命令完成，Visual Studio 会打开类文件中定义新的DbMIgration 派生类，并在Up 的方法，你可以看到代码，创建新列

10. Build the solution, and then enter the command in the Package Manager Console window update-database . Rerun the program and add the new field successfully.

     
 
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LocalDB Database Add new field migration process