Entity Framework Code - the first default data in the database

Question

How do I handle situations in which I need pre-existing data before the application is launched or immediately after creating the database. For example, I have a list of countries in which I would like to load into the database after the first code generation. How to do it?

The application is structured as follows:

Repository > Service > WebMVC

xml is in the WebMVC project.

Answer 1

A custom initializer is created that inherits the DropCreateDatabaseIfModelChanges or DropCreateDatabaseAlways . How:

 public class EntitiesContextInitializer : DropCreateDatabaseIfModelChanges<-YourDbContext-> 

And then you overwrite the Seed method, for example:

 protected override void Seed(YourDbContext context) 

The whole example might look like this:

 public class EntitiesContextInitializer : DropCreateDatabaseIfModelChanges<EntitiesContext> { protected override void Seed(EntitiesContext context) { List<Role> roles = new List<Role> { new Role {Id=1, Title="Admin"}, new Role {Id=2, Title="ProjectManager"}, new Role {Id=3, Title="Developer"} }; // add data into context and save to db foreach (Role r in roles) { context.Roles.Add(r); } context.SaveChanges(); } } 

Edit: after setting this parameter, you must also install the Initializer, as noted by Ladislav Mrnka.

 Database.SetInitializer(new EntitiesContextInitializer()); 

i.e. ..: in Global.asax:

 protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterGlobalFilters(GlobalFilters.Filters); RegisterRoutes(RouteTable.Routes); Database.SetInitializer(new EntitiesContextInitializer()); } 

Remember to add using System.Data.Entity; .....

Answer 2

You must create your own database initializer, obtained, for example, from DropCreateDatabaseIfModelChanges and fill in the data using the overriden Seed method. Then you should use Database.SetInitializer to install a new initializer at application startup. Here is an example (from CTP5) used to create a custom index in a database.

Answer 3

For an example, see the new MVC / Entity Framework tutorial series http://www.asp.net/entity-framework/tutorials#Using%20MVC Both # 1 and # 4 show initialization classes.