EntityFramework Code First under .net core 1.1

Create a new asp.net core project, and then upgrade the class library referenced by. Net core to 1.1. In this case, you need to manually add a runtimes node under project.json, as follows:

"runtimes": {

"win10-x64": {}

}

Add the following three class libraries (version 1.1) to Nuget at the same time:

Microsoft.EntityFrameworkCore.Design

Microsoft.EntityFrameworkCore.SqlServer

Microsoft.EntityFrameworkCore.Tools

Next, define DbContext, which is used to generate the database, as follows:

Using Microsoft.EntityFrameworkCore;using System.Collections.Generic;using System.ComponentModel.DataAnnotations Namespace EntityFrameworkDemo.Model {/ Database object / public class PermissionContext: DbContext {public PermissionContext (DbContextOptions opt): base (opt) {} protected override void OnModelCreating (ModelBuilder modelBuilder) {/ / confirm that the two fields in the UserRole table are the joint primary key modelBuilder.Entity () .HasKey (u = > new {u.UserID) U.RoleID}) } public DbSet Users {get; set;} public DbSet Roles {get; set;} public DbSet UserRoles {get; set;} / public class User {[Key] public int ID {get; set;} public string UserName {get; set } public string Password {get;set;} public List UserRoles {get;set;} / public class Role {[Key] public int ID {get;set;} public string RoleName {get;set;} public List UserRoles {get;set }} / user role relationship / public class UserRole {public int UserID {get; set;} public int RoleID {get; set;} public User User {get; set;} public Role Role {get; set;}}

At this point, you need to add data concatenated strings to the StartUp.cs to guide the server and database name when automatically generating the database.

Public void ConfigureServices (IServiceCollection services) {var connection = @ "Server=.;Database=PermissionDb;Trusted_Connection=True;"; services.AddDbContext (options = > options.UseSqlServer (connection)); services.AddMvc ();}

Now, Build the project and execute it in the package Manager console (vs menu tools-NuGet package Manager-package Manager console) with two commands:

Add-Migration MyFirstMigration

Used to generate commands, generate C # code for databases and tables

Update-Database

Execute the generated code

An error will be reported when using Add-MigrationMyFirstMigration. There is no required project configuration file (.json) in netcoreapp1.1. When you open the bin directory, you will find that there will be an extra win10-x64 folder under netcoreapp1.1. This is exactly what we manually added in project.json. Open this folder and copy the corresponding .json inside. (this should be when Add-MigrationMyFirstMigration generates code. The default search configuration file does not always result in the path where we manually add runtimes)

Add-Migration MyFirstMigration again after copying.

You will find that a folder Migrations has been added to the project and two files are generated below, which are the instructions needed to generate the database.

Now execute Update-Database again

When the execution is successful, use SQL Server's administrative tools to view the generated database, and the table relationships in the table are entered below: