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How to Use Migration With Entity Framework Core

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How to Use Migration With Entity Framework Core

Learn how to utilize the migrations of Entity Framework Core RC2, complete with screen shots and code, from Jalpesh Vadgama.

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Entity framework core is the lightweight, extensible, and cross-platform version of Entity Framework. After some time, Microsoft had released a new version of Entity Framework RC2. I have written a couple of blog posts about Entity framework code first migration (earlier for Entity framework 6.0). So there was a couple of requests coming for me to write a blog post about Entity Framework Core RC2 migration. So I thought it would be a good idea to give an overview how database migration works in Entity Framework Core RC2. This post will cover a basic scenario where we are going to create the database with existing ASP.NET Identity migration and then we are going to create a new model and have that migration applied in the database.

How to Use Entity Framework Migrations

Let’s get started. To demonstrate entity framework core migrations, I am going to create a sample asp.net core web application like following.

creating-project-core-migration

Once we select asp.net core application, it will appear the following dialog.

web-application-aspnet-core

Now create a sample application. It will basically create a boilerplate code for the asp.net identity and as a part of that it is going to create entity framework migration files under Data –> Migrations folder.

default-migration-entity-framework-core

Here you can find that sample code in GitHub repository given at the bottom. Now we already asp.net identity migration code ready. So let’s have those migrations applied with the following command from NuGet package manager console.

update-database

core-migration-aspnet-identity

Now let’s add a new model “Employee” like the following:

namespaceCoreMigration.Models{
    publicclassEmployee{
        publicintEmployeeId { get; set; }
        publicstringFirstName { get; set; }
        publicstringLastName { get; set; }    }}


As we have employee class, we need to add migration for that. I’m going to create a migration for employee class via the following command.

add-migration AddEmployee

add-employee-migration

It will create “AddEmployee” migration class in Data->Migrations folder.

employee-migration-in-solution-explorer

And here is the code for the migration for the same.

usingMicrosoft.EntityFrameworkCore.Migrations;
usingMicrosoft.EntityFrameworkCore.Metadata;   
namespaceCoreMigration.Data.Migrations{    
    publicpartialclassAddEmployee : Migration    {        
        protectedoverridevoidUp(MigrationBuilder migrationBuilder)        {   
            migrationBuilder.CreateTable(name: "Employees", columns: table => new{
                EmployeeId = table.Column<int>(nullable: false).Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
                FirstName = table.Column<string>(nullable: true), LastName = table.Column<string>(nullable: true)},
            constraints: table => {
                table.PrimaryKey("PK_Employees", x => x.EmployeeId);
                });
            }
        protectedoverridevoidDown(MigrationBuilder migrationBuilder){
            migrationBuilder.DropTable(name: "Employees");
            }    
        }
    }


Now we have our migration class ready, so I am going to run the update-database command as following:

update-database-employee-migration-entity-framework-core

Now let’s check the database again. You can see employee table is there.

database-after-employee-migration

That’s it. It’s very easy. Hope you like it. Stay tuned for more.

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Topics:
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Published at DZone with permission of Jalpesh Vadgama, DZone MVB. See the original article here.

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