Create migration

Create migration

Use the below CLI command to create a migration which will intern create the database, the tables and the required columns in it as per the model we created

Add a migration

dotnet ef migrations add InitialCreate

We should now be able to see a migrations folder and a few files in it as shown

If we open the first file inside the migrations folder, we should see generated code which looks like this

public partial class InitialCreate : Migration
{
/// <inheritdoc />
protected override void Up(MigrationBuilder migrationBuilder)
{
    migrationBuilder.CreateTable(
        name: "Students",
        columns: table => new
        {
            Id = table.Column<int>(type: "int", nullable: false)
                .Annotation("SqlServer:Identity", "1, 1"),
            Name = table.Column<string>(type: "nvarchar(max)", nullable: false),
            IsEnrolled = table.Column<bool>(type: "bit", nullable: false)
        },
        constraints: table =>
        {
            table.PrimaryKey("PK_Students", x => x.Id);
        });
}

So, what exactly happened in the migration?

• First, the migration command searched our project for a file or a class which derives from DbContext

• once it found that it looked into the contents, especially a property or a set of properties of type DbSet<T>

• It understood that they are our model files, and it needs to create database tables for the models by further looking at the properties of the model, which is Student in our case

• It further created the C# code required to programmatically create them

• It has also done the mapping of C sharp data types to their respective SQL Server column types

Entity framework has also identified the Id property of student class to be the primary key for the to-be -created Student table. This is based on conventions which we can always override as and when required!

Apply the migration

At this stage we have no database or tables created we can now do it by running the following cli command

dotnet ef database update

Once the above command runs successfully, we see that the database, tables and the columns are created accordingly

If you do not see SQL server object explorer panel in your Visual Studio, you can open it by using the following keyboard combination:

ctrl / s

At this point we only have the table but no records inside it. Next, we will see how to create data.