Migrasi & Pengelolaan Skema

Apa Itu Migrasi EF Core?

Memasang Alat EF Core

# Install globally
dotnet tool install --global dotnet-ef

# Verify
dotnet ef --version

# Required NuGet packages in your project:
# Microsoft.EntityFrameworkCore.Design
# Microsoft.EntityFrameworkCore.SqlServer (or Sqlite, etc.)

Membuat Migrasi Pertama Anda

# Create initial migration
dotnet ef migrations add InitialCreate

# Output files created:
# Migrations/20240101_InitialCreate.cs       <- Up/Down
# Migrations/20240101_InitialCreate.Designer.cs
# Migrations/AppDbContextModelSnapshot.cs   <- current model

Isi Berkas Migrasi

public partial class InitialCreate : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.CreateTable(
            name: "Products",
            columns: table => new
            {
                Id    = table.Column<int>(nullable: false)
                             .Annotation("SqlServer:Identity", "1, 1"),
                Name  = table.Column<string>(maxLength: 200, nullable: false),
                Price = table.Column<decimal>(type: "decimal(18,2)", nullable: false)
            },
            constraints: table => table.PrimaryKey("PK_Products", x => x.Id));
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DropTable(name: "Products");
    }
}

Menerapkan Migrasi

# Apply all pending migrations
dotnet ef database update

# Apply up to a specific migration
dotnet ef database update AddProductIndex

# Roll back to a previous migration
dotnet ef database update InitialCreate

Migrasi Terprogram saat Aplikasi Dimulai

var app = builder.Build();

// Apply pending migrations at startup
using (var scope = app.Services.CreateScope())
{
    var db = scope.ServiceProvider.GetRequiredService<AppDbContext>();
    await db.Database.MigrateAsync();
}

app.Run();

Menambahkan Kolom dalam Migrasi Baru

// 1. Add property to entity
public class Product
{
    public int Id { get; set; }
    public string Name { get; set; } = "";
    public decimal Price { get; set; }
    public string? Description { get; set; } // NEW
}

// 2. Generate migration
// dotnet ef migrations add AddProductDescription

// Generated Up():
migrationBuilder.AddColumn<string>(
    name: "Description",
    table: "Products",
    nullable: true);

Pengisian Data dalam Migrasi

modelBuilder.Entity<Category>().HasData(
    new Category { Id = 1, Name = "Electronics" },
    new Category { Id = 2, Name = "Books" },
    new Category { Id = 3, Name = "Clothing" }
);

// Then regenerate the migration:
// dotnet ef migrations add SeedCategories

SQL Kustom dalam Migrasi

protected override void Up(MigrationBuilder migrationBuilder)
{
    migrationBuilder.Sql(@"
        CREATE VIEW vw_ActiveProducts AS
        SELECT Id, Name, Price
        FROM Products
        WHERE IsActive = 1
    ");
}

protected override void Down(MigrationBuilder migrationBuilder)
{
    migrationBuilder.Sql("DROP VIEW vw_ActiveProducts");
}

Menghapus Migrasi

# Remove the last unapplied migration
dotnet ef migrations remove

# List all migrations and their status
dotnet ef migrations list

# Script all migrations to SQL (for DBA review)
dotnet ef migrations script --output deploy.sql

Dunia Nyata: Strategi Migrasi CI/CD

# Generate idempotent script for all pending migrations
dotnet ef migrations script --idempotent --output migrations.sql

# Review migrations.sql, then apply via sqlcmd / psql:
# sqlcmd -S server -d db -i migrations.sql

Pemeriksaan Singkat

Ringkasan: Migrasi & Pengelolaan Skema