Entity Framework start flow

1. Create models

Models represent database tables

    class Dish
    {
        public int Id { get; set; }

        [MaxLength(100)]
        public string Title { get; set; } = string.Empty;

        [MaxLength(1000)]
        public string? Notes { get; set; }

        public int? Starts { get; set; }

        public List<DishIngredient> Ingredients { get; set; } = new();
    }

    class DishIngredient
    {
        public int Id { get; set; }

        public string Description { get; set; } = string.Empty;
    
        [MaxLength(50)]
        public string UnitOfMeasure { get; set; } = string.Empty;

        [Column(TypeName = "decimal(5, 2)")]
        public decimal Amount { get; set; }

        public Dish? Dish { get; set; }

        public int DishId { get; set; }
    }

2. Create a db context

Represents connection string with db

    class CookbookContext : DbContext
    {
        public DbSet<Dish> Dishes { get; set; } = null!;

        public DbSet<DishIngredient> Ingredients { get; set; } = null!;

        public CookbookContext(DbContextOptions<CookbookContext> options) : base(options)
        { }
    }

3. Create a db context factory

We can use appsettings.json for the purposes of storing connection data

    class CookbookContextFactory : IDesignTimeDbContextFactory<CookbookContext>
    {
        public CookbookContext CreateDbContext(string[]? args = null)
        {
            var configuration = new ConfigurationBuilder().AddJsonFile("appsettings.json").Build();

            var optionsBuilder = new DbContextOptionsBuilder<CookbookContext>();
            optionsBuilder
                .UseLoggerFactory(LoggerFactory.Create(builder => builder.AddConsole()))
                .UseSqlServer(configuration["ConnectionStrings:DefaultConnection"]!);

            return new CookbookContext(optionsBuilder.Options);
        }
    }

appsettings.json file

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=localhost;Database=CookbookLesson;User=sa;Password=***"
  }
}

4. Install ef globally on your machine

dotnet tool install --global dotnet-ef

5. Migrations

Migrations are needed to transfer data from C# to a database table. From solution directory run dotnet ef migrations add Initial to add initial migration that will be responsible for converting C# instances to db table records.

To finally create a db run dotnet ef database update

NuGet packages to be installed:

Microsoft.EntityFrameworkCore.SqlServer

Microsoft.Extensions.Configuration.Json

Microsoft.EntityFrameworkCore.Design

Microsoft.Extensions.Logging.Console

daverbk / entity-practice