How to create a table corresponding to enum in EF Core Code First?

Question

How would one turn the enums used in an EF Core database context into lookup tables and add the relevant foreign keys?

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• Same as EF5 Code First Enums and Lookup Tables but for EF Core instead of EF 6
• Related to How can I make EF Core database first use Enums?

Answer 1

You can use an enum in your code and have a lookup table in your db by using a combination of these two EF Core features:

• Value Conversions - to convert the enum to int when reading/writing to db
• Data Seeding - to add the enum values in the db, in a migration

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Here below a data model example:

public class Wine {     public int WineId { get; set; }     public string Name { get; set; }      public WineVariantId WineVariantId { get; set; }     public WineVariant WineVariant { get; set; } }  public enum WineVariantId : int {     Red = 0,     White = 1,     Rose = 2 }  public class WineVariant {     public WineVariantId WineVariantId { get; set; }     public string Name { get; set; }      public List<Wine> Wines { get; set; } } 

Here the DbContext where you configure value conversions and data seeding:

public class WineContext : DbContext {     public DbSet<Wine> Wines { get; set; }     public DbSet<WineVariant> WineVariants { get; set; }      protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)     {         optionsBuilder.UseSqlite("Data Source=wines.db");     }      protected override void OnModelCreating(ModelBuilder modelBuilder)     {         modelBuilder             .Entity<Wine>()             .Property(e => e.WineVariantId)             .HasConversion<int>();          modelBuilder             .Entity<WineVariant>()             .Property(e => e.WineVariantId)             .HasConversion<int>();          modelBuilder             .Entity<WineVariant>().HasData(                 Enum.GetValues(typeof(WineVariantId))                     .Cast<WineVariantId>()                     .Select(e => new WineVariant()                     {                         WineVariantId = e,                         Name = e.ToString()                     })             );     } } 

Then you can use the enum values in your code as follow:

db.Wines.Add(new Wine {     Name = "Gutturnio",     WineVariantId = WineVariantId.Red, });  db.Wines.Add(new Wine {     Name = "Ortrugo",     WineVariantId = WineVariantId.White, }); 

Here is what your db will contain:

I published the complete example as a gist: https://gist.github.com/paolofulgoni/825bef5cd6cd92c4f9bbf33f603af4ff