Is there a way to map complex types with EF Core

ComplexType mappings are now available since EF Core 2.0. There are currently two ways to do this that I am aware of.

Via Attributes

Not specifying the Column attribute may cause Entity Framework to not map properties to the correct column in existing tables without migrations.

e.g., it may map to Address_StreetAddress

using System.ComponentModel.DataAnnotations.Schema;

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

    // The complex property we want to use
    public Address Address { get; set; }

    public string UserName{ get; set; }
}

// Lets Entity Framework know this class is a complex type
[ComplexType]
public class Address
{
    // Maps the property to the correct column name
    [Column("Address")]
    public string StreeAddress { get; set; }

    [Column("City")]
    public string City { get; set; }

    [Column("State")]
    public string State { get; set; }

    [Column("Zip")]
    public string ZipCode { get; set; }
}

Via Fluent API

Not specifying the HasColumnName may cause Entity Framework to not map properties to the correct column in existing tables without migrations.

e.g., it may map to Address_StreetAddress

using Microsoft.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore.Metadata.Builders;

public class MyContext: DbContext
{
    public DbSet<User> Users{ get; set; }

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

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);

        builder.Entity<User>(table =>
        {
            // Similar to the table variable above, this allows us to get
            // an address variable that we can use to map the complex
            // type's properties
            table.OwnsOne(
                x => x.Address,
                address =>
                {
                    address.Property(x => x.City).HasColumnName("City");
                    address.Property(x => x.State).HasColumnName("State");
                    address.Property(x => x.StreetAddress).HasColumnName("Address");
                    address.Property(x => x.SuiteNumber).HasColumnName("SuiteNumber");
                    address.Property(x => x.ZipCode).HasColumnName("Zip");
                });
        });
    }
}