Lerning Entity Framework 6 ------ Complex types


Complex types are classes that map to a subset of columns of a table.They don't contains key. They are the Value Objects. For example, you have a entity named Company:

public class Company
{
    public int CompanyId { get; set; }

    public string CompanyName { get; set; }

    public string Street { get; set; }

    public string City { get; set; }

    public string Zip { get; set; }
}

You can Mondify it like this:

public class Company
{
    public Company()
    {
        this.Address = new Address();
    }
    public int CompanyId { get; set; }

    public string CompanyName { get; set; }

    public Address Address { get; set; }
}

public class Address
{
    public string Street { get; set; }

    public string City { get; set; }

    public string Zip { get; set; }
}

This structure can made the entity's meaning clearer than before. and the class Address can be used as a common value object for many classes. Now we complete all codes:

public class Company
{
    public Company()
    {
        this.Address = new Address();
    }
    public int CompanyId { get; set; }

    [MaxLength(100)]
    public string CompanyName { get; set; }

    public Address Address { get; set; }
}

public class Person
{
    public Person()
    {
        this.Address = new Address();
    }
    public int PersonId { get; set; }

    [MaxLength(50)]
    public string PersonName { get; set; }

    public Address Address { get; set; }
}

public class Address
{
    [MaxLength(100)]
    public string Street { get; set; }

    [MaxLength(50)]
    public string City { get; set; }

    [MaxLength(10)]
    public string Zip { get; set; }
}

public class MyContext:DbContext
{
    public MyContext() : base("name=Test")
    {

    }

    public DbSet<Company> Companies { get; set; }

    public DbSet<Person> People { get; set; }
}

Then, execute following commands in NuGet command line:

  • Enable-Migrations
  • Add-Migration Init
  • Update-Database

Now, The table people and companies'structures like this:

图片.png-8.6kB

图片.png-8.9kB

Let's have a test:

static void Main(string[] args)
{
    Address address = new Address
    {
        City = "BeiJing",
        Street = "ChangAn Street",
        Zip = "119"
    };

    Company company = new Company
    {
        CompanyName = "TianAnMen",
        Address = address
    };

    Person person = new Person
    {
        PersonName = "伟人",
        Address = address
    };

    using (MyContext db = new MyContext())
    {
        db.Companies.Add(company);
        db.People.Add(person);

        db.SaveChanges();
    }
}

You can provide the configuration for complex types. We can do so by providing a configuration class . The only difference is that we use a different base class, ComplexTypeConfiguration, not EntityTypeConfiguration.

That's all.

posted @ 2017-05-16 09:05 会长 阅读(...) 评论(...) 编辑 收藏