c# - 如何在 EF 代码优先中映射继承的实体

Question

我正在尝试将 AdventureWorks 2012 示例数据库映射到 EF 6.1.3 代码优先数据层，但我对如何映射 Employee 感到困惑和 Person实体。 Employee 显然应该来自 Person , 与 Person.PersonType的 EM , 但我不知道如何使用 EntityTypeConfiguration<TEntity> 来映射它“映射”类。知道这一点，我也可以映射 Person从 BusinessEntity 派生.

Answer 1

我将解释如何使用 Code First 方法在 Employee 和 Person 表之间执行映射，您可以按照相同的过程在 之间映射继承BusinessEntity 和 Person。

使用的继承映射策略是 TPT(每个类型的表)，我创建了一个简单的控制台应用程序，安装了 AdventureWorks2012 数据库后，我按照 EF DataModel 向导生成代码第一类，我将修改这些类以映射继承，所以这里是结果代码:

Person 类:

public  partial class Person
{
    [Key]
    public int BusinessEntityID { get; set; }

    [Required]
    public string PersonType { get; set; }

    public bool NameStyle { get; set; }

    public string Title { get; set; }

    [Required]
    public string FirstName { get; set; }

    public string MiddleName { get; set; }

    [Required]
    public string LastName { get; set; }

    public string Suffix { get; set; }

    public int EmailPromotion { get; set; }

    [Column(TypeName = "xml")]
    public string AdditionalContactInfo { get; set; }

    [Column(TypeName = "xml")]
    public string Demographics { get; set; }

}

员工类:

 public partial class Employee: Person
{

    [Required]
    public string NationalIDNumber { get; set; }

    [Required]
    public string LoginID { get; set; }

    [DatabaseGenerated(DatabaseGeneratedOption.Computed)]
    public short? OrganizationLevel { get; set; }

    [Required]
    public string JobTitle { get; set; }

    [Column(TypeName = "date")]
    public DateTime BirthDate { get; set; }

    [Required]
    public string MaritalStatus { get; set; }

    [Required]
    public string Gender { get; set; }

    [Column(TypeName = "date")]
    public DateTime HireDate { get; set; }

    public bool SalariedFlag { get; set; }

    public short VacationHours { get; set; }

    public short SickLeaveHours { get; set; }

    public bool CurrentFlag { get; set; }

    public Guid rowguid { get; set; }

    public DateTime ModifiedDate { get; set; }
}

最后是 AW 上下文类:

 public partial class AW : DbContext
{
    public AW()
        : base("name=AWConnectionString")
    {
    }

    public virtual DbSet<Employee> Employees { get; set; }

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


    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {            
        modelBuilder.Entity<Person>().ToTable("Person.Person");
        modelBuilder.Entity<Employee>().ToTable("HumanResources.Employee");
    }
}

一个简单的测试(对我有用 ;)):

 class Program
{
    static void Main(string[] args)
    {
        using(var db= new AW())
        {
            var e = db.Employees.First();
            e.JobTitle = "Web Developper";
            db.SaveChanges();
        }
    }
}

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