实体框架代码优先:插入数据库的NULL值
我正在使用实体框架代码优先方法。我有以下代码将数据插入到PaymentComponent和Payment表中。插入到PaymentComponent表中的数据不正确。即使域对象中的相应属性不为空,它也会在两列(对于一条记录)中具有NULL值。需要改变什么才能使其工作?实体框架代码优先:插入数据库的NULL值
编辑
当我添加了以下的NerdDinners类,我得到下面的结果 - 它有新的不需要的列
public DbSet<ClubCardPayment> ClubCardPayments { get; set; }
原码
static void Main(string[] args)
{
string connectionstring = "Data Source=.;Initial Catalog=NerdDinners;Integrated Security=True;Connect Timeout=30";
using (var db = new NerdDinners(connectionstring))
{
GiftCouponPayment giftCouponPayment = new GiftCouponPayment();
giftCouponPayment.MyValue=250;
giftCouponPayment.MyType = "GiftCouponPayment";
ClubCardPayment clubCardPayment = new ClubCardPayment();
clubCardPayment.MyValue = 5000;
clubCardPayment.MyType = "ClubCardPayment";
List<PaymentComponent> comps = new List<PaymentComponent>();
comps.Add(giftCouponPayment);
comps.Add(clubCardPayment);
var payment = new Payment { PaymentComponents = comps, PayedTime=DateTime.Now };
db.Payments.Add(payment);
int recordsAffected = db.SaveChanges();
}
}
域码
public abstract class PaymentComponent
{
public int PaymentComponentID { get; set; }
public abstract int MyValue { get; set; }
public abstract string MyType { get; set; }
public abstract int GetEffectiveValue();
}
public partial class GiftCouponPayment : PaymentComponent
{
private int couponValue;
private string myType;
public override int MyValue
{
get
{
return this.couponValue;
}
set
{
this.couponValue = value;
}
}
public override string MyType
{
get
{
return this.myType;
}
set
{
this.myType = value;
}
}
public override int GetEffectiveValue()
{
if (this.PaymentComponentID < 2000)
{
return 0;
}
return this.couponValue;
}
}
public partial class ClubCardPayment : PaymentComponent
{
private int cardValue;
private string myType;
public override int MyValue
{
get
{
return this.cardValue;
}
set
{
this.cardValue = value;
}
}
public override string MyType
{
get
{
return this.myType;
}
set
{
this.myType = value;
}
}
public override int GetEffectiveValue()
{
return this.cardValue;
}
}
public partial class Payment
{
public int PaymentID { get; set; }
public List<PaymentComponent> PaymentComponents { get; set; }
public DateTime PayedTime { get; set; }
}
//System.Data.Entity.DbContext is from EntityFramework.dll
public class NerdDinners : System.Data.Entity.DbContext
{
public NerdDinners(string connString): base(connString)
{
}
protected override void OnModelCreating(DbModelBuilder modelbuilder)
{
modelbuilder.Conventions.Remove<PluralizingTableNameConvention>();
}
public DbSet<GiftCouponPayment> GiftCouponPayments { get; set; }
public DbSet<Payment> Payments { get; set; }
}
REFERENCE:
- When using entity framework code-first mapping property to separate table, moves foreign key field
- Override Entity Framework Entity Property
- EntityFramework how to Override properties
- http://weblogs.asp.net/manavi/archive/2011/04/24/associations-in-ef-4-1-code-first-part-4-table-splitting.aspx
- http://www.robbagby.com/entity-framework/entity-framework-modeling-entity-splitting/
- 实体框架映射方案 - http://msdn.microsoft.com/en-us/library/cc716779.aspx
- http://blogs.microsoft.co.il/blogs/gilf/archive/2009/03/06/entity-splitting-in-entity-framework.aspx
直接在基类中实现MyType
和MyValue
。 EF允许共享成员仅在基类中实现。派生类中实现的成员在结果表中使用自己的列。
还没有定义的的DataContext ClubCardPayment dbset。
插入此,它应该工作
public DbSet<ClubCardPayment> ClubCardPayments { get; set; }
我已经更新了这个问题。即使这样,我也会得到意想不到的结果。请参阅最新的问题。 – Lijo 2012-07-24 08:39:10
您需要定义2类,实际上是实现了抽象类中,这是唯一的办法EF会知道不同类别,以及如何读取/更新/编写它们的实例。
(无需映射EF中的抽象类!)。
我有两个类实现抽象基类 - GiftCouponPayment和ClubCardPayment。 – Lijo 2012-07-24 08:41:06
这不会对您的问题有所贡献,而只是来自我身边的提示:
为什么在您的派生类中实现MyValue和MyType?你可以把它放到抽象类中,如果执行总是一样的话......
实施可能会在未来发生变化。我只是为了简单起见。 – Lijo 2012-07-24 08:43:18
谢谢。这是否意味着在EF中不支持重写属性? – Lijo 2012-07-24 08:44:09