我有3个表,
1),客户(编号,名称,BLA BLA) 2)CustomerGroups(GroupId的,组名) 3)CustomerInGroups(客户ID,的GroupId)
1) Customer (Id, Name, bla bla) 2) CustomerGroups (GroupId, GroupName) 3) CustomerInGroups (CustomerId, GroupId)
using (var context = DataObjectFactory.CreateContext())
{
context.Customers.Add(entity);
context.SaveChanges();
return entity.Id;
}
我如何添加一条记录CustomerInGroups?的EntityFramework不会产生这样的许多一对多映射表实体
How do I add a record into CustomerInGroups? EntityFramework doesn't generate entities for such many-to-many mapping tables
编辑:
无论是在客户和CustomerGroups的Id列设置为自动递增。
Both the Id columns in Customer and CustomerGroups are set to auto increment.
所以在我CustomersGroup表,我有
So in my CustomersGroup table, I have
Id Name
----------------------------
1 Normal
2 VIP
我想这样做,作为海报的一个建议:
I tried doing this as one of the posters suggested:
entity.CustomerGroups = new List<CustomerGroup>
{
new CustomerGroup {Id = 2 }
};
context.Customers.Add(entity);
context.SaveChanges();
return entity.Id;
然而,当我这样做,而不是创建一个记录在映射表是这样的:
However, when I did this, instead of creating a record in the mapping table like this:
CustomerId GroupId
----------------------------
1 2
我得到的是
CustomerInGroups
CustomerId GroupId
----------------------------
1 3
CustomerGroups
Id Name
----------------------------
1 Normal
2 VIP
3 NULL
它实际上创造了我CustomerGroups表中的另一个入口,这是不是我想要的。
It actually created another entry in my CustomerGroups table, which is not what I want
推荐答案
飞有点盲目的因为你没有包含什么样的属性实体
有。但是,你应该有一个关系的属性 CustomerGroups
。只需设置你要进行相关的团体属性。例如,这将创建一个新的组名称为foo栏和相关的实体组。
Flying a little blind since you didn't include what properties entity
has. But you should have a property for the relationship to CustomerGroups
. Just set that property with the groups you want to be related to. For example, this would create a new Group name "foo bar" and relate the entity to that group.
using (var context = DataObjectFactory.CreateContext())
{
entity.CustomerGroups = new List<CustomerGroup> { GroupName = "Foo bar" };
context.Customers.Add(entity);
context.SaveChanges();
return entity.Id;
}
如果关系是正确设置,EF会自动记录插入 CustomerGroups
并插入一个关系到 CustomerInGroups
表。
If the relationship is setup correctly, EF will automatically insert a record into CustomerGroups
and insert a relationship into the CustomerInGroups
table.
编辑:
如果你想添加现有 CustomerGroup
来新的客户。你想获得 CustomerGroup
从数据库中第一,然后将其添加到您所插入的Customer实体。
If you're trying to add an existing CustomerGroup
to a new Customer. You'll want to get the CustomerGroup
from the database first, then add it to the Customer entity you're inserting.
using (var context = DataObjectFactory.CreateContext())
{
var customerGroups = context.CustomerGroups.Where(...).ToList(); // get your CustomerGroup object(s) here, and ensure it's enumerated with ToList()
entity.CustomerGroups = customerGroups;
context.Customers.Add(entity);
context.SaveChanges();
return entity.Id;
}
相关推荐
最新文章