实体框架4.1代码优先外键ID [英] Entity Framework 4.1 Code First Foreign Key Id's
问题描述
我有两个实体被一对多引用.当实体框架创建表时,它将创建两个外键,一个用于我通过fluent接口指定的键,另一个用于ICollection.如何摆脱重复的外键?
I have two entities referenced one to many. When entity framework created the table it creates two foreign keys, one for the key I have specified with the fluent interface and the other for the ICollection. How do I get rid of the duplicate foreign key?
public class Person
{
public long RecordId { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public string Email { get; set; }
public string Username { get; set; }
public long DepartmentId { get; set; }
public virtual Department Department { get; set; }
}
public class Department
{
public long RecordId { get; set; }
public string Name { get; set; }
public virtual ICollection<Person> People { get; set; }
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Person>()
.HasRequired(p => p.Department)
.WithMany()
.HasForeignKey(p => p.DepartmentId)
.WillCascadeOnDelete(false);
}
谢谢!
推荐答案
您必须明确指定关联的多端:
You must specify the many-end of the association explicitely:
modelBuilder.Entity<Person>()
.HasRequired(p => p.Department)
.WithMany(d => d.People)
.HasForeignKey(p => p.DepartmentId)
.WillCascadeOnDelete(false);
否则,EF将假定存在两种关联:不会在Department
中用外键DepartmentId
和Person
类中的外键DepartmentId
和导航属性Department
公开,就像您在Fluent代码中定义的那样-另一个关联属于公开的导航属性People
,但另一个关联的未公开端位于Person
中,并且由EF自动创建外键.那是您在数据库中看到的另一个键.
Otherwise EF will assume that there are two associations: One which is not exposed in Department
with the foreign key DepartmentId
and navigation property Department
in the Person
class as you have defined in the Fluent code - and another association which belongs to the exposed navigation property People
but with another not exposed end in Person
and a foreign key automatically created by EF. That's the other key you see in the database.
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