Question
Let's assume that we have such classes
public class A{
string someField { get; set; }
public virtual B B {get; set; }
}
public class B {
int someIntField {get; set; }
[ForeignKey("Id")]
[Required]
public virtual A A { get; set; }
}
In code I create new instances for both of them and making relation like:
A a = new A () { someField = "abcd"};
B b = new B () { someIntField = 42 };
A.B = b;
B.A = a;
Should I using DBContext to save both classes like that:
using (var db = new myDbContext()) {
myDbContext.As.Add(A);
myDbContext.Bs.Add(B);
myDBContext.SaveChanges();
}
Or saving it like that:
using (var db = new myDbContext()) {
myDbContext.As.Add(A);
myDbContext.SaveChanges();
}
is enough to store related objects into database?
Accepted Answer
From your example, if you instantiate new entity objects and then assign the child to the parent object's property, then EF will actually create a new child instance (record) and map it to the parent as a reference.
Your code snippet is a bit confusing because you've got reference from A to B and B to A but consider the following:
if you had 2 entities:
public class A
{
public int Id;
}
public class B
{
public int Id;
public A A;
}
and when saving you did something like this:
A a = new A();
B b = new B();
b.A = a;
dbcontext.SaveChanges();
then EF will create a new record for A, a new record for B and add the reference of newly created A record to B.
See this post for further details
Popular Answer
Saving the object that contains the other object is enough. It will automatically persist the changes to contained objects as well.
You could just create a small example and see for yourself what works.
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