“实体类型‘X’的实例映射到具有键值 Guid 的同一行，但具有不同的原始属性”异常是什么意思

Question

I have a complex model in ef core. There are a lots of inheritance and references. Sometimes I am getting an error on saving context:

The instance of entity type 'X' and the instance of entity type 'Y' are mapped to the same row with the >key value '{Guid: 29421520-1733-4659-b38b-f1b8bdafb0c1}', but have different original property values

What does this error mean? Is the problem is in the model, or in business logic, mapping... and how to resolve it?

Answer 1

You never got an answer eh? I'm assuming you found an answer by now, but I just ran into this problem today, and since I resolved it, figured I'd share my answer.

Cause : two separate entities that were both mapped to the same column in the database and were both being saved during the same transaction but with different values.

In my case, I had a DateTime column Xyz in a ProgressTracking [ComplexType] child-object, and apparently someone couldn't find the property in the ComplexType object so they added the same fields to the parent object...so reading works fine and most saves work fine...until you update one of the values but not the other...then when you save...CRASH, If you wanted it to work: I'm assuming you would have to do:

var newValue = DateTime.Now;
obj.Xyz = newValue;
obj.ProgressTracking.Xyz = newValue;

Which, I'm not going to try the above to see if it works because that would be asinine. So:

Solution : remove the property from the parent object and leave it on the ComplexType, then refactor any usages...there were none:-/... I really hope I'm not the one who did that (afraid to check source control:-P )