实体框架重新创建相关实体

Question

1. I create new instance of some entity
2. I load a few another instances
3. I set them as reference in new instance
4. I save but EF create refernces instance one more time

Answer 1

You should read this article, Why Does Entity Framework Reinsert Existing Objects into My Database? , by Julie Lerman. She explains very well why this can occur and how you can avoid it.

Answer 2

If there is a relation in database between entities (tables), then upon saving parent object, all the child objects will also be saved if they are not null.

You are probably saving parent entity and then also saving child entities again.