EF核心实体平等

Question

Sorry if this is a dumb question, most of my experience with ORMs has not been EF, and looking this up online gets me a lot of bad hits. It's almost like "reference" means different things to different people...

If I write code like so:

using (var db = new DbContext())
{
    var entity1 = await db.Foos.FirstOrDefaultAsync(x => x.Id == 1);
    var entity2 = await db.Foos.FirstOrDefaultAsync(x => x.Id == 1);
    return entity1.Equals(entity2);
}

This returns true . Since my entity is a reference type, the Equals under the hood should be an Object.ReferenceEquals() call.

What I want to know is, is this reliable, ie will any entity represented by a particular database record in a context always be referentially equal, or can it "drop out" of the cache, get reloaded on demand and have a new reference like what happens in some less sophisticated ORMs? If an entity is loaded as part of a collection on another entity, is it still the same object? Are there rules/ settings that govern this behavior?

Answer 1

正如@IvanStoev在评论中指出的那样，引用一致性是设计和EF的核心部分，因此数据库中的同一对象应始终引用数据库上下文中的相同对象...至少在特定的范围内您正在使用的数据库上下文。如果您正在处理多个数据库上下文，则为YMMV。