在GAE中<->“ CompositKey”查找的双向键？

Question

Am writing a Go application on GAE And I have a type called Connection{Token, ToAdress, FromAdress}

I want to store it in the datastore so that I can look it up via GetConnectionByT(Token string) But also via GetConnectionByA(FromAdress,ToAdress string)

What is the best way of doing this? Right now my Connect type have two different .key() functions and I insert duplicate entry's with different keys every time I add but this feels really really wrong :)

Is datastore.NewQuery("Connection").Filter the way to go? Seames that a key should be faster and cheaper? But if not how do I filter multiple fields?

Answer 1

If you check the documentation for datastore.Query.Filter you'll note that multiple filters are ANDed together. So you can do this kind of thing:

q := datastore.NewQuery("Connection").
    Filter("FromAddress =", a1).
    Filter("ToAddress =", a2).
    Order("-FromAddress")

If you have a key for the entity in question then yes, using the key will probably be faster. However it's a bit difficult to tell from the description in your question.