A resource that doesn't relate to anything else is probably a sign of a missing definition.

Relationships can be explicit or implicit. Explicit relationships are defined by the client—they create Post 123, and they tell the server that Post 123 relates to Category 456.

Implicit relationships are calculated based on other inputs. The client tells you a Billing Address's postal code is 11217, and the related Order gets related to Shipping Options accordingly.

Avoid optional relationships.

TK Move some of what's in the Resource chapter into this chapter

Included/Expanded Resources

TK

Updating to-many resources

TK