anchor.diff:  That would return messages starting with latest.
   
   
  -Currently only targeted collection column fields can be specified for sorting. The following would work:
  +Currently only targeted collection column fields can be specified for sorting. The following wouldn't work:
   
       ?sort=user.nick
   
  
positive.code:       "rooms" : [ ]
      }
  
  In this case we assume there are two additional tables present in our database with foreign key constraint referencing the 'users' table. The ids of those tables are used to name a 'synthetic' collection fields 'messages', and 'rooms'. This is how many-to-one relationships are automatically resolved.
  
  Since this item was only just created it can't possibly have any references pointing to it yet, therefore these two fields are empty.
  
  
negative.code: 
  When creating related items using nesting the foreign key columns connecting master-child tables will be filled automatically, so in this case there is no need to specify in message instance a back link to the wrapping user instance via 'user' field on the message.
  
  Also notice how in 'room' within a message we only specify a 'self' / 'href' field. This is called a _resource reference_. Table 'messages' has a many-to-one relationship with 'rooms', which means that 'messages' table contains a foreign key column 'room_id' that links to table 'rooms'.
  
  Currently creating nested instances related via many-to-one relationship is not supported. Support for this may be added in the future.
  
  == Updating records (items)
  
  