[Developers] MQL /type/link changes

[Tyler Pirtle]

My dear [Developers],

Quite a few of you have noticed there's a particular unpleasantness 
dealing with
/type/link in divulging the histories of Freebase (Iain, Kurt, I'm 
looking at you).

As of today this has been fixed! Kurt's original problems with querying 
deleted
inks has been resolved as well as several other known and unknown problems
surrounding /type/link. We haven't removed any existing functionality -
we've only fixed the broken cases. I'm just letting you all know
that there's more you can do with /type/link now than you could've 
yesterday.

Along with these changes we've changed some of the semantics regarding the
'valid' property of /type/link. Below you'll find a short list of 
definitions
for two of the major properties in /type/link, 'operation' and 'valid'. 
If there's
any questions regarding the behavior of these properties feel free to ask.

Cheers,


Tyler
/user/teeler




New semantics of 'valid' and 'operation'
=========================================

"valid"

    * true -- return links that correspond to mql values that are
      currently in effect (not updated or deleted).
    * false -- return links that correspond to previously updated or
      deleted mql values.
    * null -- return all links (valid or invalid) along with the valid
      status (true or false).

This is different from the current mql behavior where "valid":null may 
sometimes be returned. With the new behavior, null is never returned.

"operation"

    * "insert" -- constrain the query to return links (object, property,
      value tuples) asserted for the first time
    * "update" -- constrain the query to return links asserted
      overriding a previous value (previous value becomes invalid)
    * "delete" -- constrain the query to return links that have been
      deleted, unasserting the previous value
    * null -- return operation status ("insert", "update", or "delete").