playOrm now supports N-level joins on cassandra (no limitations on where clause)

["Hiller, Dean" <De...@nrel.gov>]

There is no = or < limitations.  Joins are in beta and currently can only do inner joins at this time….Also, queries return a Cursor so you can page as well and keep the cursor in a web server session if needed for paging.

It also looks like joins may be faster with cassandra/playOrm vs. DBMS/hibernate.  We plan on running tests there to see.

The only limitation is you need to be able to partition your data into partitions and queries on these partitions are very fast.

Example SQL query ran in our JoinTest

@NoSqlQuery(name="findJoinOnPartition", query="PARTITIONS p(:partitionId) select p FROM TABLE as p INNER JOIN p.security as s where s.valuation > :value and p.numShares < :numShares)

The ad-hoc query tool supports the same syntax and is built off the same library, BUT the ad-hoc tool requires one of two things

 1.  You use the ORM so it writes meta data into cassandra OR
 2.  You write in meta data yourself into cassandra using the meta data apis in playOrm

Later,
Dean