Custom JPA implementation // existing No SQL JPA implementations

Question

Background:

I've been using JPA lately, and I am very impressed by how easily I was able to produce a persistence layer for a reasonably large relational database project.

We use a lot of no-sql databases at my company, specifically column oriented ones. I have some questions about potentially using JPA for those databases:

Questions

1. Can JPA be used with NO-SQL databases? It stands to reason that if the framework can generate a query for a SQL database and map the results, then it probably could reasonably easily be tailored to generate a different kind of query and a different mapping, for say, querying Hadoop maybe?

2. If it's possible, are there any existing implementaitons of JPA that use things besides SQL?

3. Are there any good resources on implementing/extending JPA? I realize TSQL, PLSQL, etc. must all be specifically addressed in JPA, so there must be an extensibility mechanism we can manipulate.

Answer 1

As per your question i came across Hibernate OGM which stands for Hibernate Object Grid Mapper which provides JPA (java Persistence api)the support for the NoSQL solutions. Hibernate OGM has the following capabilities : -

1. persists entities into a NoSQL
2. datastore specific native queries
3. full-text queries, using Hibernate Search as indexing engine

I haven't explore more on this framework OGM but looks very promising solution for your questions. You can refer to the following URL to get more idea about the Hibernate OGM

• http://hibernate.org/ogm/

Answer 2

There are various JPA implementations that support (the badly termed) "NoSQL" set of datastores. The most complete we've found to be DataNucleus which also provides the more suitable JDO API also. It supports MongoDB, Cassandra, HBase, AppEngine, LDAP, spreadsheets, Neo4j, and some others