MongoDB : Unity JDBC
JDBC Driver for MongoDB®
The JDBC driver for MongoDB runs SQL queries against MongoDB for any Java application that supports JDBC. SQL support includes functions, expressions, aggregation, and joins including for collections with nested objects and arrays. See the features and SQL examples supported by the JDBC driver for MongoDB. The JDBC driver also supports the TokuMX MongoDB distribution.
Features
- Access data in MongoDB collections via SQL including WHERE filters and ORDER BY.
- Manipulate and control data using standard SQL functions not natively supported by MongoDB.
- Perform SQL joins across MongoDB collections and databases.
- Full support for nested documents (subdocuments) and arrays including filters and expressions.
How it works
- The SQL query is validated and translated into a MongoDB query and executed using the MongoDB Java library.
- The generated MongoDB query can be output in text form which provides a SQL to MongoDB translation tool and service.
- Metadata is exposed to relational systems through JDBC by building a representative schema by sampling the datastore and fitting the least-general type that will represent the data.
- SQL features not natively supported by MongoDB and the JDBC driver are executed using the UnityJDBC virtualization engine.
Source & more details at : http://www.unityjdbc.com/mongojdbc/mongo_jdbc.php