WiredPrairie is right. You can definitely write a tool to export Oracle data directly to Mongo, but this is unreasonable.
Your Oracle data is most likely normalized, and Mongo is dealing with denormalized data.
I know that MongoVUE can import data from a relational database ( http://www.mongovue.com/ ), but again, direct import will be a headache.
Some steps to go from one to another:
- Create the objects / documents that you want to find in Mongo. Objects that will be closely related to your application objects. For example, an object / document Animals. What fields do you need?
- Write queries in Oracle that produce fully implemented Animal. In Oracle, you can have tables called AnimalType, Animal, AnimalInfo, etc. You want to join them to create one large Animal object.
- Write a tool for pumping data from (2) - (1). For example, if you need three stored procedures or queries to create an Animal object, your code will run these procedures, create an object in any language, serialize this object in JSON, and then write in Mongo.