Issue Details (XML | Word | Printable)

Key: NUCMONGODB-24
Type: New Feature New Feature
Status: Open Open
Priority: Major Major
Assignee: Unassigned
Reporter: Andy Jefferson
Votes: 0
Watchers: 1
Operations

If you were logged in you would be able to see more operations.
DataNucleus Store MongoDB

Support MongoDB map/reduce capabilities through JDO/JPA query interface

Created: 14/Feb/11 11:51 AM   Updated: 22/Mar/12 08:00 PM
Component/s: None
Affects Version/s: None
Fix Version/s: None


 Description  « Hide
The MongoDB java driver has mapReduce() methods taking in the reduction definition. We need to take in the reduction definition, perhaps as query extension/hint(s).

Sort Order: Ascending order - Click to sort in descending order
Chris Rued added a comment - 22/Mar/12 07:46 PM
Do you have a use case in mind? Some scenario to give a better idea of how a user might make use of this capability?

Andy Jefferson added a comment - 22/Mar/12 08:00 PM
User has own conversion function for data perhaps, so used as bulk update type thing.

On a general note, with GAE v1 it stored data in a particular mode (with FK type info in elements). In v2 it is now stored in a new mode (with child information in property in the parent. To move from v1 to v2 a migration process would be a particular map function. Again, like a bulk update.

Obviously people more familiar (than me) with map-reduce will likely have their own uses; things that can't be expressed using JDOQL/JPQL maybe