Morphia is an Apache-licensed Google Code project that lets you persist, retrieve, delete, and query POJOs stored as documents in MongoDB. Morphia accomplishes this by providing a set of annotations and a wrapper around the Mongo Java driver. Morphia is conceptually similar to object-relational mappers such as Java Persistence API (JPA) or Java Data Objects (JDO) implementations. In this article, I’ll show how to use Morphia with a Java domain model mapped to MongoDB.

There are various ways to use MongoDB from Java and major MongoDB Java frameworks got compared.

Original title and link: Domain-model persistence with Morphia and MongoDB (NoSQL databases © myNoSQL)

via: http://www.ibm.com/developerworks/java/library/j-morphia/index.html?ca=drs-

As protocols, APIs are an extremely important part of the product and in case you have a rich API you might face criticism:

Now if a DeadlockDetectedException, HaCommunicationException, NotFoundException(thrown if a request is made to a node, relationship or property that does not exist), NotInTransactionException, ReadOnlyIndexException or TransactionFailureException were thrown, what would I really do about it? Nothing much, unfortunately. There is no way I could be smart and recover from these. At the most I’d log it and re-throw it.

A while back I had my part of suggestions related to Neo4j API and some of those became part of the Neo4j 1.2 roadmap. Problem is not that API is not fixable, but if you want to maintain backward compatibility things are quickly becoming complicated (or leading to ugly APIs).

Update: I’ve received a couple of comments that made me realize that most probably I haven’t expressed myself too well. So here is another attempt:

1. it is normal for graph databases (and embedded databases) to have richer APIs. That’s why I’ve suggested to some of the graph databases to look more into providing it as a service, as that would reduce a bit the complexity
2. it is normal that a complex API would not always be obvious and perfect to everybody
3. it is great to get feedback about your API (in whatever form it comes, from “your API sucks” to “it’s good, but I’d like to be able to do this and that”) as it means that:
   • your users are getting deeper into your product and they care about it
   • you’ll have a chance to improve it over time so new users will find a better API
4. maintaining backward compatibility for complex APIs is always a challenge and you must think about this as early as possible so you can follow the same policy over time

Original title and link: Neo4j Exceptions (NoSQL databases © myNoSQL)

via: http://thought-bytes.blogspot.com/2010/12/runtimeexceptions-and-neo4j.html

There are five different APIs recommended by CouchDB for use with Java. Each one uses a different API for JSON encode/decode, for logging and for the HTTP Stuff. If you want to use SSL, that’s also implemented differently

If they don’t want to support official libraries for CouchDB for every language, maybe they’ll do it for the ones where people are really confused on how to get started. Just maintaining a list as I do on NoSQL libraries for CouchDB is not enough.

Original title and link: CouchDB and Java (NoSQL databases © myNoSQL)

via: http://www.raditha.com/blog/archives/3003.html

In case you cannot use Redis with Grails, you might find JOhm interesting:

JOhm is a Java library for storing objects in Redis, a persistent key-value database.

Still in early versions, but looks promising.

Original title and link: JOhm: Object-Hash Mapping for Redis and Java (NoSQL databases © myNoSQL)

via: http://github.com/xetorthio/johm

It would be nice if there were an R package, along the lines of RMySQL, for MongoDB. For now there is not — so, how best to get data from a MongoDB database into R

I told you before about R and “data addicts”

Original title and link: MongoDB and R using Java (NoSQL databases © myNoSQL)

via: http://nsaunders.wordpress.com/2010/09/24/connecting-to-a-mongodb-database-from-r-using-java/

In the days the news are about instant searches and auto complete, Salvatore Sanfilippo (@antirez) shows how to use Redis sorted sets and corresponding commands (ZRANGE, ZRANK) to implement autocompletion:

The initial code in Ruby:

already got ported to Python:

and ☞ Java and ☞ PHP.

As Ilya Grigorik (@igrigorik) commented, this is building a ☞ Trie with Redis.

Original title and link: Redis: Implementing Auto Complete or How to build Trie on Redis (NoSQL databases © myNoSQL)

via: http://antirez.com/post/autocomplete-with-redis.html