Search code examples
databasegraph-databasesobject-oriented-database

Is there a database like this?

Background: Okay, so I'm looking for what I guess is an object database. However, the (admittedly few) object databases that I've looked at have been simple persistence layers, and not full-blown DBMSs. I don't know if what I'm looking for is even considered an object database, so really any help in pointing me in the right direction would be very appreciated.

I don't want to give you two pages describing what I'm looking for so I'll use an example to illustrate my point. Let's say I have a "BlogPost" object that I need to store. Something like this, in pseudocode:

class BlogPost
    title:String
    body:String
    author:User
    tags:List<String>
    comments:List<Comment>

(Assume Comment is its own class.)

Now, in a relational database, author would be stored as a foreign key pointing to a User.id, and the tags and comments would be stored as one-to-many or many-to-many relationships using a separate table to store the relationships. What I'd like is a database engine that does the following:

  • Stores related objects (author, tags, etc.) with a direct reference instead of using foreign keys, which require an additional lookup; in other words, objects on top of each other should be natively supported by the database
  • Allows me to add a comment or a tag to the blog post without retrieving the entire object, updating it, and then putting it back into the database (like a document-oriented database -- CouchDB being an example)

I guess what I'm looking for is a navigational database, but I don't know. Is there anything even remotely similar to what I'm thinking of? If so, what is it called? (Or better yet, give me an actual working database.) Or am I being too picky?

Edit:

Just to clarify, I am NOT looking for an ORM or an abstraction layer or anything like that. I am looking for an actual database that does this internally. Sorry if I'm being difficult, but I've searched and I couldn't find anything.

Edit:

Also, something for the JVM would be excellent, but at this point I really don't care what platform it runs on.

Solution

  • I think what you are describing could easily be modeled in a graph database. Then you get the benefit of navigating to the nodes/edges where you want to make changes without any need to retrieve anything else. For the JVM there's the Neo4j open source graph database (where I'm part of the team). You can read about it over at High Scalability, as part of an overview at thinkvitamin or in this stackoverflow thread. As for the tags, I think storing them in a graph database can give you some extra advantages if you want to find related tags and similar stuff. Just drop a line on the mailing list, and I'm sure the community will help you out.