Database Reference
In-Depth Information
FigureA-2.The need to manage data on a very large scale is increasing, and will continue to do so
It is at this point where the Web starts to employ that important second layer of semantics, ac-
companied by the explosion in volume of data, and where the largest web properties are forced
to start looking at alternatives to the relational database. Some semantic web researchers and
enthusiasts have recently suggested that we are entering a new era, Web 3.0, where RDF, micro-
formats, and ontologies will support a super-connected “web of data” culminating in a gigantic
graph of the world's knowledge base some years from now. As such, the usefulness of graph
databases, which directly support the idea of a semantic relationship between two nodes, be-
comes more immediately apparent.
Like many document-oriented databases, graph databases typically allow for free-form schemas,
allowing your application to evolve easily as your data set grows and changes. Because there is
no relational model, joins are not necessary, which can offer more efficient queries as your data
set grows.
The primary advantage of a graph database over RDBMS is that there's no impedance mismatch;
you can store your objects just as you would use them in your application and just as you would
draw them on a whiteboard, which makes for straightforward, readily understandable, and quick
modeling. As with key-value stores and document-oriented databases, graph databases allow you
to represent semistructured data and naturally evolve your schemas according to newfound rela-
tionships and properties.
If you're interested in exploring graph databases for a social web or Semantic Web application,
you might want to check out the variety of other graph databases not explored here, including
Dex, HypergraphDB, Infogrid, and VertexDB. I encourage you also to take a look at the Gremlin
project at
http://wiki.github.com/tinkerpop/gremlin
.
Gremlin is an open source programming
language designed specifically for performing queries, graph analysis, and manipulation in graph
