Use NoSql? And if yes how?

Question

I read and heared a lot (podcasts, stackoverflow questions..) about NoSQL-Databases and I am really curious to use them, but...

Although I read a lot of things like how-to-sql-or-nosql or what-scalability-problems-have-you-solved-using-a-nosql-data-store I am still not certain which kind of DB to use.

The Problem is: For a (school) project we (my project group) need to implement a quite big database (that should serve a rest-server, probably written in erlang, with lots of clients). We are quite good at designing datamodels for relational databases. So we startet to do that.

Now I played around with some NoSQL and was really impressed by the performance. So: Is it a good Idea to use a NoSQL Database? Our Datamodel has lots of relations and the queries would have lots of joins (or at least use joined views). I sometimes read this means I should go with a relational Database and in other places I read this means I could easily redesign it into NoSQL-Style to loose this overhead of relations.

Should I use NoSQL and if yes, which of the systems would you suggest me to use? Are Things like HanderlerSocket for MySQL are an option? And how can I easily redesign a relational Datamodel into NoSQL-Style?

Answer 1

The answer to your question is: It totally depends on your data and requirements. In a real-world project you would analyze the benefits of various NoSQL-Databases (HBase, Cassandra, MongoDB, CouchDB, Riak,...) in your special project. Then you could evaluate these against the benefits of a classical RDBMS like MySQL.

In a school project like yours a NoSQL-Database is mainly a decision of taste as your project will probably never benefit from typical NoSQL-advantages like schemalessness or sharding.

A redesign of a relational datamodel can be a very tricky task as you have to wrap up your mind around the different database model of the chosen NoSQL-database. Joins are not necessarily a problem if your business data fits the database model of your chosen NoSQL-database. Sometimes Join-intensive relational models are a lot easier to implement in some NoSQL-Databases (e.g. a Document oriented database like MongoDB).

If you really want to try out NoSQL go with MongoDB as it is very well documented for a first entry.

As a german-speaker (Grützi in die Schweiz aus Berlin) I recommend you to read the following book in German, which helps you to get the main reasons for using a NoSQL-database and explains the main steps to start using the most popular NoSQL-Databases: NoSQL: Einstieg in die Welt nichtrelationaler Web 2.0 Datenbanken

Answer 2

Please keep in mind that you are not required to use just 1 data storage engine. You can use SQL and noSQL solutions in parallel.

Just remember to document your database/noSQL structures properly.

-daniel