This week, I attended a meeting about NoSQL. And so here is a summary of the notes i have taken and what i have learnt and understood, so far.
First, what is NoSQL ?
That term stands for (N)ot (O)nly SQL. A detailed definition can be found on Wikipedia.
Second, there are different models of NoSQL databases.
Apparently, Google (BigTable, ~2006) and Amazon (SimpleDB, S3, Dynamo, ~2007) were among the first ones to implement them.
The different store models are :
There was much talk about the ACID rules, scalability, elasticity, consistency …
Also a formula was introduced : R+W>N
* N – Number of replicas (nodes) for any data item
* W – Number or nodes a write operation blocks on
* R – Number of nodes a read operation blocks on
I still have to study what that formula means !
The event sourcing pattern was quickly introduced.
A few links :
There exists a NoSQL user group in Paris :
Graph Databases, NOSQL and Neo4j