We inherited Cassandra as part of the legacy system. 

Cassandra is an amazing piece of tech, but it has to be applied to the right problem domain, like all NoSQL data-stores.

For domain like blogs, social media and the like it's a great fit. Domains where it's valid to trade off consistency for scalability i.e CAP over ACID

It's quite a bad fit for our domain however. A good old RDBMS is much more suited. We've really struggled with Eventual Consistency and lack of Transactions.

Our app doesn't not need that kind of scalability and we need better ACID. hehe.

Knowing your problem domain and what you try to solve very well Deano! Good explanation. Thanks mate.

Yeah. Making the decision on what kind of data store to use is where the principle of The Last Responsible Moment really kicks in. 

Build as much of your app as possible while faking out persistence. Once you have a decent enough collection of running Use Cases in your system, then decide on the database. You'll be much better equipped to make a much a better decision.

I worked on project where we delayed the decision to choose a persistence technology for so long, we actually ended up going live saving data to the file system. No database was actually required in the end. I can't tell you how much time and money that saved.

http://goo.gl/Hxtxt

Very very insightful. It turns on another light in my mind ...