Understand the Value Propositions
Strategy No. 2: Understand the value propositions
The new database technologies of today were created to solve shortcomings in the relational database model. The three great goals of all systems are: availability (as the name implies, keeping the system available to users), scalability (ensuring that it meets the demands of all users or customers) and consistency (making sure that, when a data is changed, it is changed everywhere so that every user in the system sees the same thing at the same time).
The CAP theorem looks at this problem. To oversimplify, the CAP theorem says you can have any two but not all three. Traditional relational databases solved availability and consistency at the cost of scalability. The new, so-called NoSQL (Not Only SQL) databases primarily address availability and scalability to meet the needs of today's applications-with user and data loads far exceeding anything seen in the past.
Apache Hadoop, Cassandra, Amazon SimpleDB and Microsoft Windows Azure Table Services are some of the new databases designed to make things such as hundreds of thousands of users and petabytes of data problems of the past. There are many others as well. Some are specialized databases that solve very specific use cases such as analytical queries against huge data sets or extremely high-performance transactional systems. Then, you must also decide between cloud, on-premises or service models.
Before you get there, however, you first need to dig behind the technology hype and ask, "What business problem can these systems solve?" Only then you will know where to set your focus.