Database Reference
In-Depth Information
Chapter1.Introducing Cassandra
If at first the idea is not absurd, then there is no hope for it.
—Albert Einstein
Welcome to Cassandra:TheDeinitiveGuide. The aim of this topic is to help developers and
database administrators understand this important new database, explore how it compares to the
relational database management systems we're used to, and help you put it to work in your own
environment.
What's Wrong with Relational Databases?
If I had asked people what they wanted, they would have said faster horses.
—Henry Ford
I ask you to consider a certain model for data, invented by a small team at a company with thou-
sands of employees. It is accessible over a TCP/IP interface and is available from a variety of
languages, including Java and web services. This model was difficult at first for all but the most
advanced computer scientists to understand, until broader adoption helped make the concepts
clearer. Using the database built around this model required learning new terms and thinking
about data storage in a different way. But as products sprang up around it, more businesses and
government agencies put it to use, in no small part because it was fast—capable of processing
thousands of operations a second. The revenue it generated was tremendous.
And then a new model came along.
The new model was threatening, chiefly for two reasons. First, the new model was very different
from the old model, which it pointedly controverted. It was threatening because it can be hard to
understand something different and new. Ensuing debates can help entrench people stubbornly
further in their views—views that might have been largely inherited from the climate in which
they learned their craft and the circumstances in which they work. Second, and perhaps more
importantly, as a barrier, the new model was threatening because businesses had made consid-
erable investments in the old model and were making lots of money with it. Changing course
seemed ridiculous, even impossible.
Of course I'm talking about the Information Management System (IMS) hierarchical database,
invented in 1966 at IBM.
IMS was built for use in the Saturn V moon rocket. Its architect was Vern Watts, who dedicated
his career to it. Many of us are familiar with IBM's database DB2. IBM's wildly popular DB2
database gets its name as the successor to DB1—the product built around the hierarchical data
