In the preceding chapters, you learned how to use Cassandra as a primary data store for the MyStatus application, with a focus on modeling the data that drives the main user experience on the site. In this chapter, we'll shift focus to another popular use of Cassandra: aggregating data that we observe over time. In particular, we'll build a small analytics component into our schema, which will allow us to keep track of how many times a given status update was viewed on a given day.
In order to do this, we'll introduce a new type of column, the counter column, which is a special numeric column type that can be discretely incremented or decremented. Counter columns have a lot in common with collection columns, which we explored in the previous chapter: you can make discrete changes to them without reading their current value, and they're good for scenarios in which...
