To a person coming across from the relational database world to the NoSQL world, it would seem like a pretty featureless system. First, there is no relational integrity, then there is a whole different approach for defining a query before modeling your tables, which is quite the opposite of what we learned, that is, to model entities and then think of queries.
It may be confusing if you keep thinking in terms of a relational setup and translating it to an equivalent Cassandra representation. So forget about tables, foreign keys, joins, cascade delete, update on insert, and the like, when we speak in the context of Cassandra. If it helps, think of a problem you are dealing with. For example, you need to show number of votes by day and by city. We cannot run a sort or a group by; instead, we will have a column family, which will have counter as the data type and date as column names (at this point, if you start to think like an RDBMS person, you'll think how would you...