Cassandra comparator and validator

comparator - data type for a column key/name

validator - data type for a column value or row key

If the comparator and validator are not specified for a column family, the column keys and column values would be store as hex byte arrays (BytesType).

key_validation_class - data type for row key

default_validation_class - dynamic column families whose column names are not known ahead of time

The validators for each column value should be specified during column family creation via the column_metadata property.

Columns are stored in sorted order by their column names within a row. The data type for the column names are determined by the comparator. The comparator cannot be changed after creation.