Final answer:
Each keyspace in a column-oriented database like Apache Cassandra can have one or more column families.
Step-by-step explanation:
In a column-oriented database like Apache Cassandra, the fundamental organizational unit is the keyspace, akin to a database in traditional relational systems. Within each keyspace, data is structured into one or more column families, where each family comprises rows with shared structural characteristics. The statement, "Each keyspace has at least one and often many column families," accurately captures the essence of Cassandra's data model. This design philosophy allows for the flexible organization of diverse data types within a keyspace, as each column family can represent a distinct category of information with its own set of columns. The ability to have multiple column families within a keyspace facilitates efficient data management by optimizing storage and retrieval operations based on specific use cases or access patterns. Overall, this approach contributes to the scalability and adaptability of Apache Cassandra in handling a variety of data structures and access requirements within a distributed and highly available environment.