Cassandra Practice Test

What is the structure of a primary key in Cassandra?

1. (clustering column, partition keys)

2. ((partition keys), clustering column)

3. (replication factor, clustering column)

4. ((clustering column), partition keys)

The correct answer is: ((partition keys), clustering column)

In Cassandra, the primary key is a crucial element that defines how data is organized and accessed within the database. The primary key comprises two parts: the partition key and the clustering columns. The partition key is used to determine the distribution of data across the cluster. It ensures that all rows with the same partition key are stored together on the same node, which allows for efficient data retrieval. On the other hand, clustering columns define the order in which the rows with the same partition key are sorted; they allow for more granular organization within each partition. The correct answer reflects this structure by emphasizing that the primary key is composed of the partition keys first, followed by the clustering columns. This hierarchical structure is essential for understanding how data is accessed and managed within Cassandra, allowing for efficient querying based on the partitioning and ordering of the data. In contrast, the other options do not accurately represent the relationship between partition keys and clustering columns or include invalid components like the replication factor, which does not play a role in defining the primary key structure.