What is the method for setting primary keys in Cassandra?

The way to set up a primary key in Cassandra is by defining the components of the primary key in the table creation statement. The primary key consists of one or more columns and can be divided into partition key and clustering key.

Partition keys are used to distribute data across different nodes, their values determine the distribution of data in the cluster. When creating a table, one or more columns need to be specified as partition keys, and multiple columns can be grouped together using parentheses.

The sort key is used to sort data within a partition. Its value determines the storage order of data within each partition. When creating a table, the sort key column can be added to the primary key to specify how data is sorted within the partition.

The method for setting the primary key is as follows:

1. Create a primary key with a single column.
2. Create a table named table_name with a primary key column of data_type, and the primary key constraint on the primary_key_column.
3. Create a primary key with multiple columns.
4. The following code creates a table named table_name with two partition key columns, two clustering columns, and a primary key consisting of the partition key columns and clustering columns.

When creating a table, you can choose the columns for partition key and sort key as needed, as well as their order. These choices will be determined based on the data’s read and write patterns and query requirements.