Using the Database - CQL Introduction¶

Getting Started Using CQLsh¶

CQLsh 2 is the default query language and CQLsh 3 is the new, recommended version. After starting the Cassandra Server, follow these steps to get started using CQLsh 3 quickly:

1. Start CQLsh 3 on Linux or Mac:

   From the bin directory of the Cassandra installation, run the cqlsh script.

   cd <install_location>/bin
   
   ./cqlsh --cql3
   

2. Create a keyspace to work with:

   cqlsh> CREATE KEYSPACE demodb
            WITH strategy_class = 'org.apache.cassandra.locator.SimpleStrategy'
            AND strategy_options:replication_factor='1';
   

   cqlsh> USE demodb;
   

3. Create a column family (the counterpart to a table in relational database world):

   cqlsh> CREATE TABLE users (
            user_name varchar,
            password varchar,
            state varchar,
            PRIMARY KEY (user_name)
          );
   

4. Enter and read data from Cassandra:

   cqlsh> INSERT INTO users
            (user_name, password)
            VALUES ('jsmith', 'ch@ngem3a');
   
   cqlsh> SELECT * FROM users WHERE user_name='jsmith';
   

   The output is:

    user_name | password  | state
   -----------+-----------+-------
       jsmith | ch@ngem3a |  null
   

5. Exit CQLsh:

   cqlsh> exit