Cassandra Query Language (CQL)
|cqlsh --help||Shows help topics about the options of cqlsh commands.|
|cqlsh --version||Provides the version of the cqlsh you are using.|
|cqlsh --color||Directs the shell to use colored output.|
|cqlsh --debug||Shows additional debugging information.|
|cqlsh --execute cql_statement||Directs the shell to accept and execute a CQL command.|
|cqlsh --file= “file name”||If you use this option, Cassandra executes the command in the given file and exits.|
|cqlsh --no-color||Directs Cassandra not to use colored output.|
|cqlsh -u “user name”||Using this option, you can authenticate a user. The default user name is: cassandra.|
|cqlsh -p “pass word”||Using this option, you can authenticate a user with a password. The default password is: cassandra.|
Documented Shell Commands¶
Given below are the Cqlsh documented shell commands. These are the commands used to perform tasks such as displaying help topics, exit from cqlsh, describe,etc.
HELP− Displays help topics for all cqlsh commands.
CAPTURE− Captures the output of a command and adds it to a file.
CONSISTENCY− Shows the current consistency level, or sets a new consistency level.
COPY− Copies data to and from Cassandra.
DESCRIBE− Describes the current cluster of Cassandra and its objects.
EXPAND− Expands the output of a query vertically.
EXIT− Using this command, you can terminate cqlsh.
PAGING− Enables or disables query paging.
SHOW− Displays the details of current cqlsh session such as Cassandra version, host, or data type assumptions.
SOURCE− Executes a file that contains CQL statements.
TRACING− Enables or disables request tracing.
CQL Data Definition Commands¶
CREATE KEYSPACE− Creates a KeySpace in Cassandra.
USE− Connects to a created KeySpace.
ALTER KEYSPACE− Changes the properties of a KeySpace.
DROP KEYSPACE− Removes a KeySpace
CREATE TABLE− Creates a table in a KeySpace.
ALTER TABLE− Modifies the column properties of a table.
DROP TABLE− Removes a table.
TRUNCATE− Removes all the data from a table.
CREATE INDEX− Defines a new index on a single column of a table.
DROP INDEX− Deletes a named index.
CQL Data Manipulation Commands¶
INSERT− Adds columns for a row in a table.
UPDATE− Updates a column of a row.
DELETE− Deletes data from a table.
BATCH− Executes multiple DML statements at once.
SELECT− This clause reads data from a table
WHERE− The where clause is used along with select to read a specific data.
ORDERBY− The orderby clause is used along with select to read a specific data in a specific order.