Cassandra query API-cqlsh

By default, Cassandra provides a prompt Cassandra query language shell (cqlsh) to facilitate user configuration debugging.

With cqlsh, you can do the following:

Define schemas, insert data, and execute queries. General command option usage introduction cqlsh-- help displays a help topic about options for the cqlsh command. Cqlsh-- version provides the version of cqlsh that you are using. Cqlsh-- color instructs shell to use color output. Cqlsh-- debug displays more debugging information. Cqlsh-- execute instructs shell to accept and execute the CQL command. Cql_statement instructs shell to accept and execute the CQL command. Cqlsh-- file= "file name" if you use this option, Cassandra will execute the command and exit in the given file. Cqlsh-- no-color instructs Cassandra not to use color output. Cqlsh-u "user name" uses this option to authenticate users. The default user name is cassandra. Cqlsh-p "pass word" uses this option, and you can authenticate the user with a password. The default password is cassandra. Start the cqlsh method:

Start cqlsh using the command cqlsh

Cqlsh 172.20.101.252-u cassandra-p cassandra default user, password: cassandra returns result: Connected to cn-engage-dev at 172.20.101.252 Connected to cn-engage-dev at 9042. [cqlsh 5.0.1 | Cassandra 3.11.4 | CQL spec 3.4.4 | Native protocol v4] Cqlsh command HELP-displays the help topics for all cqlsh commands. CAPTURE-captures the output of the command and adds it to the file. CONSISTENCY-displays the current conformance level or sets a new conformance level. COPY-copy data to Cassandra and copy data from Cassandra. DESCRIBE-describes the current cluster of Cassandra and its objects. EXPAND-output of the scale-up query. EXIT-use this command to terminate cqlsh. PAGING-enables or disables query paging. SHOW-displays details of the current cqlsh session, such as Cassandra version, host or data type assumptions. SOURCE-executes the file that contains the CQL statement. TRACING-enables or disables request tracking. The CQL data definition command CREATE KEYSPACE-creates a KeySpace in Cassandra. USE-Connect to the created KeySpace. ALTER KEYSPACE-change the properties of the KeySpace. DROP KEYSPACE-Delete the KeySpace. CREATE TABLE-create tables in KeySpace. ALTER TABLE-modifies the column properties of the table. DROP TABLE-deletes the table. TRUNCATE-removes all data from the table. CREATE INDEX-defines a new index on a single column of the table. DROP INDEX-deletes the named index. CQL data manipulation instruction INSERT-columns that add rows to the table. UPDATE-the column that updates the row. DELETE-removes data from the table. BATCH-execute more than one DML statement at a time. CQL sentence SELECT-this clause reads data from a table-the WHERE-where clause is used with select to read specific data. The ORDERBY-orderby clause is used with select to read specific data in a specific order.