How data modeling should be approached for Apache Cassandra. A music service example is used throughout the CQL document.

The music service example shows the how to use compound keys, clustering columns, and collections to model Cassandra data.

An index provides a means to access data in Apache Cassandra™ using attributes other than the partition key for fast, efficient lookup of data matching a given condition.

Indexes provide operational ease for populating and maintaining the index.

Internally, CQL does not change the row and column mapping from the Thrift API mapping. CQL and Thrift use the same storage engine.

How to start cqlsh.

You can use tab completion to see hints about how to complete a cqlsh command.

Creating a keyspace is the CQL counterpart to creating an SQL database.

Steps for creating a table with a single primary key.

An example of creating a user-defined type to attach multiple data fields to a column.

Details about Apache Cassandra database objects and cluster configuration in the system keyspace tables.

Using the SELECT command.

The IN keyword can define a set of clustering columns to fetch together, supporting a "multi-get" of CQL rows.

Slicing over rows of a partition when the table has more than one clustering column and comparing groups of clustering keys to certain values.

An example of batching conditional updates combined with static columns.

When to use batches.

To simplify tracking multiple keyspaces, use the keyspace qualifier instead of the USE statement.

Adding columns to a table with the ALTER TABLE command.

Data in a column, other than a counter column, can have an optional expiration period called TTL (time to live).

Using the DROP and DELETE commands.

Using the WRITETIME function in a SELECT statement to determine when the date/time that the column was written to the database.

Changing the data type of a column after it is defined or added to a table using ALTER TABLE.

Collection types provide an improved way of handling tasks, such as building multiple email address capability into tables.

Using cqlsh to create an index on column values.

INSERT and UPDATE statements that use the IF clause support lightweight transactions, also known as Compare and Set (CAS).

Using CQL to page through rows.

A counter is a special column for storing a number that is changed in increments.

This tutorial shows the difference between these consistency levels and the number of replicas that participate to satisfy a request.

About using CQL.

CQL input consists of statements that change data, look up data, store data, or change the way data is stored.

Built-in data types for columns.

About using CQL keyspace and table properties.

CQL support functions for transforming one or more column values into a new value.

Upper CQL limits.

The cqlsh commands.

CQL commands.