CQL data types

Built-in data types for columns.

CQL defines built-in data types for columns. The counter type is unique.

Table 1. CQL Data Types
CQL Type	Constants supported	Description
ascii	strings	US-ASCII character string
bigint	integers	64-bit signed long
blob	blobs	Arbitrary bytes (no validation), expressed as hexadecimal
boolean	booleans	true or false
counter	integers	Distributed counter value (64-bit long)
date	strings	Value is a date with no corresponding time value; Cassandra encodes date as a 32-bit integer representing days since epoch (January 1, 1970). Dates can be represented in queries and inserts as a string, such as 2015-05-03 (yyyy-mm-dd)
decimal	integers, floats	Variable-precision decimal Java type Note: When dealing with currency, it is a best practice to have a currency class that serializes to and from an int or use the Decimal form.
double	integers, floats	64-bit IEEE-754 floating point Java type
float	integers, floats	32-bit IEEE-754 floating point Java type
frozen	user-defined types, collections, tuples	A frozen value serializes multiple components into a single value. Non-frozen types allow updates to individual fields. Cassandra treats the value of a frozen type as a blob. The entire value must be overwritten. Note: Cassandra no longer requires the use of frozen for tuples: `frozen <tuple <int, tuple<text, double>>>`
inet	strings	IP address string in IPv4 or IPv6 format, used by the python-cql driver and CQL native protocols
int	integers	32-bit signed integer
list	n/a	A collection of one or more ordered elements: [literal, literal, literal]. CAUTION: Lists have limitations and specific performance considerations. Use a frozen list to decrease impact. In general, use a set instead of list.
map	n/a	A JSON-style array of literals: { literal : literal, literal : literal ... }
set	n/a	A collection of one or more elements: { literal, literal, literal }
smallint	integers	2 byte integer
text	strings	UTF-8 encoded string
time	strings	Value is encoded as a 64-bit signed integer representing the number of nanoseconds since midnight. Values can be represented as strings, such as 13:30:54.234.
timestamp	integers, strings	Date and time with millisecond precision, encoded as 8 bytes since epoch. Can be represented as a string, such as 2015-05-03 13:30:54.234.
timeuuid	uuids	Version 1 UUID only
tinyint	integers	1 byte integer
tuple	n/a	Cassandra 2.1 and later. A group of 2-3 fields.
uuid	uuids	A UUID in standard UUID format
varchar	strings	UTF-8 encoded string
varint	integers	Arbitrary-precision integer Java type

In addition to the CQL types listed in this table, you can use a string containing the name of a JAVA class (a sub-class of AbstractType loadable by Cassandra) as a CQL type. The class name should either be fully qualified or relative to the org.apache.cassandra.db.marshal package.

Enclose ASCII text, timestamp, and inet values in single quotation marks. Enclose names of a keyspace, table, or column in double quotation marks.

Java types

The Java types, from which most CQL types are derived, are obvious to Java programmers. The derivation of the following types, however, might not be obvious:

Table 2. Derivation of selective CQL types
CQL type	Java type
decimal	java.math.BigDecimal
float	java.lang.Float
double	java.lang.Double
varint	java.math.BigInteger

CQL type compatibility

CQL data types have strict requirements for conversion compatibility. The following table shows the allowed alterations for data types:


Data type may be altered to:	Data type
ascii, bigint, boolean, decimal, double, float, inet, int, timestamp, timeuuid, uuid, varchar, varint	blob
int	varint
text	varchar
timeuuid	uuid
varchar	text

Clustering columns have even stricter requirements, because clustering columns mandate the order in which data is written to disk. The following table shows the allow alterations for data types used in clustering columns:


Data type may be altered to:	Data type
int	varint
text	varchar
varchar	text