Cassandra TTL & Cassandra CQL Data Types (Example)

Cassandra Data Types

Cassandra supports different types of data types. Here is the table that shows data types, their constants, and description.

CQL Type	Constants	Description
ascii	Strings	US-Ascii character string
Bigint	Integers	64-bit signed long
Blob	Blobs	Arbitrary bytes in hexadecimal
Boolean	Booleans	True or false
Counter	Integers	Distributed counter values 64 bit
Decimal	Integers, floats	Variable precision decimal
Double	Integers, floats	64-bit floating point
Float	Integers, floats	32-bit floating point
Frozen	Tuples, collections, user defined types	Stores cassandra types
Inet	Strings	IP address in IPV4 or IPV6 format
Int	Integers	32 bit signed integer
List		Collection of elements
Map		Json style collection of elements
Set		Collection of elements
Text	Strings	UTF-8 encoded strings
Timestamp	Integers, strings	Id generated with date plus time
Timeuuid	Uuids	Type 1 uuid
Tuple		A group of 2,3 fields
Uuid	Uuids	Standard uuid
Varchar	Strings	UTF-8 encoded string
Varint	Integers	Arbitrary precision integer

Cassandra TTL (Time to Live) using Automatic Data Expiration

Cassandra provides functionality by which data can be automatically expired.

During data insertion, you have to specify ‘ttl’ value in seconds. ‘ttl’ value is the time to live value for the data. After that particular amount of time, data will be automatically removed.

For example, specify ttl value 100 seconds during insertion. Data will be automatically deleted after 100 seconds. When data is expired, that expired data is marked with a tombstone.

A tombstone exists for a grace period. After data is expired, data is automatically removed after compaction process.

Syntax

Insert into KeyspaceName.TableName(ColumnNames) values(ColumnValues)
	using ttl TimeInseconds;

Example

Here is the snapshot where data is being inserted in Student table with ttl value of 100 seconds.

insert into University.Student(rollno,name,dept,semester) values(3,'Guru99','CS’,7) using ttl 100;

Here is the snapshot where data is automatically expired after 100 seconds and data is automatically removed.

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