UUID and TIMEUUID
Synopsis
Use the UUID data type to specify columns for data of universally unique IDs. TIMEUUID is a universal unique identifier variant that includes time information.
| Data type | Description |
|---|---|
UUID |
UUID (all versions) |
TIMEUUID |
UUID (version 1) |
Syntax
type_specification ::= { UUID | TIMEUUID }
uuid_literal ::= 4hex_block 4hex_block '-' 4hex_block '-' 4hex_block '-' 4hex_block '-' 4hex_block 4hex_block 4hex_block
4hex_block ::= hex_digit hex_digit hex_digit hex_digit
Where
hex_digitis a hexadecimal digit ([0-9a-fA-F]).
Semantics
- Columns of type
UUIDorTIMEUUIDcan be part of thePRIMARY KEY. - Implicitly, values of type
UUIDandTIMEUUIDdata types are neither convertible nor comparable to other data types. TIMEUUIDs are version 1 UUIDs: they include the date and time of their generation and a spatially unique node identifier.- Comparison of
TIMEUUIDvalues first compares the time component and then (if time is equal) the node identifier.
Examples
ycqlsh:example> CREATE TABLE devices(id UUID PRIMARY KEY, ordered_id TIMEUUID);
ycqlsh:example> INSERT INTO devices (id, ordered_id)
VALUES (123e4567-e89b-12d3-a456-426655440000, 123e4567-e89b-12d3-a456-426655440000);
ycqlsh:example> INSERT INTO devices (id, ordered_id)
VALUES (123e4567-e89b-42d3-a456-426655440000, 123e4567-e89b-12d3-a456-426655440000);
ycqlsh:example> UPDATE devices SET ordered_id = 00000000-0000-1000-0000-000000000000
WHERE id = 123e4567-e89b-42d3-a456-426655440000;
ycqlsh:example> SELECT * FROM devices;
id | ordered_id
--------------------------------------+--------------------------------------
123e4567-e89b-12d3-a456-426655440000 | 123e4567-e89b-12d3-a456-426655440000
123e4567-e89b-42d3-a456-426655440000 | 00000000-0000-1000-0000-000000000000