UUID Data Type - MariaDB Knowledge Base

Description

The UUID data type is intended for the storage of 128-bit UUID (Universally Unique Identifier) data. See the UUID function page for more details on UUIDs themselves.

Retrieval

Data retrieved by this data type is in the string representation defined in RFC4122 .

Casting

String literals of hexadecimal characters and CHAR / VARCHAR / TEXT can be cast to the UUID data type. Likewise hexadecimal literals , binary-literals , and BINARY / VARBINARY / BLOB types can also be cast to UUID.

The data type will not accept a short UUID generated with the UUID_SHORT function, but will accept a value without the - character generated by the SYS_GUID function (or inserted directly). Hyphens can be partially omitted as well, or included after any group of two digits.

The type does not accept UUIDs in braces, permitted by some implementations.

Storage

UUID are stored in an index friendly manner, the order of a UUID of llllllll-mmmm-Vhhh-vsss-nnnnnnnnnnnn is stored as:

nnnnnnnnnnnn-vsss-Vhhh-mmmm-llllllll

This provides a sorting order, assuming a UUIDv1 (node and timestamp) is used, of the node, followed by the timestamp. The key aspect is the timestamps are sequential.

MariaDB starting with 10.10

Starting from MariaDB 10.10.6 and MariaDB 10.11.5 , taking into account that UUIDv7 and other versions are designed around time ordering, UUIDs version >= 6 are now stored without byte-swapping, and UUIDs with version >=8 and variant=0 are now considered invalid (as the standard expects)

Examples

CREATE TABLE t1 (id UUID);

Directly Inserting via string literals :

INSERT INTO t1 VALUES('123e4567-e89b-12d3-a456-426655440000');

Directly Inserting via hexadecimal literals :

INSERT INTO t1 VALUES (x'fffffffffffffffffffffffffffffffe');

Generating and inserting via the UUID function .

INSERT INTO t1 VALUES (UUID());

Retrieval:

SELECT * FROM t1;
+--------------------------------------+
| id                                   |
+--------------------------------------+
| 123e4567-e89b-12d3-a456-426655440000 |
| ffffffff-ffff-ffff-ffff-fffffffffffe |
| 93aac041-1a14-11ec-ab4e-f859713e4be4 |
+--------------------------------------+

The UUID_SHORT function does not generate valid full-length UUID:

INSERT INTO t1 VALUES (UUID_SHORT());
ERROR 1292 (22007): Incorrect uuid value: '99440417627439104' 
  for column `test`.`t1`.`id` at row 1

Accepting a value without the - character, either directly or generated by the SYS_GUID function:

INSERT INTO t1 VALUES (SYS_GUID());
SELECT * FROM t1;
+--------------------------------------+
| id                                   |
+--------------------------------------+
| 123e4567-e89b-12d3-a456-426655440000 |
| ffffffff-ffff-ffff-ffff-fffffffffffe |
| 93aac041-1a14-11ec-ab4e-f859713e4be4 |
| ea0368d3-1a14-11ec-ab4e-f859713e4be4 |
+--------------------------------------+
SELECT SYS_GUID();
+----------------------------------+
| SYS_GUID()                       |
+----------------------------------+
| ff5b6bcc1a1411ecab4ef859713e4be4 |
+----------------------------------+
INSERT INTO t1 VALUES ('ff5b6bcc1a1411ecab4ef859713e4be4');
SELECT * FROM t1;
+--------------------------------------+
| id                                   |
+--------------------------------------+
| 123e4567-e89b-12d3-a456-426655440000 |
| ffffffff-ffff-ffff-ffff-fffffffffffe |
| 93aac041-1a14-11ec-ab4e-f859713e4be4 |
| ea0368d3-1a14-11ec-ab4e-f859713e4be4 |
| ff5b6bcc-1a14-11ec-ab4e-f859713e4be4 |
+--------------------------------------+

Valid and invalid hyphen and brace usage: