Oracle Build UUID

Select Sys_guid () from dual;

-->78ae331adb2b4ce7ab598b1317b39d58

But the function has the following problem:
1 . The return type is raw
2 . No- (dash) delimiter
3 . Capitalization of letters returned

To make the resulting UUID conform to the RFC 4122 standard
Create the function as follows and test pass.

Create or Replace function Get_uuid return VARCHAR2 is
V_uuid varchar (36);
Begin
V_uuid: = Lower (Rawtohex (Sys_guid ()));
V_uuid: = substr (V_uuid, 1, 8) | | '-' | | SUBSTR (V_uuid, 9, 4) | | '-' | |
SUBSTR (V_uuid, 13, 4) | | '-' | | SUBSTR (V_uuid, 17, 4) | | '-' | |
SUBSTR (V_uuid, 21, 12);
return v_uuid;
End Get_uuid;

Select Get_uuid () from dual;
-->7bb0152a-4c5c-4078-a1b8-f57ae58254e5

Oracle Build UUID