How should I store a GUID in Oracle?
CREATE table test (testguid RAW(16) default SYS_GUID() )
This blog studied the relative performance.
As others have stated, there is a performance hit using GUIDs compared to numeric sequences. That said, there is a function named "SYS_GUID()" available since Oracle 8i that provides the raw equivalent:
SQL> SELECT SYS_GUID() FROM DUAL;
SYS_GUID()
--------------------------------
248AACE7F7DE424E8B9E1F31A9F101D5
A function could be created to return a formatted GUID:
CREATE OR REPLACE FUNCTION GET_FORMATTED_GUID RETURN VARCHAR2 IS guid VARCHAR2(38) ;
BEGIN
SELECT SYS_GUID() INTO guid FROM DUAL ;
guid :=
'{' || SUBSTR(guid, 1, 8) ||
'-' || SUBSTR(guid, 9, 4) ||
'-' || SUBSTR(guid, 13, 4) ||
'-' || SUBSTR(guid, 17, 4) ||
'-' || SUBSTR(guid, 21) || '}' ;
RETURN guid ;
END GET_FORMATTED_GUID ;
/
Thus returning an interchangeable string:
SQL> SELECT GET_FORMATTED_GUID() FROM DUAL ;
GET_FORMATTED_GUID()
--------------------------------------
{15417950-9197-4ADD-BD49-BA043F262180}
A note of caution should be made that some Oracle platforms return similar but still unique values of GUIDs as noted by Steven Feuerstein.
Update 11/3/2020: With 10g, Oracle added support for regular expression functions which means the concatenation can be simplified using the REGEXP_REPLACE()
function.
REGEXP_REPLACE(
SYS_GUID(),
'([0-9A-F]{8})([0-9A-F]{4})([0-9A-F]{4})([0-9A-F]{4})([0-9A-F]{12})',
'{\1-\2-\3-\4-\5}'
)
The expression breaks out the string value returned by SYS_GUID()
into 5 groups of hexadecimal values and rebuilds it, inserting a "-" between each group.