RAW(16) vs. CHAR(32): Choosing the Right Way to Store GUIDs in Oracle

• This is the recommended approach for storing raw binary data like GUIDs.
• A RAW(16) column can hold exactly 16 bytes, the same size as a standard GUID.
• Example:

CREATE TABLE my_table (
  id RAW(16) PRIMARY KEY,
  data VARCHAR2(255)
);

-- Generate and insert a GUID
DECLARE
  guid RAW(16);
BEGIN
  guid := SYS_GUID();
  INSERT INTO my_table (id, data) VALUES (guid, 'This is some data');
END;
/

Using CHAR(32):

• This stores the GUID as a hexadecimal string with 32 characters (due to two characters per byte).
• While it works, it's less efficient compared to RAW(16) for storage and comparisons.

CREATE TABLE my_table (
  id CHAR(32) PRIMARY KEY,
  data VARCHAR2(255)
);

-- Generate and insert a GUID (needs conversion)
DECLARE
  guid_string VARCHAR2(32);
BEGIN
  guid_string := DBMS_OUTPUT.PUT_LINE(SYS_GUID());
  INSERT INTO my_table (id, data) VALUES (guid_string, 'This is some data');
END;
/

Related Issues and Solutions:

• Performance: Using RAW(16) generally offers better performance compared to CHAR(32) for storing and comparing GUIDs.
• Portability: If your application needs to work across different databases, using RAW(16) provides a more consistent approach.

Additional Considerations:

• Generating GUIDs: You can use the SYS_GUID() function to generate unique identifiers within your database.
• Primary Key: Both RAW(16) and CHAR(32) columns can be used as primary keys to ensure uniqueness within your table.