To Use a GUID Field for an Existing Table

Add the ID field of type vachar2.
```
PK VARCHAR2(64));
```

Set the ID field to a GUID following XFM syntax.

UPDATE BUILDINGS SET PK = LOWER (substr(sys_guid(), 1, 8)||'-'||substr(sys_guid(),9,4)||'-'||substr(sys_guid(),13,4)||'-'||substr(sys_guid(),17,4)||'-'||substr(sys_guid(),21,12));

Set the primary key for the table.

ALTER TABLE BUILDINGS ADD CONSTRAINT BUILDINGS_PK PRIMARY KEY (PK);