Oracle's SQL Assertions Reveal Why Legacy Join Syntax Still Matters

Oracle's SQL Assertions feature rejects ANSI JOIN syntax with an ORA-08697 error—a surprising limitation that stems from Oracle's internal constraint-checking mechanism using the SYS-owned DUAL table. This quirk illustrates how ANSI joins, introduced in Oracle 9i with internal transformations, continue to influence advanced database features. Developers and DBAs working with Oracle assertions must adapt their approach, as legacy join syntax remains a requirement despite SQL standards evolution.