title: Cannot update child record when Delete rule is NO ACTION
body: <p>In ORACLE database, I tried to update a record <code>ENTITY_ID</code> in a table <code>TICKETS</code>. I got the following error message:<br>
  <code>SQL Error: ORA-00001: unique constraint (TICKET_U01) violated
  00001. 00000 -  "unique constraint (%s.%s) violated"
  *Cause:    An UPDATE or INSERT statement attempted to insert a duplicate key.
             For Trusted Oracle configured in DBMS MAC mode, you may see
             this message if a duplicate entry exists at a different level.
  *Action:   Either remove the unique restriction or do not insert the key.</code>  </p>
  
  <p>However, when I checked I found the <code>DELETE RULE</code> in this table is <code>NO ACTION</code> among the constraints. The record <code>ENTITY_ID</code> is a FK referenced to the table <code>ENTITY</code>. My question is, is not <code>NO ACTION</code> rule applied to the parent record in this case, I mean I should get this error when I try to update the record from the table <code>ENTITY</code> rather than the table <code>TICKETS</code>. Am I missing something here ?</p>