anchor.diff:  
   outOfLineConstraint
       : (CONSTRAINT ignoredIdentifier_)?
  -    (
  -    	UNIQUE columnNames
  -        | primaryKey columnNames 
  -        | FOREIGN KEY columnNames referencesClause
  -        | CHECK LP_ expr RP_
  -    ) 
  -    constraintState*
  +    (UNIQUE columnNames
  +    | primaryKey columnNames 
  +    | FOREIGN KEY columnNames referencesClause
  +    | CHECK LP_ expr RP_
  +    ) constraintState*
       ;
   
   outOfLineRefConstraint
  
positive.code: constraintState
      : notDeferrable 
      | initiallyClause 
      | RELY 
      | NORELY 
      | usingIndexClause 
      | ENABLE 
      | DISABLE 
      | VALIDATE 
      | NOVALIDATE 
      | exceptionsClause
      ;
  
  
negative.code:     ;
  
  exceptionsClause
      : EXCEPTIONS INTO tableName
      ;
  
  usingIndexClause
  