anchor.diff:  	;
   	
   other_key_specification[SchemaDef schema]
  -	: ( unique__key_specification[$schema]
  -	  | nonunique_key_specification[$schema]
  -	  ) 
  +	: nonunique_key_specification[$schema]
   	index_type[$schema]?
   	LEFT_PAREN index_key_column[$schema] (COMMA index_key_column[$schema])* RIGHT_PAREN
   	;
  
positive.code: 	: column_specification[$schema]
  	| key_constraint[$schema]? primary_key_specification[$schema] index_option[$schema]* { $schema.finishConstraint(SchemaDef.IndexQualifier.UNIQUE); }
  	| key_constraint[$schema]? foreign_key_specification[$schema] index_option[$schema]* { $schema.finishConstraint(SchemaDef.IndexQualifier.FOREIGN_KEY); }
  	| other_key_specification[$schema] index_option[$schema]*
  	;
  	
  
negative.code: 
  unique__key_specification[SchemaDef schema]
  	: UNIQUE (KEY | INDEX)? qname? {$schema.addIndex($qname.name);  $schema.addIndexQualifier(SchemaDef.IndexQualifier.UNIQUE);}
  		index_type[$schema]?
  	  LEFT_PAREN index_key_column[$schema] (COMMA index_key_column[$schema])* RIGHT_PAREN
  	;
  
  nonunique_key_specification[SchemaDef schema]
  