anchor.diff:  	LEFT_PAREN columnNameAndDefinition (COMMA columnNameAndDefinition)* RIGHT_PAREN
   	;
   
  +constraintDefinition:
  +	(CONSTRAINT symbol?)? (primaryKeyOption | uniqueOption | foreignKeyOption)
  +	;
  +	
   primaryKeyOption:	
   	PRIMARY KEY indexType? keyParts indexOption?
   	;
  
positive.code: }
  
  
  alterSpecifications:
  	alterSpecification (COMMA alterSpecification)*
  	;
  
negative.code: indexType:
      USING (BTREE | HASH)
  	;
  	
  indexOption:
      KEY_BLOCK_SIZE EQ_OR_ASSIGN? value
    | indexType
  