anchor.diff:  indexType:
       USING (BTREE | HASH)
   	;
  +	
   indexOption:
       KEY_BLOCK_SIZE EQ_OR_ASSIGN? value
     | indexType
  
positive.code: 	| REMOVE PARTITIONING
  	| UPGRADE PARTITIONING
  	;
  	
  singleColumn:
  	columnNameAndDefinition (FIRST | AFTER columnName)?
  
negative.code: 	LEFT_PAREN columnNameAndDefinition (COMMA columnNameAndDefinition)* RIGHT_PAREN
  	;
  
  constraintDefinition:
  	(CONSTRAINT symbol?)? (primaryKeyOption | uniqueOption | foreignKeyOption)
  	;
  	
  primaryKeyOption:	
  	PRIMARY KEY indexType? keyParts indexOption?
  	;
  