anchor.diff:      ;
   
   update: 
  -    updateClause 
  -    setClause 
  -    whereClause? 
  -    orderByClause? 
  -    limitClause?
  +    updateClause setClause whereClause? orderByClause? limitClause?
       ;
   
   setClause 
  
positive.code:     ;
  
  delete: 
      deleteClause 
      whereClause? 
      orderByClause? 
      limitClause?
      ;
  
  partitionClause 
  
negative.code: import Keyword, MySQLBase, DQLBase, BaseRule, DataType, Symbol;
  
  execute
      : select | insert | update | delete
      ;
  
  fromClause 
  