text: var dbc = require('./config');
  
  module.exports = {
      query: function (sql,callback) {
          dbc.getConnection(function(err, connection) {
              connection.query(sql, function(err, result) {
                  if(err) {
                      callback(err);
                      // callback('error');
                  }else{
                      callback(result);
                  }
                  // 释放连接
                  connection.release();
              });
          });
      }
  }