部署到linux服务器出现以下问题，貌似是连接不到数据库。返回500 Internal Server Error。求高手指点 {"error":{"message":"Cannotcallmethod’createConnection’ofundefined","stack":"TypeError:Cannotcallmethod’createConnection’ofundefined\natObject.mysqlOrm.init(/data/node/microblog/modules/db.js:31:29)\natexports.requesttrafficweibo(/data/node/microblog/controller/site.js:371:11)\natcallbacks(/data/node/microblog/node_modules/express/lib/router/index.js:161:37)\natparam(/data/node/microblog/node_modules/express/lib/router/index.js:135:11)\natpass(/data/node/microblog/node_modules/express/lib/router/index.js:142:5)\natRouter._dispatch(/data/node/microblog/node_modules/express/lib/router/index.js:170:5)\natObject.router(/data/node/microblog/node_modules/express/lib/router/index.js:33:10)\natnext(/data/node/microblog/node_modules/express/node_modules/connect/lib/proto.js:190:15)\natObject.cookieParserashandle\natnext(/data/node/microblog/node_modules/express/node_modules/connect/lib/proto.js:190:15)"}}