mysql - 在函数 Node 中查询-red

Question

通过在 Node-Red 的功能 Node 中执行查询，如何在同一 Node 内引用查询的结果？
我们正在附加我们的 Node 。或者目标是创建一个自动图书馆，有这个问题，我们不能插入多个相同的书，具有不同的 ID。

我们的 Node

[{"id":"893d2899.cc8238","type":"function","z":"16cd4688.876b29","name":"CICLO FOR MAGAZZINO","func":"var prova = null;\nvar length = msg.payload.length;\nfor(var i=0; i< length; i++){\n var libroInAnalisi = msg.payload[i].idlibro;\n var magazzino = msg.magazzino;\n msg.topic = \"SELECT idlibro FROM magazzino WHERE idmagazzino = \" + msg.magazzino + \" AND idlibro = \" + msg.payload[i].idlibro;\n prova = msg.paylod; /*we can not processed this msg.payload in our for cycle again. This result is not processed from the for but is our enter value; we need that this value will be the result of our query */\n if (prova.length > 0 ) {\n
i = length;\n return msg;\n }\n}\nreturn msg;\n
\n\n","outputs":1,"noerr":0,"x":1960.3333740234375,"y":3691.333251953125,"wires":[[]]}]

Answer 1

我们的 Node
[{"id":"6c2611b5.7557c","type":"mqtt in","z":"16cd4688.876b29","name":"","topic":"InvioSedeTitolo","qos": "2","broker":"ef4521ef.a299c8","x":208.5001220703125,"y":3506.1668090820312,"wires":[["1a471c90.0a42db","2c52854d.e1abea"]]},{"id ":"2c52854d.e1abea","type":"json","z":"16cd4688.876b29","name":"","property":"payload","action":"","pretty ":false,"x":397.2620544433594,"y":3505.4763793945312,"wires":[["af4c5cbd.736df8"]]},{"id":"af4c5cbd.736df8","type":"change", "z":"16cd4688.876b29","name":"","rules":[{"t":"set","p":"magazzino","pt":"msg","to":"payload.0","tot":"msg"},{"t":"set","p":"titolo","pt":"msg","to":"payload.1","tot":"msg"},{"t":"set","p":"autore","pt":"msg","to":"payload.2","tot":"msg"},{"t":"set","p":"chatId","pt":"msg","to":"payload.3","tot":"msg"},{"t":"set","p":"data","pt":"msg","to":"payload.4","tot":"msg"}],"action":"", "属性":"","来自":"","to":"","re​​g":false,"x":606.5001220703125,"y":3504.1668090820312,"wires":[["2e07cb45.b7ccdc","9e50c718.365d58"]]},{"id":"9e50c718.36 5d58","type":"change","z":"16cd4688.876b29","name":"SELECTidLibro","rules":[{"t":"set","p":"topic","pt":"msg","to":"SELECT idlibro FROM Libri WHERE titolo = ?和自动 = ? ","tot":"str"},{"t":"set","p":"payload","pt":"msg","to":"[\tmsg.titolo,\tmsg. autore\t\t]","tot":"jsonata"}],"action":"","property":"","from":"","to":"","re​​g": false,"x":839.6668090820312,"y":3505.1670532226562,"wires":[["95314a01.d2eb58","ff75b9d0.a297c"]]},{"id":"95314a01.d2eb58","type": "mysql","z":"16cd4688.876b29","mydb":"ac96c738.c838b","name":"libri","x":1069.6671142578125,"y":3506.988067626953,"wires":[[ "50780f2e.e31f8","930fd299.160f08","95a2d410.fbe098","2a1ea1a8.88ba3e"]]},{"id":"2a1ea1a8.88ba3e","type":"function","z": "16cd4688.876b29","name":"EMPTY","func":"var empty;\nif (msg.payload.length > 0){\n empty=0;\n} else {\n empty = 1 ;\n}\nmsg.empty = empty;\nreturn msg;","outputs":1,"noerr":0,"x":1227.1668701171875,"y":3516.1668090820312,"wires":[["314d3f64. 3dcbd8"]]},{"id":"314d3f64.3dcbd8","type":"switch","z":"16cd4688.876b29","name":"","property":"empty", "propertyType":"msg","rules":[{"t":"eq","v":"0","vt":"num"},{"t":"eq","v ":"1","vt":"num"}],"checkall":"true","re​​pair":false,"输出":2,"x":1370.9447021484375,"y":3514.8334350585938,"wires":[["893d2899.cc8238"],[]]},{"id":"893d2899.cc8238", "type":"function","z":"16cd4688.876b29","name":"CICLO FOR MAGAZZINO","func":"var prova = null;\nvar length = msg.payload.length;\nfor (变量 i=0;我<长度； i++){\n var libroInAnalisi = msg.payload[i].idlibro;\n var magazzino = msg.magazzino;\n msg.topic =\"在 idmagazzino =\"+ msg.magazzino +\"的地方选择 idlibro AND idlibro =\"+ msg.payload[i].idlibro;\n prova = msg.paylod;/*我们不能在我们的for循环中再次处理这个msg.payload。这个结果不是从 for 处理的，而是我们的输入值；我们需要这个值是我们查询的结果 */\n if (prova.length > 0 ) {\ni = length;\n return msg;\n }\n}\nreturn msg;\n\n\n","输出":1,"noerr":0,"x":1598.6668701171875,"y":3506.6106567382812,"wires":[["de18a0fd.f963e"]]},{"id":"de18a0fd. f963e","type":"mysql","z":"16cd4688.876b29","mydb":"ac96c738.c838b","name":"magazzino","x":1841.613037109375,"y":3495.2676391601562 ,"wires":[["7baa967.2cb4468","d10e16d.0469e68"]]},{"id":"7baa967.2cb4468","type":"debug","z":"16cd4688.876b29","名称":"","事件":true,"tosidebar":true,"控制台":false,"tostatus":false,"完成":"有效负载","x":1925.7799682617188,"y": 3383.613235473633,"wires":[]},{"id":"ef4521ef.a299c8","type":"mqtt-broker","z":"","name":"","broker":"iot.eclipse.org","port":"1883","clientid":"","usetls":false,"compatmode":true,"keepalive":"60","cleansession":true,"willTopic ":"","willQos":"0","willPayload":"","birthTopic":"","birthQos":"0","birthPayload":""},{"id":"ac96c738 .c838b","type":"MySQL数据库","z":"","host":"127.0.0.1","port":"3306","db":"Biblioteca","tz":""}]