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node-red

How to extract data from a ned-red flow

I have 4 flows serial flow for my Arduino JSON flow to format my data in JSON format function flow to extract the data from my dht11 sensor and finally debug flow first i will show you the configuration of my flows my flows

my function : json flow

my sql database

sql database

the error message

error

my JSON flow

json flow

the output

data

help me please I thought that I will have had something like this in my database

"INSERT INTO sensordata (temperature,humidite) VALUES(20, 30);";

but i have

mysql> select *from sensordata ;
+--------+-----------+-------------+---------------------+
| idData | humidite  | temperature | dateSensor          |
+--------+-----------+-------------+---------------------+
|   2471 | undefined | undefined   | 2021-01-01 16:24:23 |
|   2472 | undefined | undefined   | 2021-01-01 16:24:24 |
+--------+-----------+-------------+---------------------+
Solution

  • Without knowing exactly what the input to the function node is I will have to guess.

    It looks like you are trying to access fields which don't exist on the msg object but can probably be found a level deeper in the msg.payload object.

    You can change the function node to:

    msg.topic = "insert into sensordata(temperature,humidite) values('" + msg.payload.temperature + "','" + msg.payload.humidite + "')"

    There is no need to attach the values to the msg object as extra payload#.