How to pass a parameter to dashDB query using Node-RED editor? - ibm-cloud

Question

In Bluemix Node-RED application I use Cloudant and dashDB services. I replicated Cloudant database into dashDB which contains multiple values stored in a table like DALERT,DEVICE,ID etc.
I am trying to search records from the CLOUDANT table in my dashDB using DALERT column which value is equal to critical.
I am trying these way in Node-RED editor but unable to retrieve data from dashDB:
[
{"id":"9941f62b.66be08","type":"http in","name":"","url":"/get/specificcritical","method":"get","swaggerDoc":"","x":103.5,"y":409,"z":"c96fb1cb.36905","wires":[["b52196bf.4ade68","292d3e2e.d6d2c2"]]},
{"id":"b52196bf.4ade68","type":"function","name":"","func":"msg.Dalert=msg.payload.Dalert;\n\nreturn msg;","outputs":1,"noerr":0,"x":326,"y":353,"z":"c96fb1cb.36905","wires":[["457cf34.fba830c","d937915d.26c87"]]},
{"id":"457cf34.fba830c","type":"dashDB in","service":"dashDB-9a","query":"select * from XXXXX.CLOUDANT WHERE DALERT=?;","params":"msg.Dalert","name":"","x":510,"y":404,"z":"c96fb1cb.36905","wires":[["60d36407.9f2c9c","886c48df.7793b8"]]},
{"id":"d937915d.26c87","type":"debug","name":"","active":false,"console":"true","complete":"payload","x":599,"y":327,"z":"c96fb1cb.36905","wires":[]},
{"id":"60d36407.9f2c9c","type":"debug","name":"","active":true,"console":"false","complete":"false","x":758,"y":397,"z":"c96fb1cb.36905","wires":[]},
{"id":"886c48df.7793b8","type":"http response","name":"","x":771,"y":477,"z":"c96fb1cb.36905","wires":[]},
{"id":"292d3e2e.d6d2c2","type":"debug","name":"","active":true,"console":"true","complete":"payload","x":321,"y":483,"z":"c96fb1cb.36905","wires":[]}
]
Please let me know if there is any solution.

Answer 1

If I understood correct your question, you just need to modify your function node with something similar to this:
msg.dalert="critical";
return msg;
Assuming your DALERT column in the CLOUDANT table is of type VARCHAR. You may need to change it if is a different type on your database.
Running the application like:
http://yourappname.mybluemix.net/get/specificcritical
will result in output similar to this for my table:
[
{
"DALERT": "critical",
"DEVICE": "device1",
"ID": 1
},
{
"DALERT": "critical",
"DEVICE": "device3",
"ID": 3
},
{
"DALERT": "critical",
"DEVICE": "device5",
"ID": 5
}
]
Here is the new node flow I created with the changes (I added an input node with blank message just to test the flow in the editor):
[{"id":"c7468303.38b98","type":"http in","name":"","url":"/get/specificcritical","method":"get","swaggerDoc":"","x":125,"y":245,"z":"8e2ae4a.f71d518","wires":[["c685ce8c.397a3","20dfeeba.df2012"]]},{"id":"c685ce8c.397a3","type":"function","name":"","func":"msg.dalert=\"critical\";\nreturn msg;","outputs":1,"noerr":0,"x":347.5,"y":189,"z":"8e2ae4a.f71d518","wires":[["e1f8c153.1e074","1f2d6f8e.e0d29"]]},{"id":"e1f8c153.1e074","type":"dashDB in","service":"dashDB-0a","query":"select * from CLOUDANT WHERE DALERT=?;","params":"msg.dalert","name":"","x":531.5,"y":240,"z":"8e2ae4a.f71d518","wires":[["f1810e4c.0e7ef","1401dc1a.ebfe24"]]},{"id":"1f2d6f8e.e0d29","type":"debug","name":"","active":false,"console":"true","complete":"payload","x":620.5,"y":163,"z":"8e2ae4a.f71d518","wires":[]},{"id":"f1810e4c.0e7ef","type":"debug","name":"dashDB Output","active":true,"console":"false","complete":"payload","x":779.5,"y":233,"z":"8e2ae4a.f71d518","wires":[]},{"id":"1401dc1a.ebfe24","type":"http response","name":"","x":792.5,"y":313,"z":"8e2ae4a.f71d518","wires":[]},{"id":"20dfeeba.df2012","type":"debug","name":"","active":true,"console":"true","complete":"payload","x":342.5,"y":319,"z":"8e2ae4a.f71d518","wires":[]},{"id":"1f530672.e0acfa","type":"inject","name":"","topic":"","payload":"","payloadType":"none","repeat":"","crontab":"","once":false,"x":122,"y":112,"z":"8e2ae4a.f71d518","wires":[["c685ce8c.397a3"]]}]

Answer 2

I got ans for question.
if we want to pass value as parameter just write msg.variable=msg.payload.variable; and return msg;
inside function node and msg.variable also declare in query parm inside dashDB IN node. eg:msg.Dalert=msg.payload.Dalert; and
critical value pass with url as http://yourappname.mybluemix.net/get/specificcritical?Dalert=critical
Its simple working node red flow
[
{"id":"9941f62b.66be08","type":"http in","name":"","url":"/get/specificcritical","method":"get","swaggerDoc":"","x":103.5,"y":409,"z":"c96fb1cb.36905","wires":[["b52196bf.4ade68","292d3e2e.d6d2c2"]]},
{"id":"b52196bf.4ade68","type":"function","name":"","func":"msg.Device=msg.payload.Device;\n\nreturn msg;","outputs":1,"noerr":0,"x":326,"y":353,"z":"c96fb1cb.36905","wires":[["457cf34.fba830c","d937915d.26c87"]]},
{"id":"457cf34.fba830c","type":"dashDB in","service":"dashDB-XX","query":"select * from XXXXX.CLOUDANT WHERE DEVICE=?","params":"msg.Device","name":"","x":510,"y":404,"z":"c96fb1cb.36905","wires":[["60d36407.9f2c9c","886c48df.7793b8"]]},
{"id":"d937915d.26c87","type":"debug","name":"","active":false,"console":"true","complete":"payload","x":599,"y":327,"z":"c96fb1cb.36905","wires":[]},
{"id":"60d36407.9f2c9c","type":"debug","name":"","active":true,"console":"false","complete":"false","x":758,"y":397,"z":"c96fb1cb.36905","wires":[]},
{"id":"886c48df.7793b8","type":"http response","name":"","x":771,"y":477,"z":"c96fb1cb.36905","wires":[]},
{"id":"292d3e2e.d6d2c2","type":"debug","name":"","active":true,"console":"true","complete":"payload","x":321,"y":483,"z":"c96fb1cb.36905","wires":[]}
]