Im a student just starting out on NoSQL and its just not clicking with me. im a little confused on a few points.
Any help would be greatly appreciated
1.Can documents belong to multiple collections?
2.Have I the correct syntax here for creating the Collection?
The pic is the collection er and a is just a snippet of the full er.
db.Animal.insert ( {
“animal_ID” : “XXXXXXX “,
“common_name” : “Red Squirrel”,
“IUCN” : “Least Concern (declining)”,
“photo” : “qs451xkx6qf4j”,
“extinct” : {
“when” : “null “,
“reason” : “null”
},
“invasive” : {
“threat_level” : “null”,
“threat” : “null”,
“how_to_help” : “null”
},
“native” : {
“endangerment” : “population declining“,
“how_to_help” : “providing a little extra food, planting some red squirrel-friendly shrubs and reporting any red or grey squirrel activity”
},
“Fact_sheet” : “{
“fact_id” : “ “,
“animal_id” : “ XXXXXXX “,
“order” : “ Rodentia “,
“family” : “Sciuridae “ ,
“species” : “Sciurus vulgaris “ ,
“size” : “body length 19 to 23 cm, tail length 15 to 20 cm “ ,
“weight” : “250 to 340 g “ ,
“lifespan” : “3 years , 7 to 10 in captivity “ ,
“extra” : “In Norse mythology, Ratatoskr is a red squirrel who runs up and down with messages in the world tree, Yggdrasil, and spreads gossip “ ,
“habitat” : { [
“name” : “woodland “,
“description” : “a low-density forest forming open habitats with plenty of sunlight and limited shade “
]
});
Can documents belong to multiple collections?
In MongoDB, no. In other databases, I don't know.
2.Have I the correct syntax here for creating the Collection?
To create a collection you would use https://docs.mongodb.com/manual/reference/method/db.createCollection/. This call also permits you to pass various collection options.
You are inserting a document. In MongoDB when a document is inserted, if the destination collection doesn't exist, it is created automatically by the server.
I want to order an array. The JSONata expression below has an incoming array as follows.
[{"id":"Air-1a",
"Controller":"ESP62",
"Cntr-TaskNo":10,
"Cntr-GPIO":13,
"name":"Air",
"valueName":"Humidity",
"Sensor":"DHT22",
(and many other key pairs)},
{next object}, ...]
I then transform the array with the following JSONata expression:
payload.(
{ "Controller" : $.Controller,
"Cntr-TaskNo": $.CntrDef.TaskNo,
"Cntr-GPIO" : $.CntrDef.GPIO,
"name" : $.name,
"valueName" : $.valueName,
"Sensor" : $.Sensor,
"id" : $.id
}
)
But now I want to - in the same JSONata expression, sort on firstly the Controller, and then the GPIO. To tried with the Controller only first.
I tried:
payload.(
{ $sort("Controller",function($l, $r){$l.Controller > $r.Controller}) : $.Controller ,
"Cntr-TaskNo": $.CntrDef.TaskNo,
"Cntr-GPIO" : $.CntrDef.GPIO,
"name" : $.name,
"valueName" : $.valueName,
"Sensor" : $.Sensor,
"id" : $.id
}
)
As well as trying to add the sort function at the end with the ~> chaining command. I also tried the order-by operator.
Could anyone point me in the right direction?
//----------
The new flow with the changed 'ESP62' to '-' that does not work:
[{"id":"874b0c77.f87418","type":"inject","z":"6f27a311.d135bc","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":200,"y":180,"wires":[["8c196590.c20638"]]},{"id":"8c196590.c20638","type":"change","z":"6f27a311.d135bc","name":"Dataset","rules":[{"t":"set","p":"payload","pt":"msg","to":"[{\"id\":\"Air-1a\",\"Controller\":\"ESP62\",\"CntrTaskNo\":10,\"CntrGPIO\":13,\"name\":\"Air\",\"valueName\":\"Humidity\",\"Sensor\":\"DHT22\",\"aaa\":\"111\",\"bbb\":\"222\",\"ccc\":\"333\"},{\"id\":\"Air-2a\",\"Controller\":\"ESP72\",\"CntrTaskNo\":11,\"CntrGPIO\":14,\"name\":\"Air\",\"valueName\":\"Humidity\",\"Sensor\":\"DHT22\",\"aaa\":\"444\",\"bbb\":\"555\",\"ccc\":\"666\"},{\"id\":\"Air-1a\",\"Controller\":\"ESP62\",\"CntrTaskNo\":2,\"CntrGPIO\":9,\"name\":\"Air\",\"valueName\":\"Humidity\",\"Sensor\":\"DHT22\",\"aaa\":\"777\",\"bbb\":\"888\",\"ccc\":\"999\"},{\"id\":\"Air-1a\",\"Controller\":\"-\",\"CntrTaskNo\":10,\"CntrGPIO\":12,\"name\":\"Air\",\"valueName\":\"Humidity\",\"Sensor\":\"DHT22\",\"aaa\":\"777\",\"bbb\":\"888\",\"ccc\":\"999\"}]","tot":"json"}],"action":"","property":"","from":"","to":"","reg":false,"x":360,"y":180,"wires":[["13981162.14e28f"]]},{"id":"c8a256a5.a170c8","type":"debug","z":"6f27a311.d135bc","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":690,"y":180,"wires":[]},{"id":"13981162.14e28f","type":"change","z":"6f27a311.d135bc","name":"Jsonata $sort","rules":[{"t":"set","p":"payload","pt":"msg","to":"($sort(payload,function($l , $r){$l.Controller > $r.Controller}) ; \t$sort(payload,function($l , $r){$l.CntrGPIO > $r.CntrGPIO}))","tot":"jsonata"}],"action":"","property":"","from":"","to":"","reg":false,"x":520,"y":180,"wires":[["c8a256a5.a170c8"]]}]
I suggest first sorting the dataset and afterward transform the already sorted array of objects. The transformation is trivial and you want to know how to sort, so I show below one possible solution. It uses an expression with two concatenated $sort functions.
Edited after a better understanding of the requirement.
I tested successfully a Node-RED flow using this expression in a change node:
($a := $sort(payload,function($l , $r){$l.Controller > $r.Controller}) ; $sort($a,function($l , $r){(($l.Controller = $r.Controller) and ($l.CntrGPIO > $r.CntrGPIO))}))
Flow (contain dataset set hardcoded):
[{"id":"a7814b7e.3adeb8","type":"tab","label":"Flow 4","disabled":false,"info":""},{"id":"8bf10833.c71748","type":"inject","z":"a7814b7e.3adeb8","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":140,"y":140,"wires":[["9e365564.edca08"]]},{"id":"9e365564.edca08","type":"change","z":"a7814b7e.3adeb8","name":"Dataset","rules":[{"t":"set","p":"payload","pt":"msg","to":"[{\"id\":\"Air-1a\",\"Controller\":\"ESP62\",\"CntrTaskNo\":10,\"CntrGPIO\":13,\"name\":\"Air\",\"valueName\":\"Humidity\",\"Sensor\":\"DHT22\",\"aaa\":\"111\",\"bbb\":\"222\",\"ccc\":\"333\"},{\"id\":\"Air-2a\",\"Controller\":\"ESP72\",\"CntrTaskNo\":11,\"CntrGPIO\":14,\"name\":\"Air\",\"valueName\":\"Humidity\",\"Sensor\":\"DHT22\",\"aaa\":\"444\",\"bbb\":\"555\",\"ccc\":\"666\"},{\"id\":\"Air-1a\",\"Controller\":\"ESP62\",\"CntrTaskNo\":2,\"CntrGPIO\":9,\"name\":\"Air\",\"valueName\":\"Humidity\",\"Sensor\":\"DHT22\",\"aaa\":\"777\",\"bbb\":\"888\",\"ccc\":\"999\"},{\"id\":\"Air-1a\",\"Controller\":\"-\",\"CntrTaskNo\":10,\"CntrGPIO\":12,\"name\":\"Air\",\"valueName\":\"Humidity\",\"Sensor\":\"DHT22\",\"aaa\":\"777\",\"bbb\":\"888\",\"ccc\":\"999\"}]","tot":"json"}],"action":"","property":"","from":"","to":"","reg":false,"x":300,"y":140,"wires":[["762f6421.074fec"]]},{"id":"f827bddb.c9acd","type":"debug","z":"a7814b7e.3adeb8","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":630,"y":140,"wires":[]},{"id":"762f6421.074fec","type":"change","z":"a7814b7e.3adeb8","name":"Jsonata $sort","rules":[{"t":"set","p":"payload","pt":"msg","to":"($a := $sort(payload,function($l , $r){$l.Controller > $r.Controller}) ; $sort($a,function($l , $r){(($l.Controller = $r.Controller) and ($l.CntrGPIO > $r.CntrGPIO))}))","tot":"jsonata"}],"action":"","property":"","from":"","to":"","reg":false,"x":460,"y":140,"wires":[["f827bddb.c9acd"]]}]
also tested in Jsonata exerciser: http://try.jsonata.org/S1IlT3y-E
You can sort the array using the following expression:
payload^(Controller, CntrDef.GPIO)
The order-by operator ^ will sort the array, first by increasing value of Controller, then by increasing value of CntrGPIO. You can then transform each object within that array
payload^(Controller, CntrDef.GPIO).{
"Controller" : Controller,
"Cntr-TaskNo": CntrDef.TaskNo,
"Cntr-GPIO" : CntrDef.GPIO,
"name" : name,
"valueName" : valueName,
"Sensor" : Sensor,
"id" : id
}