In my JSON results, I'm trying to see if a particular object exists, and if it does exist, what is the count. I'm using length expression but it seems to be failing for me with error:
The template function 'lenth' is not defined or not valid.
Here is my Get_Ticket object:
{
"TicketInfo": {
"key1": "val1",
"key2": "val2",
"key3": "val3"
},
"TicketEquipmentInfo": [{
"EquipKey1": "val1",
"EquipKey2": "val2"
}, {
"EquipKey1": "val3",
"EquipKey2": "val3"
}]
}
Here is my expression:
if(contains(body('Get_Ticket'), 'TicketEquipmentInfo'), if(greater(lenth(body('Get_Ticket')['TicketEquipmentInfo']), 0), 'Found at least 1 piece of Equipment', '<leave blank, empty array found>'), '<leave blank, no array found>')
What am I doing wrong? Also open to suggestions to make this expression more efficient without having to modify the logic app design.
There's a typo - use not lenth but length.
Related
I am looking for an array of ids, inside another array, the problem is that if it contains at least one "id" it returns the result. The validation should be that it has to have all the "ids" that I am passing.
{ subcategories: { $in: [ ObjectId('61729d550e8fe20011cc57d2', ObjectId('61693f589a34340012b1d5d8'), ObjectId('61693f2c9a34340012b1d5b7') )] } }
example:
subcategories: ["61729d550e8fe20011cc57d2", "61693f2c9a34340012b1d5b7"] -> this one should not appear, because it contains only 2 of the 3 I am looking for
I think you are looking for $all.
The docs says:
The $all operator selects the documents where the value of a field is an array that contains all the specified elements
db.collection.find({
subcategories: {
$all: [
"61729d550e8fe20011cc57d2",
"61693f589a34340012b1d5d8",
"61693f2c9a34340012b1d5b7"
]
}
})
Example here
Consider the following MongoDB collection of a few thousand Objects:
{
_id: ObjectId("xxx")
FM_ID: "123"
Meter_Readings: Array
0: Object
Date: 2011-10-07
Begin_Read: true
Reading: 652
1: Object
Date: 2018-10-01
Begin_Reading: true
Reading: 851
}
The wrong key was entered for 2018 into the array and needs to be renamed to "Begin_Read". I have a list using another aggregate of all the objects that have the incorrect key. The objects within the array don't have an _id value, so are hard to select. I was thinking I could iterate through the collection and find the array index of the errored Readings and using the _id of the object to perform the $rename on the key.
I am trying to get the index of the array, but cannot seem to select it correctly. The following aggregate is what I have:
[
{
'$match': {
'_id': ObjectId('xxx')
}
}, {
'$project': {
'index': {
'$indexOfArray': [
'$Meter_Readings', {
'$eq': [
'$Meter_Readings.Begin_Reading', True
]
}
]
}
}
}
]
Its result is always -1 which I think means my expression must be wrong as the expected result would be 1.
I'm using Python for this script (can use javascript as well), if there is a better way to do this (maybe a filter?), I'm open to alternatives, just what I've come up with.
I fixed this myself. I was close with the aggregate but needed to look at a different field for some reason that one did not work:
{
'$project': {
'index': {
'$indexOfArray': [
'$Meter_Readings.Water_Year', 2018
]
}
}
}
What I did learn was the to find an object within an array you can just reference it in the array identifier in the $indexOfArray method. I hope that might help someone else.
I'm using MongoDb. I'm trying to execute a query to search a collection and return all documents that match a list of names (strings).
Here is my query:
{
db.employees.find({ "n": { "$in": ["Alice", "Mary"]}})
}
But I'm getting the error:
"Field names in dot notation need to be in quotes at line 2, col 22"
Which is the character before "n". What gives? Thanks!
I figured it out doh. When using studio 3t, the collection is implicitly implied. As such, you only need to type:
{ "n": { "$in": ["Alice", "Mary"]}}
not
db.employees.find({ "n": { "$in": ["Alice", "Mary"]}})
Silly error, leaving this up in case someone finds it useful
MongoDB seems to interpret $set paths with numerical components as object keys rather than array indexes if the field has not already been created as an array.
> db.test.insert({_id: "one"});
> db.test.update({_id: "one"}, {$set: {"array.0.value": "cheese"}});
> db.find({_id: "one"})
{ "_id": "one", "array": { "0" : { "value" : "cheese" } }
I expected to get "array": [{"value": "cheese"}], but instead it was initialized as an object with a key with the string "0".
I could get an array by initializing the whole array, like so:
> db.test.update({_id: "one"}, {$set: {"array": [{"value": "cheese"}]}});
... but this would clobber any existing properties and other array elements that might have been previously set.
Is there any way to convince $set that I want "array" to be an array type, with the following constraints:
I want to execute this in a single query, without looking up the record first.
I want to preserve any existing array entries and object values
In short, I want the behavior of $set: {"array.0.value": ... } if "array" had already been initialized as an array, without knowing whether or not it has. Is this possible?
I am not sure if this is possible without lookup. Perhaps you can change schema design, and try something like this:
db.test.insert({_id: "one"});
db.test.update({_id: "one"}, {$addToSet: {array: { $each:['cheese', 'ham'] }}});
db.test.findOne({_id:'one'});
// { "_id" : "one", "array" : [ "cheese", "ham" ] }
Handling array elements (sub-documents in array) in MongoDb is pain. https://jira.mongodb.org/browse/SERVER-1243
I'd like to be able to query documents where an array attribute is either null or of zero length. I've tried using $or, like
{ things : { $or : [null, { $size : 0 } ] } }
but MongoDB complains about it:
{ "$err" : "invalid operator: $or", "code" : 10068 }
It appears that MongoDB doesn't want to use $and or $or on array attributes. I thought that simply querying for { things : { $size : 0 } } would return documents that had non-null arrays of zero length as well as null arrays, but that doesn't appear to be true.
How can I issue a query to find all documents where an array attribute is null or of zero length?
You can also do this with $in:
db.test.find({things: {$in: [null, []]}})
That will also include docs with things: [null].
Another way is to use $exists on the first element of the things array:
db.test.find({'things.0': {$exists: false}})
That will find the docs where things does not have at least one element. In contrast with the above, it will still include docs with things: null or things: [], but not things: [null].
When things is null, it is not of type Array. It is of type Null which is its own data-type. $size only matches arrays. Any document where the field is something different than an array will never be matched by it.
Your syntax error is in how you use the $or operator. You don't use it for a field, you use it as a field.
db.collection.find({
$or: [
{ things: { $size: 0 } }, // 0-elements array
{ things: null } // field which is null
]
});