I am working on a Mongo database, where I need users to be able to specify dates when they won't be available. I started with this structure:
{
"_id": "demo-spe",
"SC": [ { "SS": 14, "SA": [ 2, 3, 5 ] } ],
"SU": [
{ "IY": 2013, "IM": 12, "ID": 30, "H0": 0, "N0": 0, "H1": 23, "N1": 59 },
{ "IY": 2013, "IM": 12, "ID": 31, "H0": 0, "N0": 0, "H1": 23, "N1": 59 }
]
}
Using this structure, if I want to know which users will be available on a certain date, that is, the "SU" array should NOT have a document that matches IY:(year), IM:(month) and ID:(day). I am really lost with $and and $nin, could please someone guide me?
Thanks, and sorry for the noob question and the non-descriptive fields! :)
You can use a combination of $elemMatch and $not to do this. $elemMatch to match against multiple fields in the same array element, and $not to perform a logical NOT on the expression:
db.test.find({SU: {$not: {$elemMatch: {IY:2013, IM:12, ID:29}}}})
Related
DB collection seatsObj:
{
"product_id": 46539040,
"freeSeating": false,
"tempTransId": "1ecae165f2d86315fea19963d0ded41a",
"seatLayout": {
"colAreas": {
"Count": 2,
"intMaxSeatId": 43,
"intMinSeatId": 2,
"objArea": [
{
"AreaDesc": "EXECUTIVE",
"AreaCode": "0000000003",
"AreaNum": "1",
"HasCurrentOrder": true,
"objRow": [
{
"GridRowId": 1,
"PhyRowId": "A",
"objSeat": [
{
"GridSeatNum": 1,
"SeatStatus": "1",
"seatNumber": 1,
"seatPrice": 400,
"ID": 111
},
{
"GridSeatNum": 2,
"SeatStatus": "0",
"seatNumber": 2,
"seatPrice": 450,
"ID": 112
},
I was able to find ways to locate and update specific fields using:
seatsObj.updateOne(
{"seatLayout.colAreas.objArea.0.objRow.0.objSeat.seatPrice": 470},
{$set: {"seatLayout.colAreas.objArea.0.objRow.0.objSeat.$.ID": 888}});
but i cannot find simple way to return a specific field value from objSeat array element based on search criteria (for example: get 400 as a result of querying seatPrice for the seat with ID = 111). Could anyone give me a direction? From my initial research I have to go into crazy nested $unwind -s and $objectToArray -s, etc... Isn't there a simpler way? Thank you!!
My database looks like this:
{
_id: 1,
values: [ 1, 2, 3, 4, 5 ]
},
{
_id: 2,
values: [ 2, 4, 6, 8, 10 ]
}, ...
I'd like to update every value in every document's nested array ("values") that meets some criterion. For instance, I'd like to increment every value that's >= 4 by one, which ought to yield:
{
_id: 1,
values: [ 1, 2, 3, 5, 6 ]
},
{
_id: 2,
values: [ 2, 5, 7, 8, 11 ]
}, ...
I'm used to working with SQL, where the nested array would be a seperated table connected with a unique ID. I'm a little lost in this new NoSQL world.
Thank you kindly,
This sort of update is not really possible using nested arrays, the reason for this is given in the positional $ operator documentation, and that states that you can only match the first array element for a given condition in the query.
So a statement like this:
db.collection.update(
{ "values": { "$gte": 4 } },
{ "$inc": { "values.$": 1 } }
)
Will not work in the sense that only the "first" array element that was matched would be incremented. So on your first document you would get this:
{ "_id" : 1, "values" : [ 1, 2, 3, 6, 6 ] }
In order to update the values as you are suggesting you would need to iterate the documents and the array elements to produce the result:
db.collecction.find({ "values": { "$gte": 4 } }).forEach(function(doc) {
for ( var i=0; i < doc.values.length; i++ ) {
if ( doc.values[i] >= 4 ) {
doc.values[i]++;
}
}
db.collection.update(
{ "_id": doc._id },
{ "$set": { "values": doc.values } }
);
})
Or whatever code equivalent of that basic concept.
Generally speaking, this sort of update does not lend itself well to a structure that contains elements in an array. If that is really your need, then the elements are better off listed within a separate collection.
Then again, the presentation of this question is more of a "hypothetical" situation without understanding your actual use case for performing this sort of udpate. So if you possibly described what you actually need to do and how your data really looks in another question, then that might get a more meaningful response in terms of the best approach for you to use.
H,
I'm trying to update the version field in this object but I'm not able to make a query with 2 nested $match. So what I would like to do is get the record with file id 12 and version 1.
I would ask also if is it a good practice have more the one nested array in mongoDB (like this object)...
Query:
db.collection.find({"my_uuid":"434343"},{"item":{$elemMatch:{"file_id":12,"changes":{$elemMatch:{"version":1}}}}}).pretty()
Object:
{
"my_uuid": "434343",
"item": [
{
"file_id": 12,
"no_of_versions" : 1,
"changes": [
{
"version": 1,
"commentIds": [
4,
5,
7
]
},
{
"version": 2,
"commentIds": [
10,
11,
15
]
}
]
},
{
"file_id": 234,
"unseen_comments": 3,
"no_of_versions" : 2,
"changes": [
{
"version": 1,
"commentIds": [
100,
110,
150
]
}
]
}
]
}
Thank you
If you want the entire documents that satisfy the criteria returned in the result, then I think it's fine. But if you want to limit the array contents of item and changes to just the matching elements, then it could be a problem. That's because, you'll have to use the $ positional operator in the projection to limit the contents of the array and only one such operator can appear in the projection. So, you'll not be able to limit the contents of multiple arrays within the document.
I'm learning mongo and I have this schema below and i would like some help defining a query:
I would like to get the sum of the "entregado" fields that match this code: 151001. In this case i would get this result = 38.
Do I need to change the schema or is easy to get a query for what i want?
{
"_id": 101,
"torre": 1,
"standard": {
"mamposteria": [
{
"codigo": 311017,
"descripcion": "LADRILLO ARCILLA H-10",
"cantidad": 1080,
"um": "UN",
"entregado": 1080,
"fecha": new Date('June 10, 2013'),
"vale": [1322]
},
{
"codigo": 311021,
"descripcion": "LADRILLO ARCILLA H-7",
"cantidad": 200,
"um": "UN",
"entregado": 200,
"fecha": new Date('June 10, 2013'),
"vale": [1322]
},
{
"codigo": 151001,
"descripcion": "CEMENTO GRIS 50 KG",
"cantidad": 17,
"um": "KG",
"entregado": 17,
"fecha": new Date('June 10, 2013'),
"vale": [1322]
}
],
"mortero": [
// . . .
],
"estructura":[
// . . .
]
}
}
To get the count alone u don't need to modify your schema.
Just following the below steps can give you the count what u need. I will not give you the whole query to find the count. That makes u lazy..so will give steps to get the count...
1) use $unwind 2) use $match to find the value for code: 151001 3) use $group to $sum the values present in entregado
This should give you the count.
If you need any other help pls contact me I will help
I know this question has been asked before, but that's a different scenario.
I'd like to have a collection like this:
{
"_id" : ObjectId("4c28f62cbf8544c60506f11d"),
"pk": 1,
"forums": [{
"pk": 1,
"thread_count": 10,
"post_count": 20,
}, {
"pk": 2,
"thread_count": 5,
"post_count": 24,
}]
}
What I want to do is to upsert a "forum" item, incrementing counters or adding an item if it does not exist.
For example to do something like this (I hope it makes sense):
db.mycollection.update({
"pk": 3,
"forums.pk": 2
}, {
"$inc": {"forums.$.thread_count": 1},
"$inc": {"forums.$.post_count": 1},
}, true)
and have:
{
"_id" : ObjectId("4c28f62cbf8544c60506f11d"),
"pk": 1,
"forums": [{
"pk": 1,
"thread_count": 10,
"post_count": 20,
}, {
"pk": 2,
"thread_count": 5,
"post_count": 24,
}]
},
{
"_id" : ObjectId("4c28f62cbf8544c60506f11e"),
"pk": 3,
"forums": [{
"pk": 2,
"thread_count": 1,
"post_count": 1,
}]
}
I can surely make it in three steps:
Upsert the whole collection with a new item
addToSet the forum item to the list
increment forum item counters with positional operator
That's to say:
db.mycollection.update({pk:3}, {pk:3}, true)
db.mycollection.update({pk:3}, {$addToSet: {forums: {pk:2}}})
db.mycollection.update({pk:3, 'forums.pk': 2}, {$inc: {'forums.$.thread_counter': 1, {'forums.$.post_counter': 1}})
Are you aware of a more efficient way to do it?
TIA, Germano
As you may have discovered, the positional operator cannot be used in upserts:
The positional operator cannot be combined with an upsert since it requires a matching array element. If your update results in an insert then the "$" will literally be used as the field name.
So you won't be able to achieve the desired result in a single query.
You have to separate the creation of the document from the counter update. Your own solution is on the right track. It can be condensed into the following two queries:
// optionally create the document, including the array
db.mycollection.update({pk:3}, {$addToSet: {forums: {pk:2}}}, true)
// update the counters in the array item
db.mycollection.update({pk:3, 'forums.pk': 2}, {$inc: {'forums.$.thread_counter': 1, 'forums.$.post_counter': 1}})