MongoDB will not create an index on a collection if the index entry for an existing document exceeds the index key limit (1024 bytes). You can however create a hashed index or text index instead: db.logcollection.createIndex({“Module”:”hashed”}) or db.logcollection.createIndex({“Module”:”text”})
Yes it’s possible. You just use $geoNear instead. Beware the catches and read carefully. Presuming that your intent to is to store a field such as “travelDistance” to indicate on the document that any such searches must be “within” that supplied distance from the queried point to be valid. Then we simply query and evaluate … Read more
One way to do it is use $setWindowFields: db.collection.aggregate([ { $setWindowFields: { output: { totalCount: {$count: {}} } } }, { $unwind: “$items” }, { $group: { _id: “$items.defindex”, count: {$sum: 1}, totalCount: {$first: “$totalCount”} } }, { $project: { count: 1, usage: {$divide: [“$count”, “$totalCount”] } } }, {$sort: {count: -1}} ]) As you … Read more
You don’t need to use to retrieve the document first just use the .update method with the $push operator. def update_tags(ref, new_tag): coll.update({‘ref’: ref}, {‘$push’: {‘tags’: new_tag}}) Since update is deprecated you should use the find_one_and_update or the update_one method if you are using pymongo 2.9 or newer
This answer is outdated. Since version 3.2, MongoDB has limited support for left outer joins with the $lookup aggregation operator MongoDB does not do queries which span multiple collections – period. When you need to join data from multiple collections, you have to do it on the application level by doing multiple queries. Query collection … Read more
Few problems, you created your indexes on the foo collection of the foo database, but are querying the bar collection. You need to be on the correct collection. Reading the document you have inserted you need to add a “2dsphere” index to support the geoJson objects. This index needs to be on the “point” element … Read more
After running some queries, I came to the conclusion that $in doesn’t work for an array of arrays. You can use $elemMatch instead and it’ll work, but it is frustrating that MongoDB’s documentation doesn’t warn about it. I created this document: { “_id”: “51cb12857124a215940cf2d4”, “level1”: [ [ “item00”, “item01” ], [ “item10”, “item11” ] ], … Read more
This is a rehash of the previous answer but it’s more likely to work on different mongodb versions. db.collection.find().limit(1).sort({$natural:-1})
Check if this solution meets your requirements. Explanation We join over the same collection. So for each item i we take item i+1. This method gives us where presenceStatus has been changed. We filter documenti i+1 pairs where presenceStatus is 0 – 1 or 1 – 0. We group them into single data array. Now … Read more
Use $dateToParts and its counterpart $dateFromParts Here is an updated Playground What it does is basically break the date into its parts: { $project: { dateHour: { $dateToParts: { date: “$updatedAt” } } } } would produce: { “dateHour”: { “day”: 19, “hour”: 18, “millisecond”: 0, “minute”: 21, “month”: 3, “second”: 5, “year”: 2020 } … Read more