mongodb-query

问题 I got a collection with documents such as those: { "_id": 0, "pictures": [ { "path": "/path/to/first/picture.jpg", "web": "true" }, { "path": "/path/to/second/picture.jpg", "web": "true", } ], "logos": [ { "path": "/path/to/first/logo.jpg", "web": "true" }, { "path": "/path/to/second/logo.jpg", "web": "false", } ] } { "_id": 1, "pictures": [ { "path": "/a/bit/weird/path/to/picture.jpg", "web": "false" }, { "path": "/another/weird/path/to/picture.jpg", "web": "false", } ], "logos": [ { "path":

问题 I seem to have run into a roadblock while using MongoDB, and would like to know if there is anyway around it without having to modify my database structure. Right now my database structure is as follows: Company= { _id:1, properties:[ { property_id: 1 tags : [ { tag_id: 1 tag_value: 1000 channels: [ { channel_id:1 channel_name:"test1" }, { channel_id:2 channel_name:"test2" }] }, { tag_id:2 tag_value: 2500 channels: [ { channel_id:2 channel_name:"test2" }, { channel_id:3 channel_name:"test3" }

问题 Is there a possibility to use the full text search of mongoDB with the haskell driver? I found the 'runCommand' in the haskell API, but it expects a Document as parameter. That's fine for all the other commands that mongodb can run, but the syntax for a text command is: db.collection.runCommand( "text", {search : "something"}) So I don't know how I'll get the "text" as first parameter in front of the Document. Thanks 回答1: The text -command can be written in another structure: { text: your

问题 How to write simial query using mongdoDb aggregation select count(*) as ccount from a group by a.someField order by ccount desc limit 1 Using group function in mondoDb, I want to group my collection by specific key and return 1 row, which occurs more often Code below in Java, return list, that was apply group by on field someField and return collection of elements, where every element has 2 fields, "someField" and "count" (number of occurrence) I would like to avoid second iteration on client

问题 We are using morphia 0.99 and java driver 2.7.3 I would like to learn is there any difference between fetching records one by one using fetch and retrieving results by asList (assume that there is enough memory to retrieve records through asList ). We iterate over a large collection, while using fetch I sometimes encounter cursor not found exception on the server during the fetch operation, so I need to execute another command to continue, what could be the reason for this? 1-)fetch the

问题 So In my express app, I am trying to find() based on my _id field. See my MongoDB record below. { "_id": { "$oid": "58c2a5bdf36d281631b3714a" }, "title": "EntertheBadJah", "subTitle": "Lorem ipsum dolor", "thmbNailImg": "", "headerImg": "", ... BLAH BLAH BLAH When I use .find( _id: id ) , my id param = 58c2a5bdf36d281631b3714a . How would I convert / use this to get my MongoDB record? Here is my Express call: //GET ARTICLE app.get('/api/article', (req, res) => { var id = req.query.id var

问题 { "_id": "1", "style": "13123", "category": "dress", "colors": { "Black": { "prestock": 50, "instock": 60, "inactive": 0 }, "Blue": { "prestock": 30, "instock": 0, "inactive": 0 }, "Red": { "prestock": 10, "instock": 60, "inactive": 0 } } } i have above json, i need to access to prestock, instock, and inactive. but colors' value will change depending on styles. for example: { "_id": "2", "style": "14321", "category": "top", "colors": { "Green": { "prestock": 50, "instock": 60, "inactive": 0 }

问题 I'm having a problem with a group when there is an array that could be empty . The collection could be like this: { "_id" : "Contract_1", "ContactId" : "Contact_1", "Specifications" : [ ] } { "_id" : "Contract_2", "ContactId" : "Contact_2", "Specifications" : [ { "Description" : "Descrizione1", "VehicleId" : "Vehicle_1", "Customizations" : [ { "Description" : "Random furniture", "ContactId" : "Contact_5" }, { "Description" : "Random furniture 2", "ContactId" : "Contact_3" } ] }, {

问题 My collection has an array of values, but I'd like to retrieve only the last X. Example: db.collection.find({ "array": [0,1,2,3,4,5] }) And I'd like to query the last 3. How would I go about that? I'm using MongoDB and this is meant for a Meteor application. 回答1: You need to use the $slice operator. db.collection.find( { /* filter */ }, { "array": { "$slice": -3 } } ); 来源： https://stackoverflow.com/questions/34228375/limit-number-of-values-in-a-field-using-mongodb

问题 I have this test collection in my test database. [test] 2014-02-11 18:01:33.970 >>> db.test.find (); { "_id" : ObjectId("52faa8a695fa10cc7d2b7908"), "x" : 1 } { "_id" : ObjectId("52faa8ab95fa10cc7d2b7909"), "x" : 5 } { "_id" : ObjectId("52faa8ad95fa10cc7d2b790a"), "x" : 15 } { "_id" : ObjectId("52faa8b095fa10cc7d2b790b"), "x" : 25 } { "_id" : ObjectId("52faa8b795fa10cc7d2b790c"), "x" : [ 5, 25 ] } If I create an ascending index on the x field with [test] 2014-02-11 18:01:50.615 >>> db.test