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MongoDB Articles
Page 77 of 111
Find all documents that have two specific id's in an array of objects in MongoDB?
To find all documents that have two specific id's in an array of objects in MongoDB, use the $and operator with dot notation to match multiple values within the same array field. Syntax db.collection.find({ $and: [ { "arrayField.property": value1 }, { "arrayField.property": value2 } ] }); Sample Data db.twoSpecificIdsDemo.insertMany([ { PlayerId: 1, ...
Read MoreMongoDB pull with positional operator?
The $pull operator combined with the positional operator ($) in MongoDB allows you to remove specific values from arrays within nested documents. Use $elemMatch to identify the target document and $ to reference the matched array element. Syntax db.collection.update( { "arrayField": { "$elemMatch": { "field": "matchValue" ...
Read MoreSearch a sub-field on MongoDB?
To search a sub-field in MongoDB, use dot notation with the field path enclosed in double quotes. This allows you to query nested fields within embedded documents. Syntax db.collection.find({"parentField.subField": "value"}); Sample Data db.searchSubFieldDemo.insertMany([ { "UserDetails": { "UserEmailId": "John123@gmail.com", "UserAge": 21 } }, ...
Read MoreHow to define aliases in the MongoDB Shell?
To define aliases in the MongoDB shell, you can create shortcuts for frequently used functions or expressions using Object.defineProperty(). This allows you to create reusable commands with custom names. Syntax Object.defineProperty(this, 'yourFunctionName', { get: function() { // your statements here return someValue; }, enumerable: true, configurable: true }); To assign the alias to a variable: var anyAliasName = yourFunctionName; Example Let's create an alias called displayMessageDemo ...
Read MoreHow to check if a field in MongoDB is [] or {}?
To check if a field in MongoDB is an empty array [] or an empty object {}, you can use the $size operator for arrays and $eq operator for objects to identify these specific empty states. Syntax // Check for empty object {} db.collection.find({ "fieldName": {} }); // Check for empty array [] db.collection.find({ "fieldName": { $size: 0 } }); // Check for both empty array or empty object db.collection.find({ $or: [ { "fieldName": {} }, ...
Read MoreHow to get all collections where collection name like '%2015%'?
To get all collections where the collection name contains a specific pattern like '%2015%', you can use MongoDB's getCollectionNames() method combined with JavaScript's filter() function and regular expressions. Creating Sample Collections Let us first create some collections that contain year numbers like 2015, 2019, etc ? > use web; switched to db web > db.createCollection("2015-myCollection"); { "ok" : 1 } > db.createCollection("2019-employeeCollection"); { "ok" : 1 } > db.createCollection("2015-yourCollection"); { "ok" : 1 } Now you can display all the collections with the help of SHOW command ? > show collections; ...
Read MoreMongoDB query to fetch elements between a range excluding both the numbers used to set range?
To fetch elements between a range in MongoDB while excluding both boundary numbers, use the $gt (greater than) and $lt (less than) operators together in your query. Syntax db.collectionName.find({ fieldName: { $gt: lowerBound, $lt: upperBound } }); For including both boundary numbers, use $gte and $lte operators ? db.collectionName.find({ fieldName: { $gte: lowerBound, $lte: upperBound } }); Sample Data db.returnEverythingBetween50And60.insertMany([ {"Amount": 55}, {"Amount": 45}, {"Amount": 50}, ...
Read MoreCan MongoDB return result of increment?
Yes, MongoDB can return the result of an increment operation using the findAndModify() method. This allows you to atomically increment a value and retrieve the updated document in a single operation. Syntax db.collection.findAndModify({ query: { /* match criteria */ }, update: { $inc: { "field": incrementValue } }, new: true }); Sample Data Let us first create a collection with a sample document: db.returnResultOfIncementDemo.insertOne({"PlayerScore": 98}); { "acknowledged": true, "insertedId": ...
Read MoreGet the size of all the documents in a MongoDB query?
To get the size of all the documents in a MongoDB query, you need to loop through the documents and calculate their cumulative BSON size using Object.bsonsize() method. Syntax var cursor = db.collection.find(); var totalSize = 0; cursor.forEach(function(doc) { totalSize += Object.bsonsize(doc); }); print(totalSize); Sample Data db.sizeOfAllDocumentsDemo.insertMany([ { "StudentFirstName": "John", "StudentSubject": ["MongoDB", "Java"] }, { ...
Read MoreHow to insert an 8-byte integer into MongoDB through JavaScript shell?
To insert an 8-byte integer into MongoDB through JavaScript shell, use the NumberLong() constructor to create a 64-bit integer value. This ensures proper storage of large integer values that exceed JavaScript's standard number precision. Syntax anyVariableName = {"yourFieldName": new NumberLong("yourValue")}; Example Create a variable with an 8-byte integer ? userDetail = {"userId": new NumberLong("98686869")}; { "userId" : NumberLong(98686869) } Display Variable Value Display the variable using the variable name ? userDetail { "userId" : NumberLong(98686869) } Display the variable ...
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