Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Big Data Analytics Articles
Page 10 of 135
Set condition in MongoDB nested document?
To set conditions in MongoDB nested documents, use dot notation to navigate through the nested structure and apply comparison operators like $gt, $lt, or $eq to filter documents based on nested field values. Syntax db.collection.find({ "parentField.nestedField.deepField": { $operator: value } }); Sample Data db.demo688.insertMany([ { information: { id: 1, details: [ ...
Read MoreAccessing inner element of JSON array in MongoDB?
To access inner element of JSON array in MongoDB, use dot notation to traverse through nested objects and arrays. This allows you to query and filter documents based on deeply nested field values. Syntax db.collection.find({"outerObject.arrayField.nestedObject.fieldName": value}) Sample Data db.demo687.insertMany([ { CountryName: 'US', info: { id: 101, details: [ ...
Read MoreHow to query MongoDB similar to "like" ?
To implement similar to "like" functionality in MongoDB, use regular expressions with the find() method. MongoDB supports regex patterns using the /pattern/flags syntax to perform case-sensitive and case-insensitive searches. Syntax db.collection.find({ fieldName: /pattern/flags }); // Common patterns: db.collection.find({ fieldName: /searchText/i }); // Case-insensitive db.collection.find({ fieldName: /^searchText/ }); // Starts with db.collection.find({ fieldName: /searchText$/ }); // Ends with db.collection.find({ fieldName: /searchText/ }); // Contains (case-sensitive) Sample ...
Read MoreMongoDB aggregation to fetch documents with specific field value?
To fetch documents with a specific field value using MongoDB aggregation, use the aggregate() method with the $match stage to filter documents based on field criteria. Syntax db.collection.aggregate([ { $unwind: "$arrayField" }, { $match: { "arrayField.fieldName": value } }, { $project: { _id: 0 } } ]); Sample Data db.demo685.insertOne({ "details": [ { "Name": "Chris", ...
Read MoreHow do I sort natural in MongoDB?
Use $natural to sort documents in MongoDB by their natural order (the order they were inserted into the database). This operator sorts documents based on their physical storage order on disk. Syntax db.collection.find().sort({ $natural: 1 }) // Ascending (insertion order) db.collection.find().sort({ $natural: -1 }) // Descending (reverse insertion order) Sample Data Let us create a collection with documents ? db.demo684.insertMany([ {Value: 10}, {Value: 50}, {Value: 60}, {Value: 40} ]); ...
Read MoreWhat happens when we try to add a number to undefined value?
If you try to add a number to an undefined value, you will get NaN (Not a Number). This happens because JavaScript cannot perform mathematical operations when one operand is undefined. Understanding NaN NaN stands for "Not a Number" and is returned when a mathematical operation cannot produce a meaningful numeric result. When you add a number to undefined, JavaScript attempts type coercion but fails, resulting in NaN. Case 1: Direct Addition with Undefined Here's what happens when you directly add a number to undefined ? var result = 10 + undefined; console.log(result); console.log(typeof ...
Read MoreCount the documents with a field value beginning with 13
To count documents where a field value begins with "13", use MongoDB's $regex operator with the ^ anchor for pattern matching, combined with the count() method for efficient counting. Syntax db.collection.count({ "fieldName": { "$regex": "^13" } }); Sample Data db.demo570.insertMany([ {Information: {Value: "13675"}}, {Information: {Value: "14135"}}, {Information: {Value: "15113"}}, {Information: {Value: "13141"}} ]); { "acknowledged": true, "insertedIds": [ ...
Read MoreMongoDB query to match documents whose _id is in an array as part of a subdocument?
To match documents whose _id is in an array stored as part of a subdocument, use the $in operator combined with distinct() to extract array values from the subdocument field. Syntax db.targetCollection.find({ "_id": { "$in": db.sourceCollection.distinct("arrayField.subField", {filter}) } }); Sample Data Create a collection with an array of subdocuments containing IDs ? db.demo568.insertOne({ _id: 101, details: [ { id: 101 }, ...
Read MoreMongoDB collection query to exclude some fields in find()?
To exclude specific fields from MongoDB query results, set the unwanted fields to 0 in the projection parameter of the find() method. This allows you to retrieve documents while hiding sensitive or unnecessary data. Syntax db.collectionName.find( { query }, { fieldToExclude1: 0, fieldToExclude2: 0 } ); Sample Data db.demo567.insertMany([ { "Name": "Chris", "Age": 21 }, { "Name": "David", "Age": 23 }, { "Name": "Bob", "Age": 22 }, { "Name": ...
Read MoreGrouping the array items in MongoDB and get the count the products with similar price?
To group array items in MongoDB and count products with similar prices, use the $unwind operator to flatten the array, then $group by price and $sum to count occurrences. Syntax db.collection.aggregate([ { $unwind: "$arrayField" }, { $group: { "_id": "$arrayField.fieldToGroupBy", "count": { $sum: 1 } }}, { $sort: { "_id": 1 } } ]) Sample Data db.products.insertOne({ ...
Read More