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Database Articles
Page 66 of 547
MongoDB query to search date records using only Month and Day
To search MongoDB documents using only month and day while ignoring the year, use the $where operator with JavaScript functions like getMonth() and getDate(). Syntax db.collection.find({ $where: function() { return this.dateField.getMonth() == monthValue && this.dateField.getDate() == dayValue; } }); Sample Data db.demo181.insertMany([ {"ShippingDate": new ISODate("2020-01-10")}, {"ShippingDate": new ISODate("2019-12-11")}, {"ShippingDate": ...
Read MoreHow to find latest entries in array over all MongoDB documents?
To find latest entries in array over all MongoDB documents, use the aggregate() method with $unwind to flatten arrays, $sort to order by the desired field, and $limit to get the top entries. Syntax db.collection.aggregate([ { "$unwind": "$arrayField" }, { "$sort": { "arrayField.sortField": -1 } }, { "$limit": numberOfEntries } ]); Sample Data db.demo179.insertMany([ { "Name": "Chris", "Details": [ ...
Read MoreMongoDB query to fetch date records (ISODate format) in a range
To fetch date records within a specific range from MongoDB documents containing ISODate format dates, use range operators like $gte, $lte, $gt, and $lt in your queries, or aggregation pipeline operators for more complex date filtering. Syntax // Basic date range query db.collection.find({ "dateField": { "$gte": ISODate("start_date"), "$lte": ISODate("end_date") } }); // Aggregation with time-based filtering db.collection.aggregate([ { "$redact": { ...
Read MoreMongoDB query to add a document in an already created collection
To add a document to an existing collection in MongoDB, use the $push operator. This operator appends new documents to an existing array field within a document. Syntax db.collection.update( { "field": "value" }, { $push: { "arrayField": { newDocument } } } ); Sample Data Let's create a collection with sample documents ? db.demo177.insertOne({ "Id": "101", "details": [ { "StudentName": "Chris", ...
Read MoreGet substring in MongoDB aggregate
To extract substring in MongoDB aggregation pipelines, use the $substr operator within the $project stage. This operator extracts a portion of a string starting from a specified position and length. Syntax db.collection.aggregate([ { $project: { fieldName: { $substr: ["$sourceField", startIndex, length] } } } ]) Sample Data db.demo176.insertMany([ {"ProductName": "PRODUCT-1"}, ...
Read MoreHow do I use MongoDB to count only collections that match two fields?
To count documents in MongoDB that match multiple field conditions, use the count() method with a query document containing all required field−value pairs. MongoDB will return the count of documents where all specified conditions are satisfied. Syntax db.collection.count({ "field1": "value1", "field2": "value2" }); Sample Data db.demo175.insertMany([ {"EmployeeName": "Bob", "isMarried": "YES"}, {"EmployeeName": "David", "isMarried": "NO"}, {"EmployeeName": "Mike", "isMarried": "YES"}, {"EmployeeName": "Sam", "isMarried": "NO"} ]); { ...
Read MoreEvaluate one of more values from a MongoDB collection with documents
To evaluate one or more values from a MongoDB collection, use the $or operator with the find() method. The $or operator performs a logical OR operation on an array of expressions and returns documents that match at least one of the conditions. Syntax db.collection.find({ $or: [ { "field1": "value1" }, { "field2": "value2" }, { "fieldN": "valueN" } ] }); Sample Data ...
Read MoreFind a value in lowercase from a MongoDB collection with documents
To find a value in lowercase from a MongoDB collection, use the toLowerCase() method in JavaScript when constructing your query. This allows you to search for documents where a field matches a specific value in lowercase format. Syntax db.collection.find({"fieldName": "VALUE".toLowerCase()}); Sample Data Let us create a collection with documents containing subject names in different cases ? db.demo172.insertMany([ {"SubjectName": "MySQL"}, {"SubjectName": "mongodb"}, {"SubjectName": "MongoDB"} ]); { "acknowledged": true, "insertedIds": [ ...
Read MoreHow to re-map the fields of a MongoDB collection?
To re-map the fields of a MongoDB collection, use $rename operator with update() or updateMany(). This operator allows you to rename field names across documents in your collection. Syntax db.collection.updateMany( {}, { $rename: { "oldFieldName": "newFieldName" } } ); Sample Data Let us create a collection with sample documents ? db.demo171.insertMany([ { "Name": "Chris", "Details": { ...
Read MoreHow to Secure MongoDB on Ubuntu 16.04
In this article, we will learn how to secure MongoDB on Ubuntu 16.04. In previous versions, MongoDB was vulnerable to automated exploits because, by default, there was no authentication required to interact with the database. Any user could create, read, modify and destroy databases and their contents, as the MongoDB daemon listens on all interfaces by default. Enabling Authentication and Adding Admin User This issue has been mitigated in MongoDB versions 3.x and later, however, authentication is still disabled by default. To secure MongoDB, we will create an administrative user and enable authentication. Step 1: Connect to ...
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