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To sort field values in MongoDB, use the sort() method with field name and sort direction. Use 1 for ascending order and -1 for descending order. Syntax db.collection.find().sort({ "fieldName": 1 }); // Ascending db.collection.find().sort({ "fieldName": -1 }); // Descending Sample Data db.demo365.insertMany([ { "FirstName": "Chris" }, { "FirstName": "Adam" }, { "FirstName": "John" }, { "FirstName": "Bob" } ]); { "acknowledged": true, "insertedIds": [ ... Read More
To find MongoDB records containing field names with dots, use the aggregation pipeline with $addFields, $objectToArray, and $filter operators. The $indexOfBytes operator detects dot characters in field names. Syntax db.collection.aggregate([ { $addFields: { result: { $filter: { ... Read More
To fetch multiple documents in MongoDB using OR condition, use the $or operator which performs a logical OR operation on an array of expressions and selects documents that satisfy at least one of the expressions. Syntax db.collection.find({ $or: [ { field1: value1 }, { field2: value2 }, { field3: value3 } ] }); Sample Data db.demo362.insertMany([ { ... Read More
To use an object field as a key for finding values in MongoDB, use dot notation to access nested object properties in the projection parameter of the find() method. Syntax db.collection.find({}, {"objectName.fieldName": 1}); Sample Data Let us create a collection with nested object documents − db.demo361.insertMany([ {"details": {"FirstName": "Chris", "LastName": "Brown"}}, {"details": {"FirstName": "David", "LastName": "Miller"}}, {"details": {"FirstName": "John", "LastName": "Doe"}} ]); { "acknowledged": true, "insertedIds": [ ... Read More
To get the current and previous documents in MongoDB, use sort() with limit() to retrieve the most recent documents based on a specific criteria. This approach helps you find the latest two records that match your query conditions. Syntax db.collection.find( { field: { $lte: value } }, { projection } ).sort({ _id: -1 }).limit(2); Sample Data Let us create a collection with sample documents: db.demo360.insertMany([ { id: 101, "Name": "Chris" }, { id: 102, "Name": "David" ... Read More
To concatenate values of an array with other fields in MongoDB, use $reduce to convert the array into a single string, then $concat to combine it with other fields in the $project stage. Syntax db.collection.aggregate([ { $project: { arrayAsString: { $reduce: { ... Read More
Yes, the $match operator works perfectly in MongoDB aggregation queries. It filters documents in the aggregation pipeline, similar to the find() method's query criteria, but as the first stage of data processing. Syntax db.collection.aggregate([ { $match: { "field": "value" } }, // Additional pipeline stages... ]); Sample Data db.demo358.insertMany([ { "ClientId": 101, "ClientName": "Chris", "ClientAge": 34 }, { "ClientId": 102, "ClientName": "David", "ClientAge": 32 }, { "ClientId": 103, "ClientName": "David", "ClientAge": 35 }, ... Read More
To fetch a specific document from MongoDB where a field value is set using NumberInt(), use dot notation to target nested fields and match the exact NumberInt() value in your query. Syntax db.collection.find({"field.nestedField": NumberInt(value)}); Sample Data Let us create a collection with documents containing NumberInt() values − db.demo357.insertMany([ { "FirstName": "Chris", "Age": 21, "details": { ... Read More
MongoDB provides built-in document validation to enforce data quality rules before inserting or updating documents. Use the validator option during collection creation to define validation criteria using MongoDB query operators. Syntax db.createCollection("collectionName", { validator: { $jsonSchema: { /* validation rules */ } // OR /* MongoDB query expression */ }, validationLevel: "strict", // or "moderate" validationAction: "error" ... Read More
To project specific elements in an array field in MongoDB, use the $project stage with $filter to conditionally include array elements that match your criteria. Syntax db.collection.aggregate([ { $project: { arrayField: { $filter: { input: "$arrayField", ... Read More