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MongoDB Articles
Page 90 of 111
How to convert from string to date data type in MongoDB?
To convert from string to date data type in MongoDB, you can use the ISODate() function within a script that iterates through documents and updates them. This is useful when you have date fields stored as strings that need to be converted to proper date objects. Syntax db.collection.find().forEach(function(doc){ doc.dateField = ISODate(doc.dateField); db.collection.save(doc); }); Create Sample Data Let us first create a collection with documents containing string date values ? db.stringToDateDataTypeDemo.insertMany([ {"CustomerName": "Carol", "ShippingDate": "2019-01-21"}, {"CustomerName": "Bob", ...
Read MoreFind inside a hash MongoDB?
To find inside a hash (embedded document) in MongoDB, use dot notation to access nested fields. This allows you to query specific fields within embedded documents using the format "parentField.childField". Syntax db.collection.find({ "embeddedDocument.field": "value" }); Sample Data Let us create a collection with documents containing embedded ClientDetails ? db.hashDemo.insertMany([ { "ClientName": "Larry", "ClientAge": 23, "ClientDetails": { ...
Read MoreQuery MongoDB for a datetime value less than NOW?
To query MongoDB for datetime values less than the current time, use the $lte operator with new Date() which returns the current timestamp. Syntax db.collection.find({ "dateField": { $lte: new Date() } }); Sample Data db.dateTimeValueLessThanNowDemo.insertMany([ { "CustomerName": "Larry", "CustomerProductName": "Product-1", "ArrivalDate": new ISODate("2017-01-31") }, { ...
Read MoreAdding new property to each document in a large MongoDB collection?
To add a new property to each document in a large MongoDB collection, use the forEach() method combined with update() and $set operator. This approach iterates through all documents and adds the new field dynamically. Syntax db.collection.find().forEach(function(doc) { db.collection.update( {_id: doc._id}, {$set: {newProperty: computedValue}} ); }); Create Sample Data db.addingNewPropertyDemo.insertMany([ {"StudentName": "John", "StudentAge": 23, "CountryName": "US"}, {"StudentName": "David", "StudentAge": 21, "CountryName": ...
Read MoreHow to terminate a MongoDB shell script earlier?
To terminate a MongoDB shell script earlier, you can use the quit() or quit(1) command. This immediately exits the MongoDB shell and returns control to the operating system command prompt. Syntax quit() quit(1) Where quit() exits with status code 0 (success), and quit(1) exits with status code 1 (error). Sample Data Let us first create a collection with sample documents to demonstrate the quit functionality ? db.flightInformation.insertMany([ {"FlightName": "Flight-1", "ArrivalTime": new ISODate("2019-03-12")}, {"FlightName": "Flight-2", "ArrivalTime": new ISODate("2019-03-31")} ]); { ...
Read MoreRenaming column name in a MongoDB collection?
To rename a field (column) name in a MongoDB collection, use the $rename operator. This operator allows you to change field names across multiple documents in a single operation. Syntax db.collectionName.updateMany( {}, { $rename: { "oldFieldName": "newFieldName" } } ); Sample Data Let us create a collection with sample documents ? db.renamingColumnNameDemo.insertMany([ { "StudentName": "Larry", "Age": 23 }, { "StudentName": "Sam", "Age": 26 }, { "StudentName": "Robert", "Age": 27 } ]); ...
Read MoreHow to store query result (a single document) into a variable?
To store a query result (a single document) into a variable in MongoDB, use the var keyword with find().limit(1) to retrieve only one document. You can then access the stored result by referencing the variable name. Syntax var variableName = db.collectionName.find().limit(1); variableName; // Display the stored result Sample Data Let us first create a collection with sample documents ? db.storeQueryResultDemo.insertMany([ {"ClientName": "Chris", "ClientAge": 23}, {"ClientName": "Robert", "ClientAge": 21}, {"ClientName": "Sam", "ClientAge": 25}, {"ClientName": "Mike", "ClientAge": 26} ...
Read MoreHow to find two random documents in a MongoDB collection of 6?
To find two random documents from a MongoDB collection, use the $sample aggregation stage. This operator randomly selects a specified number of documents from the collection efficiently. Syntax db.collection.aggregate([ { $sample: { size: NumberOfDocuments } } ]); Sample Data Let us create a collection with 6 student documents ? db.twoRandomDocumentDemo.insertMany([ {"StudentId": 10}, {"StudentId": 100}, {"StudentId": 45}, {"StudentId": 55}, {"StudentId": 5}, {"StudentId": 7} ]); ...
Read MoreHow to check if field is a number in MongoDB?
To check if a field is a number in MongoDB, use the $type operator with the value "number". This operator matches documents where the specified field contains numeric values (integers, doubles, or decimals). Syntax db.collectionName.find({fieldName: {$type: "number"}}); Sample Data Let us create a collection with documents containing different data types ? db.checkIfFieldIsNumberDemo.insertMany([ {"StudentName": "John", "StudentAge": 23}, {"StudentName": "Chris", "StudentMathScore": 98, "StudentCountryName": "US"}, {"StudentName": "Robert", "StudentCountryName": "AUS"}, {"StudentId": 101, "StudentName": "Larry", "StudentCountryName": "AUS"} ]); ...
Read MoreBuilding Multiple Indexes at once in MongoDB?
To build multiple indexes at once in MongoDB, use the createIndexes() method and pass multiple index specifications in an array. This approach is more efficient than creating indexes one by one. Syntax db.collection.createIndexes([ { "field1": 1 }, { "field2": -1 }, { "field3": 1, "field4": 1 } ]); Example Let's create multiple single-field indexes on a collection ? db.multipleIndexesDemo.createIndexes([ {"First": 1}, {"Second": 1}, {"Third": 1}, ...
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