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Articles by Smita Kapse
Page 16 of 39
How can I rename a field for all documents in MongoDB?
To rename a field for all documents in MongoDB, use the $rename operator with an empty query filter to match all documents. This operation updates the field name across the entire collection. Syntax db.collectionName.updateMany( {}, { $rename: { "oldFieldName": "newFieldName" } } ); Sample Data Let's create a collection with student documents ? db.renameFieldDemo.insertMany([ { "StudentName": "John" }, { "StudentName": "Carol" }, { "StudentName": "Bob" }, { "StudentName": ...
Read MoreHow to create MongoDB stored procedure?
MongoDB allows you to create stored procedures (server-side JavaScript functions) using the db.system.js collection. These functions are stored on the server and can be called using db.eval(). Syntax db.system.js.save({ _id: "yourStoredProcedueName", value: function(argument1, argument2, ...argumentN) { // function body return result; } }); Example: Create Addition Function Let's create a stored procedure that adds two numbers ? db.system.js.save({ _id: "addTwoValue", ...
Read MoreCheck if a field contains a string in MongoDB?
You can use the $regex operator to check if a field contains a string in MongoDB. This allows pattern matching and substring searches within document fields. Syntax db.collection.find({ "fieldName": { $regex: ".*searchString.*" } }); Sample Data db.checkFieldContainsStringDemo.insertMany([ { "Id": 1, "Name": "John" }, { "Id": 2, "Name": "Johnson" }, { "Id": 3, "Name": "Carol" }, { "Id": 4, "Name": "Mike" }, { "Id": 5, "Name": "Sam" }, { "Id": ...
Read MoreHow to copy a collection from one database to another in MongoDB?
In MongoDB, there is no built-in command to copy a collection from one database to another. To achieve this, use the find().forEach() method combined with getSiblingDB() to iterate through documents and insert them into the destination database. Syntax db.collectionName.find().forEach(function(doc){ db.getSiblingDB('destinationDatabase')['collectionName'].insert(doc); }); Create Sample Data First, let's create a collection in the test database with some documents ? use test; db.userCollection.insertMany([ {"User_Id": 101, "UserName": "Larry"}, {"User_Id": 102, "UserName": "Maxwell"}, {"User_Id": 103, "UserName": "Robert"} ]); ...
Read MoreHow to perform ascending order sort in MongoDB?
To sort documents in ascending order in MongoDB, use the sort() method with a field value of 1. This arranges documents from lowest to highest based on the specified field. Syntax db.collectionName.find().sort({fieldName: 1}); Sample Data Let us create a collection with sample documents to demonstrate sorting ? db.sortingDemo.insertMany([ {"Value": 100}, {"Value": 1}, {"Value": 150}, {"Value": 250}, {"Value": 5}, {"Value": 199}, {"Value": 243}, ...
Read MoreFind MongoDB records where array field is not empty?
To find MongoDB records where an array field is not empty, use the $ne (not equal) operator with an empty array []. You can also combine it with $exists to ensure the field exists and is not empty. Syntax db.collection.find({ "arrayField": { $exists: true, $ne: [] } }); Sample Data db.arrayFieldIsNotEmptyDemo.insertMany([ {"StudentName": "Larry", "StudentTechnicalSubject": ["Java", "C"]}, {"StudentName": "Mike", "StudentTechnicalSubject": []}, {"StudentName": "Sam", "StudentTechnicalSubject": ["MongoDB"]}, {"StudentName": "Carol", "StudentTechnicalSubject": []}, {"StudentName": ...
Read MoreHow to replace substring in MongoDB document?
In MongoDB, you can replace substrings in documents using JavaScript's replace() function within a forEach() loop. This approach finds documents, modifies the substring, and updates them back to the collection. Sample Data db.replaceSubstringDemo.insertOne({ "WebsiteURL": "www.gogle.com" }); { "acknowledged": true, "insertedId": ObjectId("5c76eaf21e9c5dd6f1f78276") } Let's verify the document was inserted ? db.replaceSubstringDemo.find().pretty(); { "_id": ObjectId("5c76eaf21e9c5dd6f1f78276"), "WebsiteURL": "www.gogle.com" } Replace Substring Using forEach() To replace "gogle" with ...
Read More"Toggle" query in MongoDB?
To implement a toggle query in MongoDB, you need to find the document first and then use the update operation to toggle the boolean field value. The toggle operation switches a boolean value from true to false or vice versa. Let us first create a collection with sample documents − > db.toggleDemo.insertOne({"CustomerName":"John Smith", "CustomerAge":28, "isMarried":true}); { "acknowledged" : true, "insertedId" : ObjectId("5cc7be138f9e6ff3eb0ce43b") } > db.toggleDemo.insertOne({"CustomerName":"David Miller", "CustomerAge":25, "isMarried":false}); { "acknowledged" : true, "insertedId" : ObjectId("5cc7be2e8f9e6ff3eb0ce43c") } Following is the query to display all ...
Read MoreSingle query vs multiple queries to fetch large number of rows in SAP HANA
When dealing with large datasets in SAP HANA, choosing between single query and multiple queries significantly impacts performance. Single query would always be better than the multiple queries. The number of rows does not impact much on performance. It is the way query is written and the data to be fetched which makes the difference. Also, the table should be indexed. Why Single Query Performs Better Single queries outperform multiple queries due to several key factors − Reduced network overhead ...
Read MoreDetermining table or structure of an ABAP code
In ABAP, you can define variables as either tables (internal tables) or structures using different syntax approaches. Understanding the distinction between these two data types is crucial for effective ABAP programming. Defining Internal Tables To define an internal table, you use the TABLE OF keyword. This creates a table where each line has the structure of the specified type − DATA: abc TYPE TABLE OF PPP. In this declaration, abc would be an internal table and its line will be of type PPP. Each row in the table will have the structure defined by ...
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