$lookup (aggregation) $lookup is thus a stage in the MongoDB aggregation pipeline. $Lookup is used to perform a left outer join between two collections in a MongoDB database. A left outer join combines all the documents or entries on the left with matching documents or entries on the right. Syntax:
MongoDB supports logical query operators. These operators are used for filtering the data and getting precise results based on the given conditions. The following table contains the comparison query operators: Matching values using $and operator: In this example, we are retrieving only those employee’s documents whose status is ACTIVE
MongoDB uses various comparison query operators to compare the values of the documents. The following table contains the comparison query operators: Matching values using $nin operator: In this example, we are retrieving only those employee’s documents whose name is not Daisy or Amruta. //Example db.q_employee.find({name:
Create a new Spring Boot project using start.spring.io 1. Open your browser and navigate to the https://start.spring.io. 2. From the “Project” dropdown, select “Gradle — Kotlin”. 3. Choose “Kotlin” as the language. 4. In the “SpringBoot” section, input the desired Spring Boot version — in this case,
CQRS (Command Query Responsibility Segregation) is a design pattern that suggests separating read and write operations into separate models to improve scalability, performance, and maintainability of the system. In a microservices architecture, CQRS can be applied to separate the command side (write operations) from the query side (read operations) of
What is a variable? A variable is a storage for a value, which can be a string, a number, or something else. Every variable has a name (or an identifier) to distinguish it from other variables. You can access a value by the name of the variable. Declaring variables Before
What is Kotlin? Kotlin is a highly effective modern programming language developed by JetBrains. It has a very clear and concise syntax, which makes your code easy to read. Kotlin is widely used around the world, and its popularity among developers is constantly growing. A sample Kotlin function Here is
We will be using OpenJDK 17. Downloads → OpenJDK: Download and install Install Instructions: Mac: You can install sdkman (Home - SDKMAN! the Software Development Kit Manager ) which can manage multiple installations of java. Also can be used to manage gradle versions. sdk install java 17.0.0-open * Please follow the
In this post, we’ll introduce you to formatting Kotlin code with ktlint, and specifically focus on adding ktlint to your Kotlin project. Why use ktlint? In some cases, ktlint can even reformat your code for you when there is an issue. This allows developers to focus their time and
What is Software Testing : Verifying application support customer business or not. What is Automation Testing : Testing perform by using automation tool. What is Automation Tool : It is software which is use to test another software. Selenium Tool : It is automation testing tool which is use to perform functionality testing on
It is developer tool used by development team to perform unit testing, It is java base application. Tester will use TestNG for automating test script. Advantages of TestNG : 1)It provides parallel execution of test method. 2)Auto execution report generation. 3)TestNG allows grouping of test methods into test
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