30+ AARKFAB ENGINEERS Interview Questions and Answers

Constraints faced in Data Validation with illustrations

• 1. Format constraints: Ensuring data follows a specific format (e.g. date in MM/DD/YYYY format)

• 2. Range constraints: Validating data falls within a specified range (e.g. age between 18-65)

• 3. Mandatory constraints: Ensuring required fields are not empty (e.g. email address field)

• 4. Consistency constraints: Checking data consistency across multiple fields (e.g. start date before end date)

• 5. Uniqueness constraints: Verifying...read more

Different validations in testing include input validation, boundary validation, error handling validation, and data validation.

• Input validation ensures that the system accepts only valid inputs.

• Boundary validation checks the system's behavior at the boundaries of valid input ranges.

• Error handling validation verifies that the system handles errors gracefully.

• Data validation ensures that the data processed by the system is accurate and consistent.

SQL query to find duplicate values in a scenario

• Use the GROUP BY clause to group the values

• Use the HAVING clause to filter out groups with count greater than 1

• Select the columns with duplicate values

The candidate is asked to write the outputs for all joins from a given scenario.

• Inner join: Returns rows when there is a match in both tables

• Left join: Returns all rows from the left table and the matched rows from the right table

• Right join: Returns all rows from the right table and the matched rows from the left table

• Full outer join: Returns all rows when there is a match in either table

Use SQL query with GROUP BY and HAVING clause to delete duplicate values

• Use GROUP BY clause to group the records based on the columns that should not have duplicates

• Use HAVING clause to filter out the groups that have more than one record

• Use DELETE statement to remove the duplicate records

Use IS NULL or = '' to find NULL or BLANK values in SQL

• Use IS NULL to find NULL values in a column

• Use = '' to find BLANK values in a column

• Example: SELECT * FROM table_name WHERE column_name IS NULL OR column_name = ''

Set operators are used in SQL to perform operations on sets of data, such as union, intersect, and except.

• Union - combines the results of two or more SELECT statements, removing duplicates

• Intersect - returns the common rows between two SELECT statements

• Except - returns the rows that are in the first SELECT statement but not in the second SELECT statement

Agile ceremonies are regular meetings or events in Agile methodology to facilitate communication and collaboration within the team.

• Sprint Planning: Plan the work to be done in the upcoming sprint.

• Daily Standup: Daily meeting to discuss progress, challenges, and plans for the day.

• Sprint Review: Demo of completed work to stakeholders for feedback.

• Sprint Retrospective: Reflect on the sprint and identify areas for improvement.

• Backlog Refinement: Review and prioritize items in the...read more

Transactional data refers to real-time data related to business transactions, while Master Data is the core data that is essential to operations.

• Transactional data is dynamic and changes frequently, such as sales orders, invoices, and payments.

• Master Data is static and remains unchanged over time, such as customer information, product details, and employee records.

DELETE removes specific rows from a table, DROP removes entire table, TRUNCATE removes all rows from a table.

• DELETE is a DML command used to remove specific rows from a table based on a condition.

• DROP is a DDL command used to remove an entire table along with its structure and data.

• TRUNCATE is a DDL command used to remove all rows from a table but keeps the table structure intact.

• DELETE is slower than TRUNCATE and DROP as it maintains logs for rollback.

• DROP is faster than DEL...read more

Developed a test automation framework using Selenium for web application testing

• Created test scripts in Java to automate regression testing

• Integrated with Jenkins for continuous integration

• Used Page Object Model design pattern for better code maintenance

Test Improvement Process is a systematic approach to enhancing the efficiency and effectiveness of software testing.

• Identifying areas of improvement in the testing process

• Implementing changes to address the identified issues

• Measuring the impact of the changes on testing outcomes

• Continuously iterating and refining the testing process

• Examples: introducing automation, improving test coverage, enhancing test data management

CRUD stands for Create, Read, Update, Delete - the four basic functions of persistent storage.

• Create - testing the ability to create new resources through API calls

• Read - testing the ability to retrieve existing resources from the API

• Update - testing the ability to modify existing resources through API calls

• Delete - testing the ability to remove resources from the API

SQL queries are executed in a specific order to ensure accurate results.

• SQL query is parsed to check syntax errors

• Query optimizer creates an execution plan

• Data is retrieved from tables based on the execution plan

• Filters and joins are applied to the retrieved data

• Aggregations and sorting are performed on the data

• Results are returned to the user

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Normalization involves breaking down data into smaller, more manageable parts.

• It helps in reducing data redundancy by storing data in a structured manner.

• Normalization ensures data integrity by avoiding anomalies like insertion, update, and deletion anomalies.

• There are different normal forms like 1NF, 2NF, 3NF, BCNF, etc.

• For example, in a database table, instead of st...read more

Referential integrity is a database concept that ensures relationships between tables are maintained.

• It ensures that foreign key values in one table match primary key values in another table.

• It prevents orphaned records by enforcing constraints on relationships.

• It helps maintain data consistency and accuracy.

• Example: If a customer places an order, the customer ID in the orders table must exist in the customers table.

Data acquisition is the process of collecting and measuring information from various sources for analysis and storage.

• Involves capturing data from sensors, instruments, or other devices

• Can include sampling, digitizing, and processing data

• Common in fields like scientific research, industrial automation, and environmental monitoring

OLAP is used for analyzing and reporting complex data, while OLTP is used for transaction processing.

• OLAP stands for Online Analytical Processing, used for data analysis and reporting.

• OLTP stands for Online Transaction Processing, used for transactional operations.

• OLAP deals with historical data and is read-heavy, while OLTP deals with current data and is write-heavy.

• OLAP databases are optimized for complex queries and aggregations, while OLTP databases are optimized for fast...read more

DDL, DML, DCL, and TCL are different types of SQL commands used for database management.

• DDL (Data Definition Language) is used to define the structure of database objects like tables, indexes, etc. Examples: CREATE, ALTER, DROP.

• DML (Data Manipulation Language) is used to manipulate data in the database. Examples: INSERT, UPDATE, DELETE.

• DCL (Data Control Language) is used to control access to data in the database. Examples: GRANT, REVOKE.

• TCL (Transaction Control Language) is u...read more

ETL stands for Extract, Transform, Load while ELT stands for Extract, Load, Transform.

• ETL involves extracting data from source systems, transforming it, and then loading it into a data warehouse or data lake.

• ELT involves extracting data from source systems, loading it into a data lake or data warehouse, and then transforming it as needed.

• ETL is suitable for structured data while ELT is suitable for unstructured data.

• ETL requires a separate transformation engine while ELT leve...read more

Windows Functions are built-in functions in SQL Server that perform operations on a set of rows and return a single aggregated value.

• Used for performing calculations on a set of rows in a table

• Commonly used functions include SUM, AVG, COUNT, MIN, MAX

• Can be used with GROUP BY clause to group results based on a specific column

• Example: SELECT SUM(sales) FROM sales_table WHERE year = 2021

Defect Life Cycle is the process of identifying, reporting, fixing, retesting, and closing software defects.

• Defect Identification: Defects are identified through testing or user feedback.

• Defect Reporting: Defects are reported in a defect tracking tool with details like steps to reproduce, severity, and priority.

• Defect Fixing: Developers fix the reported defects based on the information provided.

• Defect Retesting: Testers verify that the fixed defects are indeed resolved.

• Defect...read more

Identify the issue, isolate the code, fix the issue, test the fix, and deploy the updated code.

• Identify the issue by reviewing logs and error messages.

• Isolate the code by identifying the specific module or function causing the issue.

• Fix the issue by updating the code and testing the fix.

• Test the fix by running automated and manual tests to ensure the issue is resolved.

• Deploy the updated code to the appropriate environment.

Codd's rules are a set of 12 rules proposed by Edgar F. Codd to define what is required from a database management system to be considered relational.

• Codd's rules were created to ensure that a database management system is truly relational.

• Some of the key rules include the rule of data independence, rule of guaranteed access, and rule of comprehensive data sub-language.

• An example of a Codd's rule is the rule of view updating, which states that all views that are theoretically...read more

To select a regression candidate, I consider factors like criticality, impact, and frequency of use. I prepare reports on test coverage, defects, and regression results. As a test manager, I prioritize and coordinate the resolution of production bugs.

• Consider criticality, impact, and frequency of use when selecting a regression candidate

• Prepare reports on test coverage, defects, and regression results

• Prioritize and coordinate the resolution of production bugs as a test manage...read more

A test plan is created by defining objectives, scope, resources, schedule, and approach for testing.

• Define objectives and scope of testing

• Identify resources needed for testing

• Establish a schedule for testing activities

• Outline the approach and methodologies for testing

• Include risk assessment and mitigation strategies

• Document test scenarios, test cases, and test data

• Define roles and responsibilities of team members

Middleware in .NET Core is a pipeline of components that handle HTTP requests and responses.

• Middleware components can be added to the pipeline using the Use() method in the Startup class.

• Middleware can be used for authentication, logging, routing, and more.

• Middleware can be created using classes or lambda expressions.

• Middleware can be ordered in the pipeline using the Order property.

• Examples of middleware include AuthenticationMiddleware, RoutingMiddleware, and StaticFileMidd...read more

Code optimization techniques aim to improve the efficiency and speed of code execution.

• Use efficient algorithms and data structures

• Minimize memory usage and avoid unnecessary operations

• Use compiler optimizations and profiling tools

• Consider parallelization and concurrency

• Avoid premature optimization and focus on bottleneck areas

Lifecycle hooks are methods that allow you to tap into the lifecycle of a component or directive in Angular.

• There are eight different lifecycle hooks available in Angular.

• They are: ngOnChanges, ngOnInit, ngDoCheck, ngAfterContentInit, ngAfterContentChecked, ngAfterViewInit, ngAfterViewChecked, ngOnDestroy.

• Each hook is called at a specific point in the component or directive's lifecycle.

• For example, ngOnInit is called after the component has been initialized and ngOnChanges is...read more

Data traversal in MVC involves accessing and manipulating data within the model layer of the MVC architecture.

• Data traversal is the process of accessing and manipulating data within the model layer of the MVC architecture

• This can be done using various techniques such as LINQ, foreach loops, and lambda expressions

• Data traversal is important for retrieving and displaying data to the user in the view layer of the MVC architecture

MVC life cycle involves request processing, controller execution, view rendering, and response generation.

• The request is received by the front controller

• The front controller selects the appropriate controller

• The controller processes the request and returns a model

• The view is rendered using the model data

• The response is generated and sent back to the client