Synechron Interview Questions, Process, and Tips

Types of joins in SQL are Inner Join, Left Join, Right Join, and Full Join.

• 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 Join: Returns rows when there is a match in one of the tables.

GROUP BY is used to group rows that have the same values into summary rows, while HAVING is used to filter groups based on a specified condition.

• GROUP BY is used with aggregate functions to group the result set by one or more columns.

• HAVING is used to filter groups based on a specified condition after the GROUP BY clause.

• GROUP BY is used before the HAVING clause in a query.

• Example: SELECT department, COUNT(*) FROM empl

DML commands are Data Manipulation Language commands used to manage data in a database.

• DML commands include INSERT, UPDATE, DELETE, and SELECT.

• INSERT is used to add new rows of data into a table.

• UPDATE is used to modify existing data in a table.

• DELETE is used to remove rows of data from a table.

• SELECT is used to retrieve data from a database.

Primary key uniquely identifies each record in a table, while Unique key allows only one instance of a value in a column.

• Primary key does not allow NULL values, while Unique key allows one NULL value.

• Primary key automatically creates a clustered index, while Unique key creates a non-clustered index by default.

• Primary key can be referenced by foreign keys, while Unique key cannot be referenced by foreign keys.

Indexes are data structures that improve the speed of data retrieval operations in a database.

• Indexes are used to quickly locate data without having to search every row in a database table.

• Types of indexes include clustered, non-clustered, unique, and composite indexes.

• Clustered indexes determine the physical order of data in a table, while non-clustered indexes store a separate copy of the indexed columns.

• Unique index...read more

Execution plan is a roadmap that SQL Server uses to execute a query, showing the steps taken to retrieve data.

• Execution plan is generated by the query optimizer to determine the most efficient way to execute a query.

• It shows the order in which tables are accessed, joins are performed, and filters are applied.

• Execution plan can be viewed using tools like SQL Server Management Studio or by using the EXPLAIN statement in

SQL query to retrieve the maximum salary for each department

• Use the MAX() function to find the maximum salary

• Group the results by department using the GROUP BY clause

• Join the employee table with the department table to get the department information

Different types of SQL joins with given data sets a and b.

• Inner join: Returns rows where there is a match in both tables (1,1)

• Left join: Returns all rows from the left table and the matched rows from the right table (1,1,1,2,2)

• Right join: Returns all rows from the right table and the matched rows from the left table (1,1,2,4)

• Cross join: Returns the Cartesian product of the two tables (1,1,1,1,1,2,1,4,1,1,2,1,2,2,1,4,2,...read more

row_number, rank, dense_rank are window functions in SQL used to assign a unique number to each row based on specified criteria.

• row_number() assigns a unique sequential integer starting from 1 to each row in the result set

• rank() assigns a unique rank to each row based on the specified ordering criteria, with gaps in ranking for ties

• dense_rank() assigns a unique rank to each row based on the specified ordering criteria,

A trigger is a special type of stored procedure that automatically executes when certain events occur in a database.

• Triggers can be used to enforce business rules, maintain referential integrity, and automate repetitive tasks.

• Examples of trigger events include INSERT, UPDATE, and DELETE operations on a table.

• Triggers can be defined to execute before or after the triggering event.

Functions return a value, while stored procedures do not. Functions can be used in SELECT statements, stored procedures cannot.

• Functions return a single value, while stored procedures can return multiple values or none at all.

• Functions can be used in SELECT statements to return a value, while stored procedures cannot be used in this way.

• Functions can be called from within stored procedures, but stored procedures cannot

Different ways to inject services in .NET

• Constructor Injection: Services are injected through a class constructor

• Property Injection: Services are injected through public properties

• Method Injection: Services are injected as method parameters

• Service Locator Pattern: Services are accessed through a central registry

• DI Containers: Frameworks like Autofac, Unity, or Ninject manage service injection

JWT authentication in Web API involves generating a token with user credentials and validating it on subsequent requests.

• JWT stands for JSON Web Token, which is a compact and self-contained way for securely transmitting information between parties as a JSON object.

• In Web API, a JWT token is generated upon successful authentication and is sent to the client.

• The client includes the JWT token in the Authorization header o...read more

Custom middleware in .NET allows for custom logic to be executed before or after an HTTP request is processed.

• Create a class that implements the IMiddleware interface

• Override the InvokeAsync method to add custom logic

• Register the middleware in the Startup class using the UseMiddleware extension method

MVC is a design pattern used in .NET development, while .NET lifecycle refers to the stages of a .NET application's execution.

• MVC is a design pattern that separates an application into three main components: Model, View, and Controller.

• .NET lifecycle refers to the stages of a .NET application's execution, including initialization, execution, and termination.

• MVC helps in achieving separation of concerns and making the c...read more

Dispose is used to release unmanaged resources immediately, while Finalize is used for cleanup operations before an object is destroyed by the garbage collector.

• Dispose is called explicitly by the developer, while Finalize is called by the garbage collector.

• Dispose should be implemented in classes that directly interact with unmanaged resources.

• Finalize should be implemented in classes that need to release resources be...read more

DOM sanitizer in Angular is used to sanitize untrusted HTML to prevent XSS attacks.

• DOM sanitizer is used to sanitize HTML content before rendering it in Angular templates.

• It helps prevent Cross-Site Scripting (XSS) attacks by removing potentially harmful content.

• Angular provides a built-in DomSanitizer service for sanitizing HTML content.

• Example: Using DomSanitizer in Angular template to sanitize a URL before rendering

I use Ngrx for state management in my current project by defining actions, reducers, effects, and selectors.

• Define actions to describe user events or interactions

• Create reducers to specify how state should change in response to actions

• Implement effects to manage side effects like API calls

• Use selectors to retrieve specific pieces of state for components

Stored procedures are precompiled SQL queries stored in the database, while functions are reusable code blocks that return a value.

• Stored procedures are used for performing specific tasks or operations on the database.

• Functions are used to encapsulate logic and can be called within SQL queries or other functions.

• Stored procedures can have input and output parameters, while functions always return a value.

• Stored procedu...read more

Model binder in MVC is used to map data from HTTP requests to action method parameters in controllers.

• Model binder maps form data, query string parameters, and route data to action method parameters in MVC controllers.

• It helps in simplifying the process of extracting data from HTTP requests.

• Model binder can be customized by creating custom model binders to handle complex data binding scenarios.

Yes, the transaction will be rolled back if the innermost stored procedure throws an error.

• If an error occurs in the innermost stored procedure, it will cause the entire transaction to be rolled back.

• This ensures that the database remains in a consistent state.

• Rolling back the transaction means that any changes made by the stored procedures within the transaction will be undone.

NgOnInit is a lifecycle hook in Angular that is called after the component has been initialized, while the constructor is a TypeScript feature used to initialize class properties.

• NgOnInit is specific to Angular components, while constructor is a general TypeScript feature.

• NgOnInit is used for initialization logic that relies on Angular's view and input bindings being initialized, while constructor is used for basic ini...read more

zone.js is a library for managing asynchronous operations in Angular applications.

• zone.js helps in tracking asynchronous operations and their execution context in Angular applications.

• It provides hooks for intercepting asynchronous tasks like setTimeout, setInterval, and promises.

• zone.js can be used for profiling, debugging, and error handling in Angular applications.

Use a query with GROUP BY and HAVING clause to identify and remove duplicates from a table.

• Use GROUP BY to group rows with the same values

• Use HAVING COUNT(*) > 1 to identify duplicates

• Use DELETE statement to remove duplicates