ClaySys .NET Trainer Interview Questions and Answers

Structured Query Language (SQL) is a standard language for managing and manipulating databases.

• SQL is used to communicate with databases to perform tasks like querying data, updating records, and creating tables.

• Common SQL commands include SELECT, INSERT, UPDATE, DELETE, and CREATE.

• SQL is not case-sensitive, but it is conventionally written in uppercase for keywords and lowercase for table and column names.

Primary key uniquely identifies each record in a table, while unique key ensures each value in a column is unique.

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

• A table can have only one primary key, but multiple unique keys.

• Primary key is automatically indexed, while unique key may or may not be indexed.

• Example: Primary key for a 'Students' table could be 'StudentID', while unique key could be 'Email'.

Types of inheritance in .NET include single, multiple, multilevel, hierarchical, and hybrid inheritance.

• Single inheritance: A class can inherit from only one base class.

• Multiple inheritance: A class can inherit from multiple base classes (not supported in C#).

• Multilevel inheritance: A class can inherit from a derived class, creating a hierarchy of classes.

• Hierarchical inheritance: Multiple classes can inherit from a single base class.

• Hybrid inheritance: Combination of multipl...read more

OOPs stands for Object-Oriented Programming. It is a programming paradigm based on the concept of objects.

• OOPs focuses on creating objects that contain data and methods to manipulate that data.

• It involves concepts like inheritance, encapsulation, polymorphism, and abstraction.

• Example: Inheritance allows a class to inherit properties and methods from another class, promoting code reusability.

Inheritance is a mechanism in object-oriented programming where a class inherits properties and behaviors from another class.

• Allows a class to reuse code from another class

• Promotes code reusability and reduces redundancy

• Derived class inherits members from base class

• Example: Class Car can inherit properties and methods from class Vehicle