Rangoli House Interview Questions and Answers

To get non-repeated entries from a table, use the DISTINCT keyword in SQL.

• Use SELECT DISTINCT column_name FROM table_name

• DISTINCT keyword returns only unique values

• Can be used with multiple columns

• Can also use GROUP BY clause

Multi-threading and multi-tasking are techniques used to improve the performance of a computer system.

• Multi-threading is the ability of a CPU to run multiple threads of execution concurrently.

• Multi-tasking is the ability of an operating system to run multiple applications or processes concurrently.

• Multi-threading is used to improve the performance of a single application by dividing it into smaller threads that can run concurrently.

• Multi-tasking is used to improve the overall...read more

Primary key uniquely identifies a record in a table, while a unique key ensures that all values in a column are distinct.

• Primary key is a column or set of columns that uniquely identifies each row in a table

• Primary key cannot have null values

• A table can have only one primary key

• Unique key is a column or set of columns that ensures that all values in the column(s) are distinct

• Unique key can have null values, but only one null value is allowed

• A table can have multiple unique ke...read more

Oops features are object-oriented programming concepts that help in creating reusable and modular code.

• Encapsulation - bundling data and methods that operate on that data within a single unit

• Inheritance - creating new classes from existing ones, inheriting their properties and methods

• Polymorphism - ability of objects to take on multiple forms or behaviors

• Abstraction - hiding implementation details and showing only the necessary information

A primary key is a unique identifier for a record in a database table.

• Primary key ensures that each record in a table is unique

• It is used to establish relationships between tables

• It cannot contain null values

• Examples include social security numbers, email addresses, and employee IDs

A virtual function is a function in a base class that is declared using the keyword 'virtual' and can be overridden by a function with the same signature in a derived class.

• Virtual functions allow for dynamic polymorphism in object-oriented programming.

• They are used to achieve runtime polymorphism by allowing a function to be overridden in a derived class.

• Virtual functions are declared in the base class with the 'virtual' keyword and can be overridden in derived classes using...read more