TCS iON System Engineer Interview Questions, Process, and Tips

Primary key uniquely identifies a record in a table while foreign key refers to a field in another table.

• Primary key is used to enforce data integrity and ensure uniqueness of records.

• Foreign key is used to establish a relationship between two tables.

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

• Primary key cannot have null values while foreign key can have null values.

• Example: In a database of studen...read more

Arrays and lists are data structures used to store multiple values in a single variable.

• Arrays are fixed in size and can hold values of the same data type.

• Lists are dynamic in size and can hold values of different data types.

• Arrays and lists are indexed starting from 0.

• Arrays and lists are commonly used in programming for storing and manipulating data.

• Example of an array: ['apple', 'banana', 'orange']

• Example of a list: