Session 1

Question 1

What is Big Data?

Answer 1

Big Data is large, complex data that’s hard to process with traditional tools.

Example: Healthcare records

Question 2

Difference between structured and unstructured data

Answer 2

Structured data is organised and stored in fixed formats like databases (e.g., Excel spreadsheets), while unstructured data lacks a predefined format, such as emails, videos, or social media posts.

Question 3

What does RDBMS stand for?

Answer 3

Relational Database Management System

Question 4

What is RDBMS?

Answer 4

It is the basis for SQL, and for all modern database systems. The data in RSBMS is stored in database objects called tables. A table is a collection of related data entries and it consists of columns and rows.

Question 5

Command for deleting an existing SQL Database

Answer 5

DROP TABLE ‘insert table name’

Question 6

Command for creating a new database

Answer 6

CREATE DATABASE ‘insert name’

Question 7

NULL VALUE VS NOT NULL

Answer 7

NULL means no value is assigned (unknown or missing).

NOT NULL means a value must always be provided (it cannot be left empty).

Question 8

Creating a table

Answer 8

Use project name;
CREATE TABLE table_name (
column1 datatype,
column2 datatype,
column3 datatype,
);

Question 9

DATA TYPES: CHAR(size)

Answer 9

Fixed length text. The size defines the exact number of characters it will store.

For example CHAR(5) means it can store up to 5 characters. Even if only “hi” is input it will be stored as “hi “ (three spaces totalling to 5 characters).

Question 10

DATA TYPES: VARCHAR(size)

Answer 10

Stores variable-length text.

The size defines the maximum number of characters it can store, but unlike CHAR, it only uses the exact space needed for the input without adding extra padding.

For example, VARCHAR(5) can store up to 5 characters. If you insert “Hi,” it will store just “Hi” (no extra spaces).

Question 11

DATA TYPES: BINARY

Answer 11

Fixed length strings, where size is the number of binary characters to store.

The size defines the exact number of bytes it stores.

Question 12

DATA TYPES: FLOAT(p)

Answer 12

Floating point number. Where p is a precision

It’s used to store approximate numerical values with a precision p, which determines the number of significant digits. The precision affects how the value is stored and calculated.

If p is 1 to 24, the value is stored as a single-precision (4 bytes).

If p is 25 to 53, it is stored as double-precision (8 bytes).

For example, FLOAT(10) will store a number with up to 10 significant digits.

Question 13

DATA TYPES: INTEGER

Answer 13

Standard integer value, allows whole numbers. INTEGER stores whole numbers (no decimals) from -2 billion to 2 billion.

Question 14

DATA TYPES: DECIMAL (m,d)

Answer 14

Fixed point number, where m is the total digits and d is the number of digits after the decimal.

For example, DECIMAL(5, 2) can store numbers like 123.45 (5 digits total, 2 after the decimal).

Question 15

DATA TYPES: BOOLEAN

Answer 15

BOOLEAN stores true or false values, often represented as 1 (true) and 0 (false).

Question 16

DATA TYPES: DATE

Answer 16

Displayed as ‘YYY-MM-DD’

Question 17

DATA TYPES: TIME

Answer 17

Displayed as ‘HH:MM:SS’

Question 18

DATA TYPES: TIMESTAMP

Answer 18

Displayed as ‘YYY-MM-DD HH:MM:SS’

Question 19

What datatype to enter when creating table for id

Answer 19

INT

Question 20

What datatype to enter when creating table for name/text

Answer 20

VARCHAR(n)

Question 21

What datatype to enter when creating table for whole numbers

Answer 21

INTEGER

Question 22

How to populate inside several tables

Answer 22

INSERT INTO table_name (column1_name, column2_name, column3_name) VALUES

(‘Data’, ‘Data’, ‘Data’),
(‘Data’, ‘Data’, ‘Data’),
(‘Data’, ‘Data’, ‘Data’),
(‘Data’, ‘Data’, ‘Data’);