Lecture 1

Question 1

What is a database?

Answer 1

Organising data:
- Able to quickly retrieve based on user’s demands
- Can be indexed in many ways
- Has a level of meaning relatable to real world entities
- Can be kept up-to-date and is consistent at all times.

Question 2

Relational Approach

Answer 2

Data is stored in form of relations.

Question 3

Document based approach

Answer 3

Data is stored in the form of documents.

Question 4

When do you need a database?

Answer 4

• When your data no longer fits in memory
• When you need persistence
• If multiple processes need to access and modify the same data
• When you need to secure your data
• When integrity and structure of data is important

Question 5

DBMS

Answer 5

• Can be accessed by multiple users, connect to other systems, etc
• Single point of entry, no redundancy (unless created by users)
• Abstraction trough common interfacing and query language
• Networking
• Separates storage from data
• Manages redundancy and constraints

Job as developer: Abstract the DBMS.
Job as Data scientists: turn data from DBMS into actionable information.

Question 6

SQL

Answer 6

• SQL is a non-procedural language.
• Way to communicate with a DBMS
• The DBMS determines how and when your statement is executed.
• To use databases in your software, you must use an SDK to communicate using SQL with a DBMS.

Question 7

Most common data types in MySQL

Answer 7

• Numeric (int, tinting - boolean, smallint, bigint, decimal, float, real, numeric)
• Date/time
• Character/String
• Unicode character / String
• Binary
• Miscellaneous (BLOB)

BLOB - stores large data, documents, and even media files.

Question 8

SQL

Answer 8

Data types, Create/Alter, Insert, Update, Select, Delete, Drop