Databases and SQL

Question 1

What is a database?

Answer 1

A database is a container for data storage.

Databases are controlled by a database management system.

Question 2

What are the database types?

Answer 2

Relational, object oriented and NoSQL.

Question 3

What are the steps of good database design?

Answer 3

1. Purpose
2. Organize information
3. Divide into tables
4. Information to columns
5. Specify primary keys
6. Set up relationships
7. Refine
8. Normalize

Question 4

What is ERD?

Answer 4

ERD stands for Entity Relationship Diagram; it is a visual starting point for database design.

Question 5

What is SQL?

Answer 5

SQL stands for Structured Query Language

Question 6

Name some common SQL queries

Answer 6

SELECT - get data 
INSERT - add new row 
DELETE - remove row 
UPDATE - update row 
WHERE - filter by conditions 
LIKE - if value starts or ends with or contains a specific value 
ORDER BY - sort by column 
GROUP BY - group by column in case of duplicates 
DISTINCT - get unique values by column