SQL, databases and ORMs

Question 1

1NF (First Normal Form) Rules

Answer 1

1NF (First Normal Form) Rules

• Each table cell should contain a single value.
• Each record needs to be unique.

Question 2

2NF (Second Normal Form) Rules

Answer 2

2NF (Second Normal Form) Rules

• Rule 1- Be in 1NF
• Rule 2- Single Column Primary Key that does not functionally depend on any subset of candidate key relation

Question 3

3NF (Third Normal Form) Rules

Answer 3

3NF (Third Normal Form) Rules
- Rule 1- Be in 2NF
- Rule 2- Has no transitive functional dependencies
(when changing a non-key column, might cause any of the other non-key columns to change)

Question 4

2 types of databases

Answer 4

Relational - SQL

Non Relational - NoSQL

Question 5

Design of all the tables and the relationships is called…

Answer 5

a schema

Question 6

Main unique id is called…

Answer 6

primary key

Question 7

Link to a unique id in another table is called…

Answer 7

foreign key

Question 8

Relationship types:

Answer 8

one to one
one to many
many to many

Question 9

What is a migration?

Answer 9

It’s a record keeping track of a series of changes to a database (that can be ‘played back’ to reproduce changes on the database)

Question 10

What is an ORM?

Answer 10

Object Relational Mapper - maps javascript object to database table