ModelsDatabasesRelationships.md

Models, Databases, Relationships in Rails

What is the difference between a primary key and a foreign key? Where would we find a primary key? What would it be called by default? Where would we find a foreign key? What is the naming convention for a foreign key?

• Primary key determines uniqueness of an entry in a table (generally, but not necessarily "id")
• Foreign key references an entry in another table (by its primary key) ("foreignTableName_id")

Write down one example of:

• Spouses/Couples, Person-SSN,
• House-Occupants, School-Students
• Albums-Artists, Students-Classes, Video Games-Players

What's the difference between test, development, and production databases?

• Test is for running your test suite, generally wiped during each test2
• Development is for interacting during development
• Production is for the live data from the real world

How do you create a Rails app from the command line with a postgres database

• rails new appname -d postgresql

What files are created by typing rails g model ...?

• A migration
• A model
• A model test
• Fixtures