pindell-matt · April 5, 2016 18:46
diff --git a/ModelsDatabasesRelationships.md b/ModelsDatabasesRelationships.md
 ## Models, Databases, Relationships in Rails

 #### What is the difference between a primary key and a foreign key? 
 Primary Keys are uniq_ids for a table, foreign keys are primary keys featured on a separate table.

 #### Where would we find a primary key? 
 On any table.

 #### What would it be called by default? 
 Id.

 #### Where would we find a foreign key? 
 On a Join Table

 #### What is the naming convention for a foreign key?
 tablename_id

 #### Write down one example of:
 * a `one-to-one `relationship: Person-to-Fingerprint
 * a `one-to-many relationship`: Bag-to-Cheetos
 * a `many-to-many relationship`: People-to-Cheetos

 #### What's the difference between test, development, and production databases?
 They are separate databases, containing different data, for each environment (test, development, and production)

 #### How do you create a Rails app form the command line with a postgres database?
 rails new appname -d postgresql
 rails new appname --database=postgresql

 #### What files are greated by typing `rails g model ...`?
 The model.rb file, the model_test.rb, a fixture to provide the model_test fake data, and the migration.rb file.

 #### What's the difference between typing `rails g model ...` and `rails g migration ...`?
 model generates 4 files, model / model_test / fixture / migration file.
 migration generates only the migration file.

 #### Imagine that the items table has a category called quantity. What command would you type if you wanted to get rid of the quantity attribute?
 rails g migration RemoveQuantityFromItems quantity:integer
	## Models, Databases, Relationships in Rails

	#### What is the difference between a primary key and a foreign key?
	Primary Keys are uniq_ids for a table, foreign keys are primary keys featured on a separate table.

	#### Where would we find a primary key?
	On any table.

	#### What would it be called by default?
	Id.

	#### Where would we find a foreign key?
	On a Join Table

	#### What is the naming convention for a foreign key?
	tablename_id

	#### Write down one example of:
	* a `one-to-one `relationship: Person-to-Fingerprint
	* a `one-to-many relationship`: Bag-to-Cheetos
	* a `many-to-many relationship`: People-to-Cheetos

	#### What's the difference between test, development, and production databases?
	They are separate databases, containing different data, for each environment (test, development, and production)

	#### How do you create a Rails app form the command line with a postgres database?
	rails new appname -d postgresql
	rails new appname --database=postgresql

	#### What files are greated by typing `rails g model ...`?
	The model.rb file, the model_test.rb, a fixture to provide the model_test fake data, and the migration.rb file.

	#### What's the difference between typing `rails g model ...` and `rails g migration ...`?
	model generates 4 files, model / model_test / fixture / migration file.
	migration generates only the migration file.

	#### Imagine that the items table has a category called quantity. What command would you type if you wanted to get rid of the quantity attribute?
	rails g migration RemoveQuantityFromItems quantity:integer