Create Model Objects and Save to Database

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The Rails console is an interactive tool for running Ruby code that is able to access our app’s model code (among other things). We will use it to explore the kinds of things we can do with our model in Ruby on Rails. The Ruby code we will write in the console is the same sort of code we might write, for example, in our app’s controller methods to enable our app to perform various functions.

Task

• Create new model objects and save them to the database using two approaches.
  • Approach 1: Use the create method.
  • Approach 2: Use the new constructor and save method.

Steps: Create New Object Using create

Launch Rails console:

rails console

Create new Person object and save to database via create:

Person.create(first_name: 'Homer', last_name: 'Simpson', height_inches: 60, weight_lbs: 241)

• SQL INSERT command creates new row in people table.

Exit Rails console:

exit

Inspect people table:

psql --command="SELECT * FROM people" app_development

• “Homer” row now added.
• ⚠️ Press Q key to quit if command locks terminal.

Steps: Create New Object Using new/save

Launch Rails console:

rails console

Create new (unsaved) Person object via new:

marge = Person.new

• Returns Person object (#<Person:0x000000010702cf08), but no SQL commands run.

Set object’s attribute values:

marge.first_name = "Marge"
marge.last_name = "Simpson"
marge.height_inches = 102
marge.weight_lbs = 139

Save object to database:

marge.save

• SQL INSERT command creates new row in people table..

Exit Rails console:

exit

Inspect people table:

psql --command="SELECT * FROM people" app_development

• “Marge” row now added.
• ⚠️ Press Q key to quit if command locks terminal.

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