ActiveRecord :: ConnectionNotEstablished Ruby on Rails入门

Question

I am absolutely new to Ruby on Rails and I'm following a book that's written as a tutorial, but it is a bit outdated.

When I run the server and browse localhost:3000 something is not working right, I get the following error: ActiveRecord::ConnectionNotEstablished

MySQL is installed in my computer, the databases are created and all of this works in other example applications I have been giving a look to.

This is the databases.yml file:

development:
  adapter: mysql2
  database: emporium_development
  username: emporium
  password: hacked

test:
  adapter: mysql2
  database: emporium_test
  username: emporium
  password: hacked

I made sure the mysql2 gem is installed like this: gem install mysql2

Shed some light on me please.

Answer 1

First setup your gems by running

Bundle install

Then your database needs to be created:

rake db:create

If you have some pending migrations (and if you don't this can still be run, it just won't do anything):

rake db:migrate

This should setup a database that works, provided you gave the correct password.

Note that if you already have a database that you want to get rid of, you can run

rake db:drop

and then try to create the database again.

Does any of this solve your problem ?