MySQL No database selected rails - mysql

Question

I got something like this when i hit rake db:migrate
Im using figaro in my app, its my first time with this gem any mysql so I cant get what excatly is wrong.
Thanks in advance :)
Mysql2::Error: No database selected: CREATE TABLE schema_migrations (version varchar(255) PRIMARY KEY) ENGINE=InnoDB
database.yml
default: &default
adapter: mysql2
encoding: utf8
pool: 5
username: <%= ENV["DB_USER"] %>
password: <%= ENV["DB_PASSWORD"] %>
development:
<<: *default
database: <%= ENV["DB_DATABASE_DEV"] %>
test:
<<: *default
database: <%= ENV["DB_DATABSE_TEST"] %>
production:
<<: *default
database: <%= ENV['DB_DATABASE_PRODUCTION'] %>
application.yml
default: &default
adapter: mysql2
encoding: utf8
pool: 5
username: root
password: password
development:
<<: *default
database: dev
test:
<<: *default
database: test_db

Answer 1

I don't have enough point to ask in comment, but it seems you're trying to run migration without creating a schema first.
Run rails db:create to create the schema first. For example, if you don't have the a database named "dev" in your MySQL, this command will do so.
rails db:create
To set specific environment
rails db:create RAILS_ENV=test
Then you run canrails db:migrate.
To destroy a schema if you need one:
rails db:drop
You're Using ENV
Though it might not be related, have you set up your ENV properly before running the command?
For Windows, you can add those, for example, DB_USER to system environment
Just press Start and type system environment >> Environment Variables... >> New...
Variable Name: DB_USER
Variable Value: your_username
Note: You might have to restart your system for the environment to work.
Or if you don't have time, simply in your terminal you're running rails s:
C:\Sites\ProjectName> set DB_USER=your_username
C:\Sites\ProjectName> set DB_PASSWORD=your_username
C:\Sites\ProjectName> rails s
The same steps for Linux, but I don't know the specific command. Some prefer to use .env file.

Answer 2

I've run into this trouble a couple days ago, and it's very annoying because Rails tried to create dev and test db's when in dev environment. Nothing worked.
I ended up hard-coding database: into database.yml, and let Figaro manage credentials.

Answer 3

I runned the same issue today.
Ensure you have dotenv-rails gem installed and that "DB_DATABASE_DEV" has a value in your .env file.
Also, make sure your database has been created.

Answer 4

It happens when your database.yml does not include database: some_database part or when database name is empty. In your case you can use one of few options:
Option 1: run migrations with database name env variable included
DB_DATABASE_DEV=your_dev_db_name rails db:<task>
Option 2: use hard-coded db name in your database.yml file
# database.yml
development:
<<: *default
database: my_development_database
Option 3: make sure that env variables are correctly loaded
To do so in linux, simply write in terminal:
echo ${DB_DATABASE_DEV}
On windows terminal you need to write this:
echo %DB_DATABASE_DEV%
If you get no content then this env variable is not set