database.yml is the database configuration file. It contains the required information for rails to connect to your database.

By default it contains three configurations: production, development, and test.

The data is formated in [[YAML]], so watch for tabs, as they are significant.

h3. How do I fix `No such file or directory - /tmp/mysql.sock` ?

Check that the socket exists, and if not, check your mysql configuration. Next make sure your database config file(database.yml) points to the correct file.

<pre><code>socket: /path/to/mysql.sock</code></pre>

for example, under Gentoo, the socket is likely at <code>/var/run/mysqld/mysqld.sock</code>. Try <code>locate mysqld.sock</code> if you're not sure where yours is.

If you'd rather use TCP/IP sockets instead of Unix sockets, change the server directive to "127.0.0.1" instead of "localhost".