Following the WordPress idea of creating a file for development and its minified version is very good and you should have both files in your plugin, and based on this variable you will enqueue one or the other.
Activates the Logs
Check that the values must be bool instead of string
WordPress default files wp-includes and wp-admin will be set to its development version if set to true.
To remove this feature all around you can set this constant to false.
When you are dealing with the database you might want to save your queries so that you can debug what is happening inside of your plugin or theme.