Do you know the situations when you would employ an overseas answer to another table instead of make use of a boolean (i.e. BIT in SQL Server)

For instance can you replace the next two booleans within this table:

engine_sensors
--------------
id (int, primary key)
name (varchar(50))
fault_code (int)
display_warning (boolean) /* if fault show driver a warning */
is_test_sensor (boolean) /* ignore this sensor in diagnostic checks */

e.g. display_warning here may not display the warning to some driver but do display an alert to some auto technician who's testing the engine. So another table could be appropriate.

is_test_sensor might be changed by sensor_type (FK to sensor_types table) that has kinds of test,live.

When the fields model a boolean value, I'd leave them as booleans. This is exactly why they exist.

I wouldn't make an effort to future proof my database design (YAGNI principle), you could change it out later on.

This is dependent why you would cure it. You can simply have number fields with for false and 1 for true. Unsure if you will find any benefits though.

You've added one bit of information

'Its is really a SQL Server database and that i realize that you'd use a little area. I'm wondering how bad a concept it's to exchange all of them with foreign secrets to some separate table'

You need to edit your original question and set this in if this sounds like vital that you the answer you seek to ensure that more and more people will have the ability to locate fairly easily it.

However, you still haven't stated why you had been curious about changing all of them with a FK. Should you tell people what your finish goal is or what you're attempting to achieve, they may provide a variety of solutions.

I apologize I can not advise a solution. Is really a foreign key (as to the?) much better than a boolean value? in comparison to ?

I want to explain / re-structure your question a little. Best of luck.