SQL Server bit column constraint, 1 row = 1, all others 0

Question

I have a bit IsDefault column. Only one row of data within the table may have this bit column set to 1, all the others must be 0.

Answer 1

The accepted answer to the below question is both interesting and relevant:

Constraint for only one record marked as default

"But the serious relational folks will tell you this information should just be in another table."

Have a separate 1 row table that tells you which record is 'default'. Anon touched on this in his comment.

I think this is the best approach - simple, clean & doesn't require a 'clever' esoteric solution prone to errors or later misunderstanding. You can even drop the IsDefualt column.