mysql - Could I make a column in a table only allows one 'true' value and all other rows should be 'false'

Question

In MySQL, Can I put a restriction like below at database level?

I need to make sure 1. a specific column can only take either 'true' or 'false' values. 2. and exactly only one row should be having 'true' value?

Answer 1

Rather than having the boolean attribute in the table, you could have another table that contains one row and points to the row in the original table that you consider true.

Changing the true value is a matter of updating the foreign key in the TrueRow table.