I need all value in some of my columns to be alphanumeric with a length between 2 and 9. Some of these columns need to nullable while others should not be.
These columns are currently varchar(9).
Should I create a user defined data type for it and alter those columns. Or should I use LEN(Column) > 1 check constraints instead?
Can I define the nullability of these columns when altering them to a user defined data type or do I need to define nullabilty for it when creating the data type.
These tables have more write traffic to them than read traffic, is there a performance difference between the check constraint and the user defined data type?