Enforce Data Integrity With Check Constraints

I came across some code the other day that simply horrified me. I was looking at a table that had a field name which implied it stored a boolean value (e.g. IS_LAUGHABLE). The field type is defined as a char(1), allows NULL values and defined no default value. Looking at the data in the column I found a combination of the following values: T, F, Y, and N. Read more