title: I have StartDate and EndDate for each record. Should I give NULL a special meaning when used in these 2 fields?
body: <p>So, I have a table where StartDate and EndDate's are used to determine the activeness of a record. I thought of using NULLs to relieve the maintainers from having to manufacture some crazy dates for some of the records. For example, if NULL had defined as positive infinite when used in EndDate, the data maintainers wouldn't need to come up with something like 1-1-2100 for long-lived records. </p>
  
  <p>I can speculate some of the trade offs on my own: defining NULL as infinities means cleaner data and elimination of periodic maintenance work, but it also means longer queries and stored procedures. So I was wondering how you guys in the real world weigh in on this. </p>
  
  <p>EDIT: the opinions are about half-half. If I had clarified that the StartDate and EndDate are used solely for the purpose of determining the activeness of a record in the where clause, and never appears in the select list, would that tilt the scale? One subject I need to read on is probably indexing. Thanks'all. </p>