from msdn for SQL Server, http://msdn.microsoft.com/en-us/library/ms998577.aspx in reference to Figure 14.2. Now the query shown is a poorly written query, but the article claims that with a foreign key, the query optimizer can optimize (read: correct) the query. I can see the scenario happening with some auto generated queries...
Foreign keys in production offer safety, safety, safety. If incoming data were ALWAYS clean (3rd party data feeds) or that a DBA never had to make an ad hoc update to production to satisfy something ultra business critical, then perhaps Foreign keys are just for development, but until then, I root safety.
Foreign keys in production offer safety, safety, safety. If incoming data were ALWAYS clean (3rd party data feeds) or that a DBA never had to make an ad hoc update to production to satisfy something ultra business critical, then perhaps Foreign keys are just for development, but until then, I root safety.