First see this:
http://www.loudthinking.com/arc/000516.html
Now, I think Rails’ fixtures violates this. How? Because defaults aren’t
added for columns such as ‘created_at’, etc. (which causes an error if
the field is ‘not null’ and you haven’t specified a created_at value for
your fixtures). Seems like when creating fixtures, the standard Rails
model creation approach should be used.
Joe