On Apr 24, 2006, at 16:31, Jim Zajkowski wrote:
the database schema under a version control system.
I enjoy selective quoting as much as everyone else, but you should
have included the paragraph above it:
Yeah, that was a reply to a reply where I tried to be brief, I quoted
the rest in the real reply.
Because migrations are stepwise pieces that can be checked into a
SCM like Subversion.
Note the word “stepwise.” You do not get update steps with a
simply checked-in schema.sql file.
You can get that using version control revisions. If you check out
revision 54 you get back to the schema as it was in 54. And most of
the times you want to go back in the application as well, because it
is rare that schema in revision 54 works nicely with an application
in revision 73 using an schema from revision 70.
Note that I wasn’t claiming maintenance is comparable. I claimed
that the fact that “stepwise” evolution of schemas is easier is
orthogonal to the fact that the team or several computers can stay in
sync with that data, we did that before migrations.
But the real point is that I was greatly simplifying why you would
want to use migrations for someone who wanted to know why he should
look into them. I was not posting someone you to come along and
pick apart single phrases because it wasn’t 100% correct, or
correct in all cases. Your argument is like someone complaining
that the teacher isn’t using the full relativity forumlas when
teaching newtonian physics to a bunch of highschool students.
Please don’t take it personally, I am very sorry if you did. That was
not my intention!
I just wanted to clarify a point in that mail where I thought
confusion could arise, that’s standard in technical forums. I mean,
if I write something false, inaccurate, or that needs some additional
comment (in my view that particular point of that reply falls in the
last case), I want people to prove me wrong, to correct or improve
the mail, because the only thing that matters to me is the OP,
readers, and the archives.
Please excuse me again.
PS: You mentioned physics, I happen to have background in math, where
truth and correctness is above individuals generally speaking,
correcting arguments and being corrected is very normal and expected.