[sakai2-tcc] [Building Sakai] The myth of schemas (was: Assignments...)

[David Adams]

Steve Swinsburg wrote:
> You may not have got the gist of my earlier comments, but I was
> agreeing with you.

I did get that, but I think a lot of the poor technical decisions in
the Sakai community going back to CHEF days and continuing most
spectacularly into the OAE project is wrapped up in this idea that
relational databases are a hinderance to be gotten around however
possible. Your comments reinforced that false idea, and I think
it's important to address them to avoid the continued unquestioned
acceptance of that idea within this community.

I called your claims poisonous because the idea that there's some
magic easy path to deal with data storage, sorting, searching, and
collating is very tempting, and every time someone claims that
"technology X *never* has problem Y that relational databases
suffer from", there are a hundred readers out there who take that to
heart. But it's not true. The problems are the same, no matter what
storage mechanism you use. If they manifest in slightly different
ways, that may be a fact you can use to your advantage depending on
your system design, but schema changes are part of every system.

For any non-trivial data, there is a schema implicit in both the data
and the code. And for any non-trivial system, schema transitions will
be required. I would argue that non-trivial schema transitions can be
*much* harder on non-RDBMS systems. We only have to look at all the
work expended in the OAE project on its own schema changes for evidence.

-dave