On Jun 20, 8:44 pm, MeBuggyYouJane <gnuo...@rcn.com> wrote:
> Serge Rielau wrote:
> > Well, I suppose we both made our points.
> > One thing is disturbing to me though:
> > What the heck is your issue with Don? I learned SQL from Don :-)
>
> Which, of course, got me motivated to review the history of IMS/CODASYL,
> and to this quote from Stonebraker/Hellerstein:
>
> Unfortunately, the main proposal in the current XML era bears a striking
> resemblance to the CODASYL proposal from the early 1970's, which failed
> because of its complexity. Hence, the current era is replaying history,
> and "what goes around comes around". Hopefully the next era will be
> smarter.
>
> It comes up in a Google search as Chapter 1 from an MIT Press text.
> This contradicts my recollection to the extent: 1) IMS post-dated
> CODASYL, 2) IMS was created because IBM wanted out of a "standard"
> database they couldn't lock in (call me paranoid, but that was widely
> believed at the time), and 3) XML is IMS in drag, not CODASYL, aka
> Network Database.
>
> I feel much better now. The lithium is kicking in.

To say that CODASYL databases are complex is an understatement. I
recall working in an IDMS shop, and production schema changes were
only allowed once every 6 months. In devlelopment, schema changes were
allowed once per month. When a schema change was made, every COBOL
program that touched the database had to be recompiled.

IMS as program product "may" have post-dated CODASYL, but its origin
was really an IBM application development project for NASA which
needed a database, so they wrote their own for that project. Project
deadlines, etc of a application development projects have their own
considerations that are different than someone designing a product
from the ground up to be sold in the marketplace. Sure, IBM could have
come up with a "pure" CODASYL database, but a bird in the hand is
worth two in the bush.

DB2 had its origins in a research lab, although the final DB2 product
contained some compromises from the pure relational research effort.