Thoughts on manual database design?
mhs.stein at gmail.com
Fri Oct 2 17:36:29 CDT 2015
I'm just surprised that it looks like the
names/descriptions are the key; what if you
repaint the BLUE cabinet in your wife MARY'S
BEDROOM red, or for that matter if you remarry and
MARY'S BEDROOM becomes LINDA'S BEDROOM?
Does the software update all occurrences
automatically, or am I misunderstanding?
----- Original Message -----
From: "Jay Jaeger" <cube1 at charter.net>
To: <cctalk at classiccmp.org>
Sent: Friday, October 02, 2015 5:06 PM
Subject: Re: Thoughts on manual database design?
> There are three columns named Location for a
> There is the column Location in a table all by
> itself. That is a list
> of locations - not just for manuals, but,
> eventually, for all of my
> Then there is a table of Cabinets. Each Cabinet
> has a single location
> at any given time. But Cabinet by itself may
> not be unique, so Location
> comes along for the ride as part of the key for
> the table of cabinets.
> Manual artifacts (copies) are stored in
> Cabinets. Yes, I *could* have
> created a separate key for each Cabinet, and
> stored that in the Manual
> table and the Cabinet table (like I did to
> relate Manuals to the other
> tables), but that would have actually
> complicated the design, so instead
> I used the same concatenation which is the key
> to the Cabinet table.
> The database is defined such that Location is a
> foreign key in Cabinet,
> and the keys to Cabinet (tee hee) are a foreign
> key in Manual_Artifact.
> This allows the database to *guarantee* that
> there is not any Manual
> whose Cabinet does not exist or a Cabinet whose
> Location does not exist.
> It also allows the web applications to easily
> populate pull down lists
> without having to read through the entire
> artifacts table. With a
> database this small that probably doesn't matter
> much, but if the table
> had millions of rows it certainly would.
> Type and manufacturer are handled the same way
> for the same reason.
> I could have made a more relationally pure
> design by creating a separate
> table of Artifacts and Cabinets, Cabinets and
> Locations and so on. But
> because each of those relationships is just one
> to many and never many
> to many, there was no point in my mind (purists
> would probably
> disagree). Not so for manuals and machines -
> many manuals may apply to
> a given machine, and a given manual may apply to
> many machines, so that
> had relation to be stored in a separate table.
> Historial digression....
> I have been doing database design essentially
> like this from *before*
> relational databases were well known and
> commercially available, at
> Wisconsin DOT, which developed its own database
> system called File
> Handler in the early 1970's, starting on an IBM
> 360/65 MP with 2MB of
> core. It was written because the other DBMS's
> at the time were either
> too slow, to big or required taking too much of
> the database too often
> for reorganizations. (IBM's IMS, in
> particular). DB2 did not yet
> exist. Huge gamble management took on the
> programmers that wrote it,
> which paid off in millions of dollars saved in
> computer capacity alone.
> For a while, for performance reasons, we had a
> "cheat" that could store
> a one to many relation in a single column (which
> we called a "repeating
> group") that was done for our drivers database.
> We broke them out into
> separate tables when we upgraded to an Amdahl
> 470/V6 in 1976.
> File Handler production before I started there
> in 1975, I was the
> primary DBA for it for about 7 years before I
> moved on to other things.
> It had features like row-level blank
> compression, elimination of nulls
> at the column level (a bitmap indicated which
> columns were present), an
> API which had a LALR compiler which parsed
> queries (though for online
> production we required them to be pre-compiled),
> full (single phase)
> commit with preempt detection including
> redundant log and checkpoint
> files in case the machine went down mid-commit
> and so on. It used
> techniques for indexing that would be
> recognizable today. It was almost
> its own OS: by the time we were done it had (in
> order of development)
> its own memory management ("KORMAN" aka
> "Harvey"), task management and
> program loading/content management ("CONMAN").
> It supported the SMP
> fully, though applications were usually written
> to be single-threaded in
> a given serially-reusable application instance -
> though you could have
> multiple instances of the same application
> running. A man named Robert
> Tomlinson wrote the query compiler, and used
> some of his work on File
> Handler for his advanced degree theses (at least
> his PhD, for certain).
> I was an EE student at the same time he was at
> U. Wisconsin, though our
> paths never crossed.
> Florida DOT acquired the code from us in the
> late 1970's, and
> established it, with some assistance from
> Wisconsin DOT staff, as their
> motor vehicle and/or driver database system for
> many years as well. I
> have a copy of that instance of the code, and
> have run the thing under
> Hercules, just for giggles. Wisconsin DOT
> retired the last vestige of
> it just last year - it had a 40 year run, all
> On 10/2/2015 1:38 PM, Mike Stein wrote:
>> Is that the way it's done these days, e.g. the
>> contents of the Location
>> field in three places, Location and Manual_Type
>> only containing one
>> field, no keys other than Manual_Key etc.?
>> Looks like I'll have to brush up on database
>> design... ;-)
>> ----- Original Message ----- From: "Jay Jaeger"
>> <cube1 at charter.net>
>> To: <cctalk at classiccmp.org>
>> Sent: Friday, October 02, 2015 11:59 AM
>> Subject: Re: Thoughts on manual database
>>> On 10/2/2015 12:04 AM, william degnan wrote:
>>>> Coming up with a schema that works with
>>>> multiple manufacturers is the
>>> Not sure it is that big a challenge.
>>> Perfection is not required. Just
>>> the ability to find stuff later. My schema
>>> currently has manual
>>> manufacturer - the original manufacturer of
>>> the machine, and then each
>>> artifact (copy of a manual) has a publisher.
>>> Consider the case of Apollo which got bought
>>> by HP.
>>> For a DNxxxx machine, the machine manufacturer
>>> is always Apollo. For a
>>> 400 or 700 series, the manufacturer is always
>>> HP. However a given copy
>>> of a manual may have been published by Apollo
>>> (older) or HP (newer) -
>>> with the very same number. The schema
>>> supports that.
>>> (New schema posted at
>>> ) .
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