Primary Keys

"Amy Blankenship" wrote in
:

"Tim Marshall" wrote in
message ...
Amy Blankenship wrote:

If my Access databases were large enough that indexing were an
issue, they wouldn't be in Access.

OK, I'll leave the church of the not null unique vs. primary key
to you. How many times do you kneel facing Redmond each
day,anyway ;-)?

It is Edgar Codd's legacy to which most of us pay homage, the
platform on which database development takes place is utterly
irrelevant.

I haven't followed this thread, but I have seen this post. No
offence, but you've shown a complete and, if you are anything
close to a "professional" developer, shocking lack of
understanding of relational database design and of "Access" by:

1) Indicating indexing is not an issue; and

2) by referring to "Access databases".

So, you're saying that multiple files created in access are not
Access databases? What do you call them then...?

Just wondering...

We're not talking about Access databases here, but Jet.

D'oh.

--
David W. Fenton http://www.dfenton.com/
usenet at dfenton dot com http://www.dfenton.com/DFA/

See, that right there argues against his point. You couldn't use a date,
for instance, because that might not be unique but you might then want to
use it as a condition in a BETWEEN clause.

"David W. Fenton" wrote in message
. 1...
"Amy Blankenship" wrote in
:

Whoah, whoah. Hang on. I was referring to the topic of this part
of the thread, which was the use of primary keys that are not
unique identifiers of the record in order to cluster them on disk,
NOT simply indexing.

Um, how do you set a non-unique index as a PK? The index has to be
unique to qualify as a PK, however artificially you've created it.

--
David W. Fenton http://www.dfenton.com/
usenet at dfenton dot com http://www.dfenton.com/DFA/

"David W. Fenton" wrote in message
. 1...
"Amy Blankenship" wrote in
:

"Tim Marshall" wrote in
message ...
Amy Blankenship wrote:

If my Access databases were large enough that indexing were an
issue, they wouldn't be in Access.

OK, I'll leave the church of the not null unique vs. primary key
to you. How many times do you kneel facing Redmond each
day,anyway ;-)?

It is Edgar Codd's legacy to which most of us pay homage, the
platform on which database development takes place is utterly
irrelevant.

I haven't followed this thread, but I have seen this post. No
offence, but you've shown a complete and, if you are anything
close to a "professional" developer, shocking lack of
understanding of relational database design and of "Access" by:

1) Indicating indexing is not an issue; and

2) by referring to "Access databases".

So, you're saying that multiple files created in access are not
Access databases? What do you call them then...?

Just wondering...

We're not talking about Access databases here, but Jet.

Now this is just plain silly. The access file is actually a complete
application that contains, among other things, tables that _can be_
accessed by the Jet engine, and are accessed from inside the Access
application (with forms, reports, and module). However, you can also access
the database tables with other engines when calling the *Access Database*
from outside the Access application. In all probability, you could probably
call an Access Database file from another Access Database file using a
different engine, though I have not tried it. It's on my to-do list.

Saying that "Access Database" is not a valid way to refer to a file created
in the Access application containing tables that _can_ be accessed by Jet is
in my opinion a bit of a stretch. However, it does bring up an interesting
question, one I don't claim to know the answer to: if you set up your
indexes from within Access, but then you call the file with another driver,
how do the indexes behave?

-Amy

Amy Blankenship wrote:
"David W. Fenton" wrote in message
. 1...

We're not talking about Access databases here, but Jet.

Now this is just plain silly. The access file is actually a complete
application that contains, among other things, tables that _can be_
accessed by the Jet engine, and are accessed from inside the Access
application (with forms, reports, and module). However, you can also
access the database tables with other engines when calling the
*Access Database* from outside the Access application. In all
probability, you could probably call an Access Database file from
another Access Database file using a different engine, though I have
not tried it. It's on my to-do list.
Saying that "Access Database" is not a valid way to refer to a file
created in the Access application containing tables that _can_ be
accessed by Jet is in my opinion a bit of a stretch. However, it
does bring up an interesting question, one I don't claim to know the
answer to: if you set up your indexes from within Access, but then
you call the file with another driver, how do the indexes behave?

-Amy

I believe David's point is that one can use other programming environments like
VB to create an MDB containing tables along with an entire application to
interface with that MDB all on a PC that does not even have Access installed.
Would you still call that MDB an "Access Database"?

In addition to being able to use a database stored in an MDB file without using
Access one can also build an interface with Access to a non-Jet database like
SQL Server or Oracle. Would you call those "Access Databases"?

Pedantically, when most people talk about an Access Database, the *database* is
a Jet database and the *application* part is Access. I usually use the term
"Access/Jet" if I mean a database application consisting completely of MDB files
and "Access Application" if I am talking about the front end to any other
database engine.

For me the distinction only matters when the discussion concerns "engine level"
stuff. Discussions about keys, constraints, relationships etc., only make sense
when you are specific about whether the engine is Jet or something else.

As for your question, you would be using Access to create Jet indexes so they
would still apply when you interface with the database from another program.


--
Rick Brandt, Microsoft Access MVP
Email (as appropriate) to...
RBrandt at Hunter dot com

"Rick Brandt" wrote

I believe David's point is that one can use
other programming environments like
VB to create an MDB containing tables
along with an entire application to
interface with that MDB all on a PC that
does not even have Access installed.
Would you still call that MDB an
"Access Database"?

Many do, including Microsoft.

Larry

On Sun, 16 Jul 2006 21:19:53 GMT, "Larry Linson" wrote:

"Rick Brandt" wrote

I believe David's point is that one can use
other programming environments like
VB to create an MDB containing tables
along with an entire application to
interface with that MDB all on a PC that
does not even have Access installed.
Would you still call that MDB an
"Access Database"?

Many do, including Microsoft.

Larry

If you create a word document using open office it is still a word document. Or is it?
My god these threads could go on forever!

polite person wrote:

If you create a word document using open office it is still a word document. Or is it?
My god these threads could go on forever!

In the olden days an mdb file was a JET file. If it were created in VB
3's (and others) utility it would not have a reference to Access ...
someone who didn't know about Access might not even guess there was a
close relationship. Since Access objects have been stored in blobs I
don't know whether or not this is still pertinent and I'm not sure
about such things existing any more but my guess is that they do ... or
can. It would be kinda delusionary to call such a file an Access DB?

"Rick Brandt" wrote in message
.com...
Amy Blankenship wrote:
"David W. Fenton" wrote in message
. 1...

We're not talking about Access databases here, but Jet.

Now this is just plain silly. The access file is actually a complete
application that contains, among other things, tables that _can be_
accessed by the Jet engine, and are accessed from inside the Access
application (with forms, reports, and module). However, you can also
access the database tables with other engines when calling the
*Access Database* from outside the Access application. In all
probability, you could probably call an Access Database file from
another Access Database file using a different engine, though I have
not tried it. It's on my to-do list.
Saying that "Access Database" is not a valid way to refer to a file
created in the Access application containing tables that _can_ be
accessed by Jet is in my opinion a bit of a stretch. However, it
does bring up an interesting question, one I don't claim to know the
answer to: if you set up your indexes from within Access, but then
you call the file with another driver, how do the indexes behave?

-Amy

I believe David's point is that one can use other programming environments
like VB to create an MDB containing tables along with an entire
application to interface with that MDB all on a PC that does not even have
Access installed. Would you still call that MDB an "Access Database"?

Absolutely. That's how I use most Access databases I create.

In addition to being able to use a database stored in an MDB file without
using Access one can also build an interface with Access to a non-Jet
database like SQL Server or Oracle. Would you call those "Access
Databases"?

Depending on who I am talking to about it. For most people, probably. Most
people I might need to talk to about it wouldn't understand the distinction,
orcare.


Pedantically, when most people talk about an Access Database, the
*database* is a Jet database and the *application* part is Access. I
usually use the term "Access/Jet" if I mean a database application
consisting completely of MDB files and "Access Application" if I am
talking about the front end to any other database engine.

For me the distinction only matters when the discussion concerns "engine
level" stuff. Discussions about keys, constraints, relationships etc.,
only make sense when you are specific about whether the engine is Jet or
something else.

Again, depends on who you're talking to. Most people understand "Access
database" but couldn't care less what the Jet engine does.

As for your question, you would be using Access to create Jet indexes so
they would still apply when you interface with the database from another
program.

Cool.

"Amy Blankenship" wrote in
:

"David W. Fenton" wrote in message
. 1...
"Amy Blankenship" wrote in
:

Whoah, whoah. Hang on. I was referring to the topic of this
part of the thread, which was the use of primary keys that are
not unique identifiers of the record in order to cluster them on
disk, NOT simply indexing.

Um, how do you set a non-unique index as a PK? The index has to
be unique to qualify as a PK, however artificially you've created
it.

See, that right there argues against his point. You couldn't use
a date, for instance, because that might not be unique but you
might then want to use it as a condition in a BETWEEN clause.

Er, ever heard of compound keys?

--
David W. Fenton http://www.dfenton.com/
usenet at dfenton dot com http://www.dfenton.com/DFA/

"Amy Blankenship" wrote in
:


"David W. Fenton" wrote in message
. 1...
"Amy Blankenship" wrote in
:

"Tim Marshall" wrote in
message ...
Amy Blankenship wrote:

If my Access databases were large enough that indexing were an
issue, they wouldn't be in Access.

OK, I'll leave the church of the not null unique vs. primary
key to you. How many times do you kneel facing Redmond each
day,anyway ;-)?

It is Edgar Codd's legacy to which most of us pay homage, the
platform on which database development takes place is utterly
irrelevant.

I haven't followed this thread, but I have seen this post. No
offence, but you've shown a complete and, if you are anything
close to a "professional" developer, shocking lack of
understanding of relational database design and of "Access" by:

1) Indicating indexing is not an issue; and

2) by referring to "Access databases".

So, you're saying that multiple files created in access are not
Access databases? What do you call them then...?

Just wondering...

We're not talking about Access databases here, but Jet.

Now this is just plain silly. . . .

No, it's not the least bit silly. Discussion in this newsgroup would
go much more smoothly if people maintained the distinction between
Jet and Access in their posts. Often, it's necessary to sort out
what someone is trying to do and whether they are asking about an
Access problem or a Jet problem.

. . . The access file is actually a complete
application that contains, among other things, tables that _can
be_ accessed by the Jet engine, . . .

But indexes RI are *not* an Access feauture, but a Jet features. On
that level we are talking purely about Jet and not about Access at
all.

. . . and are accessed from inside the Access
application (with forms, reports, and module). However, you can
also access the database tables with other engines when calling
the *Access Database* from outside the Access application. In all
probability, you could probably call an Access Database file from
another Access Database file using a different engine, though I
have not tried it. It's on my to-do list.

Who gives a rat's ass?

Saying that "Access Database" is not a valid way to refer to a
file created in the Access application containing tables that
_can_ be accessed by Jet is in my opinion a bit of a stretch. . .
.

Well, the reason you're "upset" is because you have completely
misunderstood the point.

The subject of this thread is *not* an Access issue -- it has
nothing to do with the properties of Jet databases created by Access
that are specific to Access. It is entirely about properties of the
Jet database engine.

. . . However, it does bring up an interesting
question, one I don't claim to know the answer to: if you set up
your indexes from within Access, but then you call the file with
another driver, how do the indexes behave?

Well, d'oh. Through Jet. And only the data is available.

D'oh.

--
David W. Fenton http://www.dfenton.com/
usenet at dfenton dot com http://www.dfenton.com/DFA/