HDTenEightyP/NetNews huggingface dataset:
From: mao@triplerock.CS.Berkeley.EDU (Mike Olson)
Newsgroups: comp.databases.theory
Subject: Re: What is the _Halloween Problem_ ?
Date: 29 Aug 1992 17:46:13 GMT
Organization: University of California at Berkeley
NNTP-Posting-Host: triplerock.cs.berkeley.edu

In <BtpLzu.Mzx@world.std.com>, edwards@world.std.com (Jonathan Edwards)
writes:

> In article <17loktINN7mi@agate.berkeley.edu> mao@triplerock.CS.Berkeley.EDU (Mike Olson) writes:
> >transaction semantics force us never to see our own updates, so this is
> >a violation of transaction semantics.
> 
> Why's that? Seem perfectly reasonable to me that I should see my own updates.
> How does this follow from the conventional ACID definition of transactions?

if you want a high level of consistency in transaction processing, you must
supply repeatable reads during a transaction.  this means that inside a
single command in a single transaction, you cannot be allowed to see your
own updates.

lower levels of consistency don't have this requirement, and (as a result)
don't necessarily guarantee serializability of concurrent transactions.
this violates isolatability (the 'i' in acid).

jim gray wrote a paper in the early- or mid-80's defining four consistency
levels, and giving the characteristics of each.  the ref is at work (and
i'm not); email me if you want it, and i'll dig it up.

					mike olson
					project sequoia 2000
					uc berkeley
					mao@cs.berkeley.edu
Newsgroups: comp.databases.theory
From: u9048979@cc.uow.edu.au (glen eastment)
Subject: Re: What constitutes a 4GL?
Organization: University Of Wollongong
Date: Mon, 31 Aug 92 04:51:02 GMT

andrew@airs.com (Andrew Evans) writes:

>At the risk of asking a seemingly trivial question compared to most of
>the other discussion that goes on around here, I'd like an
>authoritative description of what a fourth-generation language really
>is.  In the scope of relational databases, is it simply a programming
>language with a database-oriented syntax?  Or are there more specific
>attributes that a system must have in order to really be a 4GL?
>And who says that this is what a 4GL must be?
>-- 
>Andrew Evans (andrew@airs.com) - Infinity Development Systems - Waltham, MA

I've always believed that a 4GL is where the programmer can specify *WHAT*
he/she wants, without having to specify *HOW* to do it. Sadly, many
4GL still don't come close to this - there is still an amount of *HOW*, and
probably always will be. 4GL's these day are usually bundeled with tools
that take much work out of the *HOW* part - such as screen genrators. As
far as PC's go - I would include applications generating languages such
as DBASE IV as getting pretty close to 4GL's as far as database applications
go (In fact I would include the entire XBase language in this statement).

Anyway, these are my opinions.

Cheers!

<GE> a.k.a. u9048979@wampyr.cc.uow.edu.au
From: cimo@cs.montana.edu (Bob Cimikowski)
Newsgroups: comp.databases.theory
Subject: Database Textbooks
Date: 26 Aug 92 22:11:26 GMT
Article-I.D.: coe.1992Aug26.221126.4975
Organization: CS

Newsgroups: comp.database.theory
Subject: Database texts
Summary: 
Followup-To: 
Distribution: world
Organization: CS
Keywords: 


A few weeks ago I asked for recommendations of good graduate-level database
textbooks.  I have received a number of recommendations so far, which I will
summarize and post shortly.  Mysteriously, none of the replies have mentioned
a text which I seem to like after a preliminary scan --- "Conceptual Database
Design: An Entity-Relationship Approach" (Benjamin-Cummings, 1992) by
Batini, Ceri, and Navathe.  Any comments on this text?  Perhaps it's simply
too new to have been used yet.
Newsgroups: comp.databases.theory
From: olea@hal.nta.no (Ole J. Anfindsen FDA)
Subject: The problem of missing information
Keywords: nil null
Organization: Norwegian Telecom Research
Date: Fri, 28 Aug 92 11:57:38 GMT


I am currently doing some work related to the Problem of Missing Information.
Below are the references I have gathered so far.  If anyone is able to 
supply further references, it will be highly appreciated.  Thanks in advance!

My references:

E F Codd, Missing Information (appl and inappl) in Relational Databases,
SIGMOD RECORD, Vol 15, No 4, December 1986.

E F Codd, More commentary on missing information in relational databases
(appl and inappl information), SIGMOD RECORD Vol 16, No 1, March 1987.

E F Codd, The relational model for database management: version 2,
Addison-Wesley, 1990.

C J Date, "NOT is Not 'Not'", from Relational Database Writings 1985-1989,
Addison-Wesley, 1989.

Andrew Warden, Into the Unknown, special contribution in the above mentioned
book by C J Date.

S Danforth and P Valduriez, The Data Model of FAD, a Database Programming
Language, Information Sciences, Vol 60, No 1-2, 1992.

C Zaniolo, Database relations with null values, J. Comput. Syst. Sci.,
28(1), 1984.

-- 
Ole J. Anfindsen 
Norwegian Telecom Research
E-mail:  ole.anfindsen@nta.no

Newsgroups: comp.databases.theory
From: kean@cs.ubc.ca (Alex Kean)
Subject: Re: What is the _Halloween Problem_ ?
Organization: Computer Science, University of B.C., Vancouver, B.C., Canada
Date: Fri, 28 Aug 92 18:28:42 GMT


What is a good reference for this problem? 

Best Regards,

Alex Kean <kean@cs.ubc.ca>

Department of Computer Science           
University of British Columbia
6356 Agricultural Road,
Vancouver, British Columbia
Canada V6T 1Z2

Tel: +1 (604)-822-4912
Fax: +1 (604)-822-5485

Newsgroups: comp.databases.theory,comp.databases
From: rys@apelc8.inf.ethz.ch (Michael Rys)
Subject: Re: Different representation of entity-relation diagrams
Organization: Dept. Informatik, Swiss Federal Institute of Technology (ETH), Zurich, CH
Distribution: usa
Date: Fri, 28 Aug 1992 09:05:36 GMT

There is also this notation:

|> One-to-One:
|> 	+----------+          /----------\          +----------+
|> 	| Entity_1 | <------- | Relation | -------> | Entity_2 |
|> 	+----------+          \----------/          +----------+

 	+----------+   (a,1)   /----------\   (a,1)   +----------+
 	| Entity_1 | --------- | Relation | --------- | Entity_2 |
 	+----------+           \----------/           +----------+

|> One-to-Many:
|> 	+----------+          /----------\          +----------+
|> 	| Entity_1 | <------- | Relation | ------>> | Entity_2 |
|> 	+----------+          \----------/          +----------+

 	+----------+   (a,1)   /----------\   (b,n)   +----------+
 	| Entity_1 | --------- | Relation | --------- | Entity_2 |
 	+----------+           \----------/           +----------+

|> Many-to-One:

viceversa.

where:

a = 0 or 1.
b = 0, 1 or n.
n > 1 or *.

The type of the above relation can be represented as:

RelT = <Ent1T, Ent2T>

To express the cardinality, we use:

card(RelT) = < (x1,y1), (x2,y2) >       where xi, yi = b.

The first number xi of the tuple gives the required minimal number of the
Entity_i in that relation, yi the required maximal number. 

This information belongs to the integrity constraints of the data model.

For example:

Works_ForT = <EmpT, ChefT>
card(Work_ForT) = < (1,1), (1,*) >

means

Every employee has exactly one chef, each chef has at least one employee.
Thus, this is a strict hierarchical relation.

Hope this helps
Michael
--
Michael Rys     Institute for Informationsystems/Databases     ETH Zuerich
Voice: priv. +41 1 242 35 87   bus. +41 1 254 72 57   Fax: +41 1 262 39 73
    -- Wovon man nicht sprechen kann, darueber muss man schweigen. --
          Ludwig Wittgenstein, Tractatus logico-philosophicus
From: davidm@consilium.com (David S. Masterson)
Newsgroups: comp.databases.theory
Subject: Re: ordered collections
Date: 2 Sep 92 18:28:13 GMT
Organization: Consilium Inc., Mountain View, California
In-reply-to: cdk@neptune.dsc.com's message of 1 Sep 92 15:49:12 GMT
X-Posting-Software: GNUS 3.13  [ NNTP-based News Reader for GNU Emacs ]

>>>>> On 1 Sep 92 15:49:12 GMT, cdk@neptune.dsc.com (Colin Kelley) said:

> Is there a standard way to implement ordered collections in a relational
> database that would allow for random insertion?  You could always have a
> sequence number field to remember the ordering, but if you want random
> insertion, you may run out of bits in this sequence number and not be able
> to insert a new entry between two others.

Well, I don't think there is a standard, but here's one way.

1. Make the primary key be (sequence_number, current_date).
2. Generate a new sequence_number for additions to the end of the collection.
3. Insertion anywhere else uses the sequence_number of preceding item.

--
====================================================================
David Masterson					Consilium, Inc.
(415) 691-6311					640 Clyde Ct.
davidm@consilium.com				Mtn. View, CA  94043
====================================================================
Trying to shoot yourself in the foot in:
CLIPPER:  You grab a bullet, get ready to insert it in the gun so that you 
        can shoot yourself in the foot, and discover that the gun that the 
        bullet fits has not yet been built, but should be arriving in the mail
        _REAL_SOON_NOW_.  <rboatright>
From: dtb@otto.bf.rmit.oz.au (David Bath)
Newsgroups: comp.databases.theory
Subject: Re: What constitutes a 4GL?
Date: 27 Aug 92 01:21:19 GMT
Organization: RMIT Computer Centre, Melbourne Australia.

andrew@airs.com (Andrew Evans) writes:

>At the risk of asking a seemingly trivial question compared to most of
>the other discussion that goes on around here, I'd like an
>authoritative description of what a fourth-generation language really
>is.  In the scope of relational databases, is it simply a programming
>language with a database-oriented syntax?  Or are there more specific
>attributes that a system must have in order to really be a 4GL?
>And who says that this is what a 4GL must be?
>-- 

4GL is usually marketroid hype for a language without the power and
flexibility of C, i.e. one users can generate unspecified untested and
undesigned programs in quickly.

Seriously productive languages rely on
(1) decent syntax (e.g. C, C++, perl) flexibility
(2) decent variable addressing
(3) decent function libraries

Note
(1) Pointers are the hottest thing since bits were invented
(2) I have not seen a 4GL that lets you use pointers (or esp
invoke a function indicated by a pointer)

Ergo
	Give me beaten up K&R C (the old testament) over any 4GL
	I have seen ANY DAY OF THE MILLENIUM.

If you want to get productive with a database, use embedded C to
create TINY ONE FUNCTION C interfaces to the database and put these
in a library.  Use these functions and forget about your precompiler.
(OK - so this requires an investment - but you do not have to deal
with grotty precompiler limitations any more and can use cb, ctrace,
ctags etc etc etc on most of your code rather than .000001% of it)

========================================================================
David T. Bath
email: 	dtb@otto.bf.rmit.oz.au
Work: 	Global Technology Corporation, Carlton, Vic, OZ  (03) 3477511
=======================================================================
From: shu@cs.purdue.EDU (Lih-Chyun Shu)
Newsgroups: comp.databases.theory
Subject: Comments on J. Gray's new book?
Date: 27 Aug 92 01:31:23 GMT
Organization: Department of Computer Science, Purdue University

Could someone comment on the new book "Transaction Processing:
Concepts and Techniques" by Jim Gray and Andreas Reuter? Thanks.
-- 
Lihchyun Shu                  e-mail : shu@cs.purdue.edu
Dept. of Computer Sciences
Purdue University
West Lafayette, IN 47907
Newsgroups: comp.databases.theory
From: u9048979@cc.uow.edu.au (glen eastment)
Subject: Re: What constitutes a 4GL?
Organization: University Of Wollongong
Date: Wed, 2 Sep 92 02:50:45 GMT

>I think Douglas was close in his comments about 4GLs.  And the slams were deserved.

>You might consider the name "4th Generation language" - it comes from a series of
>language classifications with 1st being machine language, 2nd being assembly and 3rd
>being C and other "more human-oriented" languages.  I was taught that these levels
>of languages represent productivity for programmers.  It was calculated at some
>point that an assembly language programmer could work more than 10 times faster than
>a machine language programmer (a magnitude or generation) and Cobol/Fortran/C/Pascal/etc.
>programmers could work more than 10 times faster than assembly programemrs, etc.....

>4GLs therefore should be at least 10 time more productive than 3GLs.

I read somewhere, that the productivity of programmers has only increased by
a few per cent since the beginning of computing - if this is true (and I am
*not* necessarily saying that it is), then it just about throws out the above
theory.

>I have heard a lot of other defenitions about 4GLs, but most were Marketing Hype that
>companies use to disqualify competiters.

>Sean
> 

Cheers!

<GE> a.k.a. u9048979@wampyr.cc.uow.edu.au


Newsgroups: comp.databases.theory
From: jah@cs.mu.OZ.AU (James Harland)
Subject: Deadline Extension for Workshop on Deductive Databases at JICSLP'92
Originator: jah@munta.cs.mu.OZ.AU
Reply-To: jah@cs.mu.OZ.AU (James Harland)
Organization: Department of Computer Science, University of Melbourne
Date: Fri, 4 Sep 1992 07:13:26 GMT



	Due to several requests for an extension to the deadline of
September 7, the new deadline for submissions for the Workshop on Deductive
Databases at JICSLP'92 is SEPTEMBER 11. A revised CFP is given below. 


		 Final Call for Participation

		Workshop on Deductive Databases
	         Saturday, 14 November, 1992
		    in conjunction with the
       Joint International Conference and Symposium on Logic Programming
		November 9-13, 1992, Washington D.C., USA

The development of deductive database systems, which apply logic
programming techniques to databases, has been of growing interest in recent
years, and has resulted in a significant amount of interaction between
researchers of varying backgrounds. This workshop is intended to provide a
forum for theoreticians, implementors and those involved in applications to
exchange ideas on the development of deductive databases systems. Topics
may include (but need not be limited to) program transformations, parallel
and distributed execution, optimization and implementation techniques, and
applications.

Abstracts and/or proposals for system demonstrations should be send to the
address below:

	 Prof. Kotagiri Ramamohanarao
	 Department of Computer Science
	 University of Melbourne
	 Parkville, 3052
	 Australia

	 email: rao@cs.mu.oz.au
	 Phone: +61 3 282 2400
	 Fax:   +61 3 282 2444

Abstracts should be no more than 8-10 pages in length, and there is no
restriction on the format to be used. However, Latex/Tex format is
preferred, particularly styles similar to those used for submissions and/or
camera-ready copy for the main conference. Submission by email rather than
printed copies is strongly encouraged. 

Copies of all accepted abstracts will be distributed to participants at the
workshop. In order to provide continued access to the abstracts presented
at the workshop, the proceedings will be available as a University of
Melbourne technical report.

Submission Dead-line: September 11, 1992 (extended from September 7)
Notification Sent: October 1, 1992
Final Manuscript Due: October 15, 1992

Organizing Committee: Kotagiri Ramamohanarao, Guozhu Dong, James Harland
 

Newsgroups: comp.databases.theory
From: engp2190@nusunix3.nus.sg (ZENG YONGNING)
Subject: Temporal Database
Organization: National University of Singapore
Date: Sat, 29 Aug 1992 08:02:57 GMT
From: kencham@ulysses.cs.umn.edu (Deepak)
Newsgroups: comp.databases.theory
Subject: Re: What is the _Halloween Problem_ ?
Date: 28 Aug 92 16:10:50 GMT
Organization: University of Minnesota

Ho gurus,

Thanks for the clarification. But one doubt still persists .....

Consider the following table :

	table OneK {

	TYPE unique2 ; /* This is a primary key for the table */
	..........
		};

Consider the query,

	Update OneK
	Set unique2 = 10002
	where unique2 == 10001;

According to some systems, this is an instance of the 
_Halloween Problem_. How ? Besides violation of entity constraint 
what is the other problem that makes it _HP_ for some systems.

Thanks, in advance
PS: Exact syntax etc.. may be overlooked.
-- 
* Deepak R. K..........-H.......  * 	    	    	        *
* D........ of C...... S......    * Underneath the surface of,  *
* U......... of M........         * Sai Baba,	    	    	*
* 1:(  (612) 626-8396(o),         * Life is a Cobra.	    	*   
*      (612) 339-8997(r) )        * - Seljut Veljet (Softwood) 	*
* kencham@ulysses.cs.umn.edu      * 	    	    	    	*
From: adf@cs.utexas.edu (Angela Dappert-Farquhar)
Newsgroups: comp.databases.theory
Subject: Order-preserving hashing
Date: 26 Aug 1992 10:19:56 -0500
Organization: CS Dept, University of Texas at Austin
NNTP-Posting-Host: earth.cs.utexas.edu

Could anyone please point me to the most relevant papers on
order-preserving hashing algorithms!

  Thanks a lot,

    Angela

------------------------------------------------------------------
Angela Dappert-Farquhar                          adf@cs.utexas.edu
Department of Computer Sciences                     (512) 471-9576
Taylor Hall 2.124
The University of Texas at Austin
Austin, TX 78712
From: jeffl@houdini.sybase.com (Jeff Lichtman)
Newsgroups: comp.databases.theory
Subject: Re: What is the _Halloween Problem_ ?
Date: 2 Sep 92 20:13:06 GMT
Organization: Committee to Increase The Entropy

In article <BtpLzu.Mzx@world.std.com>, edwards@world.std.com (Jonathan Edwards) writes:
> In article <17loktINN7mi@agate.berkeley.edu> mao@triplerock.CS.Berkeley.EDU (Mike Olson) writes:
> >transaction semantics force us never to see our own updates, so this is
> >a violation of transaction semantics.
> 
> Why's that? Seem perfectly reasonable to me that I should see my own updates.

A single statement should not see the results of its own updates.  In other
words, a statement should base its updates on the state of the data at the time
the statement begins.  To do otherwise would allow for unpredictable and
inconsistent results.  I have already posted an example of this.

This is different from saying that one statement in a transaction should be
able to see the results of an earlier update in the same transaction.  I think
everyone agrees that this should happen.
---
Jeff Lichtman at Sybase
{mtxinu,pacbell}!sybase!jeffl  -or- jeffl@sybase.com
"Saints should always be judged guilty until they are proved innocent..."
Newsgroups: comp.databases.theory
From: kencham@ulysses.cs.umn.edu (Deepak)
Subject: What is the _Halloween Problem_ ?
Organization: University of Minnesota
Date: Mon, 24 Aug 1992 00:07:20 GMT

DB gurus,

What is the _Halloween Problem_ ? Could someone give me some insight 
reference as to what this problem is ?

Thanks, in advance.
-- 
* Deepak R. K..........-H.......  * So long as one knows.    	     *
* D........ of C...... S......    * One can bide one's time. 	     *
* U......... of M........         * One knows what to expect.	     *
* 1:(  (612) 626-8396(o),         * No further need to worry.	     *
*      (612) 339-8997(r) )        * Simply wait,    	    	     *
* kencham@ulysses.cs.umn.edu      * We're used to it. (SB in _WforG_)*
Newsgroups: comp.databases.theory
From: sean@Unify.com (Sean P. Curley)
Subject: Re: What constitutes a 4GL?
Organization: Unify Corporation (Sacramento)
Date: Mon, 31 Aug 92 18:07:42 GMT

In article <1992Aug31.045102.25682@cc.uow.edu.au>, u9048979@cc.uow.edu.au (glen eastment) writes:
> andrew@airs.com (Andrew Evans) writes:
> 
> >At the risk of asking a seemingly trivial question compared to most of
> >the other discussion that goes on around here, I'd like an
> >authoritative description of what a fourth-generation language really
> >is.  In the scope of relational databases, is it simply a programming
> >language with a database-oriented syntax?  Or are there more specific
> >attributes that a system must have in order to really be a 4GL?
> >And who says that this is what a 4GL must be?
> >-- 
> >Andrew Evans (andrew@airs.com) - Infinity Development Systems - Waltham, MA
> 
> I've always believed that a 4GL is where the programmer can specify *WHAT*
> he/she wants, without having to specify *HOW* to do it. Sadly, many
> 4GL still don't come close to this - there is still an amount of *HOW*, and
> probably always will be. 4GL's these day are usually bundeled with tools
> that take much work out of the *HOW* part - such as screen genrators. As
> far as PC's go - I would include applications generating languages such
> as DBASE IV as getting pretty close to 4GL's as far as database applications
> go (In fact I would include the entire XBase language in this statement).
> 
> Anyway, these are my opinions.
> 
> Cheers!
> 
> <GE> a.k.a. u9048979@wampyr.cc.uow.edu.au

I think Douglas was close in his comments about 4GLs.  And the slams were deserved.

You might consider the name "4th Generation language" - it comes from a series of
language classifications with 1st being machine language, 2nd being assembly and 3rd
being C and other "more human-oriented" languages.  I was taught that these levels
of languages represent productivity for programmers.  It was calculated at some
point that an assembly language programmer could work more than 10 times faster than
a machine language programmer (a magnitude or generation) and Cobol/Fortran/C/Pascal/etc.
programmers could work more than 10 times faster than assembly programemrs, etc.....

4GLs therefore should be at least 10 time more productive than 3GLs.

I have heard a lot of other defenitions about 4GLs, but most were Marketing Hype that
companies use to disqualify competiters.

Sean
 
Newsgroups: comp.databases.theory
From: srb@barakam.b17d.ingr.com (Sreedhar Barakam)
Subject: Request for literature from MIT.
Organization: Intergraph Corp.,
Distribution: usa
Date: Wed, 26 Aug 1992 18:41:17 GMT

I am looking for two technical reports from Computer Science dept. of MIT.

They are:

1. WK. Serv. Kerberos authentication at Project Athena
   by Don Davis 1990(8pages)

2. Adding Kerberos authentication QUIPU Implementation (24 pages) 1991.

.. and any followups to this work.

I tried to reach a e-mail distribution list to kerberos-request@mit.edu
as well as a contact tytso@mit.edu but to no avail.  If anybody has these
reports or any information, it will be greatly appreciated.


Thanks in advance.

Sreedhar Barakam.
srb@barakam.b30.ingr.com
Newsgroups: comp.databases.theory
From: hyu@eng.umd.edu (Henry K. Yu)
Subject: Different representation of entity-relation diagrams
Date: Thu, 27 Aug 92 15:41:14 GMT
Organization: University of Maryland, College Park, College of Engineering
Distribution: usa

The entity-relation diagrams that I hav been taught specify relation
between entities:
One-to-One:
	+----------+          /----------\          +----------+
	| Entity_1 | <------- | Relation | -------> | Entity_2 |
	+----------+          \----------/          +----------+
One-to-Many:
	+----------+          /----------\          +----------+
	| Entity_1 | <------- | Relation | ------>> | Entity_2 |
	+----------+          \----------/          +----------+
Many-to-One:
	+----------+          /----------\          +----------+
	| Entity_1 | <<------ | Relation | -------> | Entity_2 |
	+----------+          \----------/          +----------+

Recently, another method was presented to me.  And, I don't understand how it
works.  It specifies the type of relations between each entity and relation,
not between entity and entity.

	+----------+   XXXX   /----------\   XXXX   +----------+
	| Entity_1 | -------- | Relation | -------- | Entity_2 |
	+----------+          \----------/          +----------+

Where 'XXXX' can be one of 0:0, 0:1, 1:0, 0:N, N:0, 1:1, 1:N, N:1, N:N.

Supposely, someone from MIT came up with this method.  Can someone explain
the advantage of this method?  How about ways to map from the former to the
latter method and vice versa?

Thanks,
hyu