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rockmoose
SQL Natt Alfen

Sweden
3279 Posts

Posted - 08/28/2004 :  13:53:12  Show Profile  Reply with Quote
From time to time we learn and get a deeper understanding of things,
This is when I got involved in relational theory and got a bit confuscated.
Thought I might share this humiliating moment with the nerdiest of Yaks.

rockmoose getting bashed by date

Back to the beer,
/rockmoose

spirit1
Cybernetic Yak Master

Slovenia
11750 Posts

Posted - 08/28/2004 :  14:52:00  Show Profile  Visit spirit1's Homepage  Reply with Quote
learning new stuff every day... :)))



Go with the flow & have fun! Else fight the flow :)
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X002548
Not Just a Number

15586 Posts

Posted - 08/30/2004 :  10:04:24  Show Profile  Reply with Quote
Well, I'm not so sure you got bashed....

But your argument seems more inline with the XML movement...

I guess with Yukon, hierarchies will become all the rage....

Still don't know what that has to do realtionships....




Brett

8-)
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rockmoose
SQL Natt Alfen

Sweden
3279 Posts

Posted - 08/30/2004 :  14:15:47  Show Profile  Reply with Quote
quote:
But your argument seems more inline with the XML movement...
Edit: can't spell qoute today.
My goodness, no. You are just writing that to be mean right

What I was saying was that I thought that the tuples were superfluos when defining the relational model.
A tuple in my eyes were just a relation with cardinality 1.

Anyhow, that is not important now, I was content with the explanation and accept tuples (not as necessary)
but as a convenient type for the definition of the model.

Coming up - my favorite way of parsing XML, just in answer to your comment

/rockmoose

rockmoose
/* Chaos is the nature of things...Order is a lesser state of chaos */

Edited by - rockmoose on 08/30/2004 14:19:30
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rockmoose
SQL Natt Alfen

Sweden
3279 Posts

Posted - 08/30/2004 :  15:26:06  Show Profile  Reply with Quote
quote:
originally posted by rockmoose
Coming up - my favorite way of parsing XML, just in answer to your comment

Ok I was a bit quick here,
basically it's in the lines of search-replace all the bloody tags with '' and ';'
Then BULK INSERT-ing the data.

Just don't have any nifty code to show


rockmoose
/* Chaos is the nature of things...Order is a lesser state of chaos */
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nr
SQLTeam MVY

United Kingdom
12543 Posts

Posted - 09/01/2004 :  10:51:15  Show Profile  Visit nr's Homepage  Reply with Quote
Depends on the format - if it's just a flat representation of records in a table then I do a straight bcp into a single column table using the end tag as ro delimitter then use a function to get the data using the tag as the start delimitter and > as end delimitter for each column.

==========================================
Cursors are useful if you don't know sql.
DTS can be used in a similar way.
Beer is not cold and it isn't fizzy.
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rockmoose
SQL Natt Alfen

Sweden
3279 Posts

Posted - 09/01/2004 :  11:00:34  Show Profile  Reply with Quote
Every time some developer starts rambling abot XML, I just ask Why?
And they have never been able to justify the use, and most of the time
have come to their senses .

So far we have had no business value added whatsoever from using XML.
It has been used in ~2 db applications here, and all it ever did was to
complicate and slow things down.


rockmoose
/* Chaos is the nature of things...Order is a lesser state of chaos */
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byrmol
Shed Building SQL Farmer

Australia
1591 Posts

Posted - 09/02/2004 :  06:35:25  Show Profile  Reply with Quote
There was some nice lines of reasoning in there rockmoose. And I have to back up Brett. A bashing? Date doesn't bash, Pascal on the other hand...but usually the recipient is more than deserving.

I like things simple.. "set of tuples" sounds much more appealing than recursion.

On a slightly different tack...NULL or missing information.

How about we slightly alter the definition from this...
The body is a set of tuples { TV1,TV2,,,TVn } each with the same heading as RV.

To this

The body is a set of tuples { TS1,TS2,,,TSn } each with the same heading as RV, where TS is a Set of type T values.

In practice, the basic data types will be sets of 1 cardinality.. eg. {1}, {2}, {3} etc...
So we could use the empty set to represent our missing info..

Just a thought that's been running around my head......

DavidM

"Always pre-heat the oven"
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rockmoose
SQL Natt Alfen

Sweden
3279 Posts

Posted - 09/03/2004 :  20:27:00  Show Profile  Reply with Quote
quote:
The body is a set of tuples { TS1,TS2,,,TSn } each with the same heading as RV, where TS is a Set of type T values.

In practice, the basic data types will be sets of 1 cardinality.. eg. {1}, {2}, {3} etc...
So we could use the empty set to represent our missing info..


This is somewhat of a marriage between the definition of TUPLE values in TTM(The Third Manifesto) and the concept of DOMAINS.

TTM: A tuple value t is a set of ordered triples in the form <A,T,v>, where:
A is the name of attribute of t.
T is the name of the type of attribute A of t.
v is a value of type T.
.... the marriage ....
Let's define the set of all possible values of a type T value as (S). e.g. [1,2,3,4,5...}
Now the specific value of v is a subset of cardinality 1 from (S) e.g {1}
And the concept of NULL would be the empty subset from (S).
(S) is effectively the DOMAIN of type T.

---------------------------------------------------------------
I think the domain concept is inbedded in your reasoning.

Interesting thought, NULL or missing value is the empty set...
Each non null value is a cardinality 1 subset of the possible values of type T...
Yes, suddenly makes nulls more, shall we say, "pleasing" to look at.

I can go to sleep now
ClaesW

Edited by - rockmoose on 09/03/2004 20:28:54
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Pat Phelan
Posting Yak Master

187 Posts

Posted - 09/09/2004 :  13:28:41  Show Profile  Reply with Quote
Oh heavens yes, I've been debunked many times!

All you need to do is mention my name over there to start rioting. Fabian and I were both featured as "Experts" at another web site, and for reasons that I don't really understand he seems to have taken a great dislike to me.

He's a recognized expert in the field, but his personality consistantly gets in the way of the good that he might be able to do.

After trying multiple times to get him to discuss the points that he was trying to hang me with (mostly by taking quotes out of context so that they appeared very ill-informed), I gave up. Now I just avoid him.

To quote a comment from another expert: "You aren't anybody until he's debunked you at least once!"

-PatP
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