Re: Proposal: 6NF

Cimode wrote:
[..]
> My advice is to dump *politically correct* approaches. SQL NULL is not
> a better treatment of missing data. It is poor (in a word you don't
> have to choose between pest and cholera).

This phrasing is so unbecoming...the sky is definitely not falling!

> Not convinced? Tons of arguments and proofs were presented to make a
> case against them..Another proof, run this in SQL ORACLE, SQL Server or
> DB2

Should I try it on Sybase ASE 12.5?

> create table table1(field1 int, field2 varchar(1))
> go
> insert table1
> select 1, 'A'
> insert table1
> select 2, 'B'
> insert table1
> select 3, 'C'
> insert table1
> select NULL, 'B'

Hmmm - the last statement fails...as it should! Maybe that is why you only got 3 rows back :-).

> --Query1/ The following should return ALL records whether NULL or not
> select * from table1 where field2 = field2

Hmmm - ASE returns all rows.

> --it turns out it return 3 out of 4 records --therefore we could
> conclude that the system considers that NULL <> NULL Right? (opposite
> of = should be <> right?)

This is wacky - trying to rationalise 3VL by clutching at 2VL thinking is very trippy.

> Next run...
> select * from table1 where field2 <> field2 to get the NULL value and

Hmmm - ASE returns no rows as I expect.

> the system returns no records which is madness because the system
> NEITHER considers NULLS as being = NOR <> from one another...As a
> result, all counts on tables including NULLS can only be WRONG...I do
> not care whether other technologies do worse....This is bad enough...

Even allowing for your likely intent to store the NULL in field2 as ...

    create table table1(field1 int, field2 varchar(1) null) and

    insert table1 select 4,NULL
the first query returns 3 rows as expected and the second returns no rows...as expected!

QED the "Proof" crashes and burns!

[..]

Seems all very deterministic to my untrained eye - whachoubinsmokinboy!!

Cheers, Frank. Received on Sun Oct 08 2006 - 03:59:36 CEST