Is SQL a good language for this problem ?

#31

Ed Prochak said:

Quote:

On Jul 11, 2:56 pm, Richard Robinson <richa... (AT) privacy (DOT) net> wrote:
Gene Wirchenko said:
Ed Prochak <edproc... (AT) gmail (DOT) com> wrote:

The point is, in a RELATIONAL database you have a relation between the
primary key and the dependent attributes. IOW, you only need one table
with at least two columns to have a relation.

Nope. You can have a relation with only one column. It would be
purely a lookup, but you could.

Ok. So, a single table having only one column and only one row ... ?

Gene is more of a purist than I am, and Yes, a single column table is
technically a relation. (the number of rows does not matter).

Ok. It'll be a while before I stop finding it unexpected, but I'll get used
to it.

Quote:

makes a good point that I overlooked. If you need a list of something,
say colors, then you can have a COLORS table with one column COLOR,
the PK is that one column. There is no use in creating a ID column to
be the PK. Then you can have a CARS table with a COLOR column that is
a Foreign Key referencing the COLOR column of the COLORS table. That
way you cannot put a COLOR value in the CARS table that is not in the
COLORS table.

Ah. Yes, I can see the point of that; thanks for explaining it.

--
Richard Robinson
"The whole plan hinged upon the natural curiosity of potatoes" - S. Lem

My email address is at http://www.qualmograph.org.uk/contact.html

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Is SQL a good language for this problem ?

comp.databases comp.databases

Re: Is SQL a good language for this problem ? - 07-12-2007 , 09:18 AM