Re: cdt glossary - TABLE
Date: Thu, 14 Jul 2005 02:15:27 +0200
Message-ID: <42d5ae9e$0$32141$e4fe514c_at_news.xs4all.nl>
Paul wrote:
> dawn wrote:
>
>>Do you call the result of a SQL/relational query a "table" or just >>stick with "set"? I would guess that people would intuitively consider >>a result set to be a table. We can define it either way and usually >>whether it is ordered or not is not relevant, but when we have a need >>for precision, it would be good to know which is most commonly >>accepted.
>
> I tend to use the words "table" and "relation" as synonyms when talking
> about databases, mainly for pedagogical reasons; maybe I shouldn't
> though. I just think people new to databases get confused by the term
> "relation" and think it's something to do with the relationships between
> tables - I think I certainly did. If I want to talk about SQL tables
> which may have duplicate rows I'd use the term "SQL tables".
Basically I agree. On a similar note: When discussing ER I tend to avoid 'relationship' and use 'association' (to avoid confusion with 'relation') - at the end I rectify.
However, it's been a while since I adressed a naive audience (i.e. not having ideas, skewed by either Oracle, DB2 or OO - e.g. Hibernate, google for it) - so maybe I should say I used to agree - and would agree if I'ld get the chance again.
>>Do models other than the relational model use the term "table" and, if >>so, do these models define "table" to be the same as relational >>theorists define it? I think of a table as being able to be modeled >>with a mathematical matrix, but I might not be considered a good >>relational disciple ;-)
>
> Loads of words are overloaded with meaning so I think we're onto a
> losing battle trying to have definitions that are consistent across
> disciplines!
A valuable database manifests a language or at least a dialect in an organisation. You simply cannot afford to avoid multidisciplinarity. Consistency across may be out of reach, but mutual respect is not.
> A table in relational database-speak could be totally different to a
> table in math-speak or HTML-speak or even SQL-speak.
>
> In most non-RDBMS contexts a table would be considered to have order of
> both columns and rows, I'd say, just like a mathematical matrix. But all
> this is just convention really.
Don't underestimate convention. Received on Thu Jul 14 2005 - 02:15:27 CEST