sql tables
Date: Thu, 11 Oct 2007 15:21:08 GMT
Message-ID: <EbrPi.13483$Da.2157_at_pd7urf1no>
(note, I changed the thread subject)
Bob Badour wrote:
I presume David could just as well have said "an SQL DBMS manipulates
SQL tables". Found (finally) a copy of some draft or other of the SQL
standard at http://www.contrib.andrew.cmu.edu/~shadow/sql/sql1992.txt .
Not sure how this copy might differ from the official ones, but anyway,
here's some of what it says in section 4.9 which seems to be about
"Concepts":
> David Cressey wrote:
> ...
>> An SQL DBMS manipulates tables, not relations or relational variables.
>
> Exactly.
> 4.9 Tables
I'm wondering if there are popular SQL dbms's that follow this. For
example, do any of them let me "insert", say, two "rows" that would be
considered the same row if a table were a set of rows rather than a
multiset of rows, giving, eg.:
TableA:
>
> A table is a multiset of rows. A row is a nonempty sequence of
> values. Every row of the same table has the same cardinality and
> contains a value of every column of that table. The i-th value in
> every row of a table is a value of the i-th column of that table.
> The row is the smallest unit of data that can be inserted into a
> table and deleted from a table.
ColumnA
1
(all other things being equal)? Received on Thu Oct 11 2007 - 17:21:08 CEST