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  • 0 posts edited
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  • 15 votes cast
Apr
20
awarded  Yearling
Apr
10
answered Column partially determining accepted values of another column, should be somehow normalized?
Apr
3
comment Handling expiration in a course registration or ticketing system
And in addition, create views such as REGISTRATION_EXPIRED_WITHOUT_PAYMENT and REGISTRATION_UNPAID_UNEXPIRED.
Apr
3
answered What happens to a Trigger if a table is dropped and rename and recreated with same name
Mar
28
awarded  Quorum
Mar
13
comment Representing SQL constraints on a table
Chris, The accepted answer in that post does not give a declarative solution, and the answer by AKuznetzov forces three extra columns upon the user, and I'm not sure it is entirely impossible for the user to have the integrity test fail because of mistakes in those extra three columns.
Mar
12
comment Representing SQL constraints on a table
Even if he dropped the floor condition, can he have his constraint enforced declaratively with those engines that you mention ?
Mar
12
answered Performing SELECT on EACH ROW in CTE or Nested QUERY?
Mar
2
answered Why is optimistic locking faster than pessimistic locking?
Mar
2
comment Why is optimistic locking faster than pessimistic locking?
No it doesn't. That's why it's "faster".
Feb
20
comment Database functional dependency BCNF help
As far as normal forms theory is concerned, yes. As far as logical database design is concerned, remember that xNF is not where the story ends.
Feb
19
answered Database functional dependency BCNF help
Feb
19
answered Multiple primary keys
Feb
18
comment ORDER BY clause is allowed over column that is not in SELECT list?
Or it wouldn't. A table is explicitly defined by the standard to be an "unordered collection of rows". Make that fit with ORDER BY clauses ...
Feb
18
comment ORDER BY clause is allowed over column that is not in SELECT list?
For the problem the OP describes, just putting the ORDER BY before the SELECT will do the job. Don't read too much into these kinds of "flowcharts of query processing". They are rarely intended for being 100% accurate and complete. Rather, they are intended for illustrating somewhat globally what goes on as a consequence of an SQL statement being issued.
Feb
14
answered Where can I find the SQL standard document?
Feb
1
comment What is the correct result for this query?
@Kevin did you ask ISO for permission to copy ? :-)
Jan
29
comment What is the correct result for this query?
Well the key issue is whether it's indeed true that "even if the table has no rows at all, it's still one group of 0 rows". And the standard turns out to be explicit about this : "If there are no grouping columns, then ... is the grouped table consisting of T as its only group". (and that holds even if T is empty - so there is indeed a group.) Further on, the having clause specifies that the condition is applied to each group (in the example thus once). They probably defined it this way to make SUM and COUNT return one row even for empty T's.
Jan
29
answered Looking for a scalable relational database
Jan
24
comment How to tackle a large undocumented database
Think before you comment. The OP explicitly stated that he was the ONLY It guy. So who are those developers ? External contractors perhaps, who were paid for nothing more than just the time it took to build the thing ? Why would those be willing to put in their time for additional support, which company X probably has been unwilling to pay for to begin with ? Or were they perhaps former employees who got laid off because they were too expensive ? Why would they put in their time to help out company X with its problems ? And who is going to get hurt by dropping tables ?