Re: DBA quiz

In article <3aa2f53b.17404726_at_news.gte.net>, JRStern says...
>
>Right, so what is the point of presenting it in an interview?

No, no, that's not my point. It's about constraint programming, isn't it? Here is what can be done with the above SQL:

1. What is the easiest question -- the one that could be deduced first. I would probably try something like

select distinct ai from ...
where question #j

to check if the answer ai could be deduced solely from question #j.

If there no such question/answer pairs exists, the problem is for the machine and not for human being. (Hmm, when did I multiply huge numbers by hand last time?)

2. How does one build such a puzzle? Would I simply throw in new constraints until the only solution is possible?

3. How about search tree approach? Could the constraints defy any split-and-concure strategy?

In article <FFxo6.1570$45.1949_at_www.newsranger.com>, Vadim Tropashko says...
>
>That's SRAT from
>
>Martin Henz. Don't be puzzled! In Proceedings of the Workshop on Constraint
>Programming Applications, in conjunction with the Second International
>Conference on Principles and Practice of Constraint Programming (CP96),
>Cambridge, Massachusetts, USA, August 1996.
>
>There is a lot of web references as well.
>
>If you don't like going procedural, here is SQL solution:
>
>create table ANSWERS (
>answer CHAR(1);
>)
>
>insert into ANSWERS values ('A');
>insert into ANSWERS values ('B');
>insert into ANSWERS values ('C');
>insert into ANSWERS values ('D');
>insert into ANSWERS values ('E');
>
>Since SQL doesn't support implication "A->B" directly, it is represented as "not
>A or B", which makes the query somewhat less readable.
>
>The query:
>^^^^^^^^^^
>
>select * from (select t1.answer a1, t2.answer a2, t3.answer a3, t4.answer a4,
>t5.answer a5, t6.answer a6, t7.answer a7, t8.answer a8, t9.answer a9, t10.answer
>a10
>from answers t1, answers t2, answers t3, answers t4, answers t5
>,answers t6, answers t7, answers t8, answers t9, answers t10)
>where (
>-- #1
>(a1<>'A' or (a2='B' and a1<>'B') ) -- (A)
>and (a1<>'B' or (a3='B' and a1<>'B' and a2<>'B') ) -- (B)
>and (a1<>'C' or (a4='B' and a1<>'B' and a2<>'B' and a3<>'B') ) -- (C)
>and (a1<>'D' or (a5='B' and a1<>'B' and a2<>'B' and a3<>'B' and a4<>'B') ) --
>(D)
>and (a1<>'E' or (a6='B' and a1<>'B' and a2<>'B' and a3<>'B' and a4<>'B' and
>a5<>'B') ) -- (E)
>) and ( -- #2
>(a2<>'A' or (a2=a3 and a1<>a2 and a3<>a4 and a4<>a5 and a5<>a6 and
>a6<>a7 and a7<>a8 and a8<>a9 and a9<>a10) ) -- (A)
>and (a2<>'B' or (a3=a4 and a1<>a2 and a2<>a3 and a4<>a5 and a5<>a6 and
>a6<>a7 and a7<>a8 and a8<>a9 and a9<>a10) ) -- (B)
>and (a2<>'C' or (a4=a5 and a1<>a2 and a2<>a3 and a3<>a4 and a5<>a6 and
>a6<>a7 and a7<>a8 and a8<>a9 and a9<>a10) ) -- (C)
>and (a2<>'D' or (a5=a6 and a1<>a2 and a2<>a3 and a3<>a4 and a4<>a5 and
>a6<>a7 and a7<>a8 and a8<>a9 and a9<>a10) ) -- (D)
>and (a2<>'E' or (a6=a7 and a1<>a2 and a2<>a3 and a3<>a4 and a4<>a5 and
>a5<>a6 and a7<>a8 and a8<>a9 and a9<>a10) ) -- (E)
>) and ( #3
>(a3<>'A' or (a10=a3) ) -- (A)
>and (a3<>'B' or (a9=a3 and a10!=a3) ) -- (B)
>and (a3<>'C' or (a8=a3 and a10!=a3 and a9!=a3) ) -- (C)
>and (a3<>'D' or (a7=a3 and a10!=a3 and a9!=a3 and a8!=a3) ) -- (D)
>and (a3<>'E' or (a6=a3 and a10!=a3 and a9!=a3 and a8!=a3 and a7!=a3) )
>-- (E)
>) and (
>(a4<>'A' or CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')=0 ) --
>(A)
>and (a4<>'B' or CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')=1 ) --
>(B)
>and (a4<>'C' or CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')=2 ) --
>(C)
>and (a4<>'D' or CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')=3 ) --
>(D)
>and (a4<>'E' or CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')=4 ) --
>(E)
>) and (
>(a5<>'A' or a10=a5 ) -- (A)
>and (a5<>'B' or a9=a5 ) -- (B)
>and (a5<>'C' or a8=a5 ) -- (C)
>and (a5<>'D' or a7=a5 ) -- (D)
>and (a5<>'E' or a6=a5 ) -- (E)
>) and (
>(a6<>'A' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')=CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'B')
>) -- (A)
>and (a6<>'B' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')=CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'C')
>) -- (B)
>and (a6<>'C' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')=CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'D')
>) -- (C)
>and (a6<>'D' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')=CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'E')
>) -- (D)
>--and (a6<>'E' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')=CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')
>) -- (E)
>) and (
>(a8<>'A' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'E')=2
>) -- (A)
>and (a8<>'B' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'E')=3
>) -- (B)
>and (a8<>'C' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'E')=4
>) -- (C)
>and (a8<>'D' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'E')=5
>) -- (D)
>and (a8<>'E' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'A')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'E')=6
>) -- (E)
>) and (
>(a9<>'A' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'B')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'C')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'D')
>in (2,3,5,7) ) -- (A)
>and (a9<>'B' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'B')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'C')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'D')
>in (1,6) ) -- (B)
>and (a9<>'C' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'B')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'C')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'D')
>in (0,1,4,9) ) -- (C)
>and (a9<>'D' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'B')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'C')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'D')
>in (0,1,8) ) -- (D)
>and (a9<>'E' or
>CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'B')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'C')+CHARCOUNT(a1||a2||a3||a4||a5||a6||a7||a8||a9||a10,'D')
>in (0,5,10) ) -- (E)
>)
>
>It returns ten rows, but I skipped one question
Received on Mon Mar 05 2001 - 20:42:00 CET