Forum: Ruby Processing postgres table

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Dan W. (Guest)
on 2008-10-22 18:46
I'm using the ruby-postgres gem as ruby-pg isn't installing & as there
no longer seems to be any tutorials or how-tos I thought I'd ask here.

Basically I'm trying to iterate through each row of data and assign the
values to some variables then print them out to XML (XML output's sorted
thanks to builder)
This is one set of that data, one question with 5 answers. How can I go
about finding out the number of rows that contain the same first column?


"A new question by mbr - option 3 is the correct
option";"afsdfsd";"mbr";"";FALSE;"-0.25";"1";"''"

"A new question by mbr - option 3 is the correct
option";"sdfsdf";"mbr";"";FALSE;"-0.25";"2";"''"

"A new question by mbr - option 3 is the correct
option";"sdfsdf";"mbr";"";TRUE;"1.0";"3";"''"

"A new question by mbr - option 3 is the correct
option";"sdfsdf";"mbr";"";FALSE;"-0.25";"4";"''"

"A new question by mbr - option 3 is the correct
option";"sdfsdaf";"mbr";"";FALSE;"-0.25";"5";"''"



This is the current code I'm using for postgres.
db = PGconn.connect(pghost, pgport,'','',pgtbl,dbname,'')
results = db.exec('SELECT question_stem, option_text, author_id,
module_code, correct, weighting, option_id, feedback FROM RESULTS_JOIN')
results.each do |row|
  puts "by position: #{row[0]} #{row[1]} #{row[2]} #{row[3]} #{row[4]}
#{row[5]} #{row[6]} #{row[7]}  "
end

any pointers would be great.
Kind Regards,
Dan
Robert K. (Guest)
on 2008-10-23 16:06
(Received via mailing list)
2008/10/22 Dan W. <removed_email_address@domain.invalid>:
> I'm using the ruby-postgres gem as ruby-pg isn't installing & as there
> no longer seems to be any tutorials or how-tos I thought I'd ask here.
>
> Basically I'm trying to iterate through each row of data and assign the
> values to some variables then print them out to XML (XML output's sorted
> thanks to builder)
> This is one set of that data, one question with 5 answers. How can I go
> about finding out the number of rows that contain the same first column?

SELECT question_stem, count(*)
FROM RESULTS_JOIN
group by question_stem

Cheers

robert
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