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From: Mitja Čebokli on 16 Apr 2010 06:56
Hello,

i am very new to ruby and i have a major problem i would like to have
some help on...

I would like to execute a query on a database and export the values to
the CSV file. I have tried many different ways and i can't get it to
work.

This is what i have so far:

require 'oci8'
require 'csv'

time = Time.now
rows =[]

connection = OCI8.new("user", "pass", "srv")
dataset = connection.exec("select column from table")
while r = dataset.fetch()
rows << r.join("\n")
end
dataset.close
connection.logoff

CSV.open("c:\\Temp\\test_"+time.strftime("%d-%m-%Y_%H-%M")+".csv","w",:col_sep
=> ";") do |csv|

rows.each do |row|
csv << row
end
end

I am getting this error:
csv.rb:1700 undefined method 'map'

What i want to achieve is pretty simple:
- have a header with names of columns from the database (automatic)
- write a CSV file with each record as a new line
- have a semicolon as a seperator

Thanks for any info on this.
BTW: no RAILS!
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From: Peter Hickman on 16 Apr 2010 07:11
[Note: parts of this message were removed to make it a legal post.]

Does something like this work?

require 'csv'

time = Time.now
rows =[]

(1..10).each do |x|
rows << ['row', x, 'cheese']
end

CSV.open("testfile.csv","w",:col_sep => ";") do |csv|
rows.each do |row|
csv << row
end
end

It this works then look at your data.

Also I note that the line

rows << r.join("\n")

is probably not what you want. It will turn an array into a string.

a = ['row',1,'cheese']
a.join("\n") => "row\n1\ncheese"

Are you sure you want to do this?

From: Peter Hickman on 16 Apr 2010 07:27
[Note: parts of this message were removed to make it a legal post.]

Further hacking reveals that this might be a better option to create the
file.

CSV.open("testfile.csv","w", ";") do |csv|

Note we are no longer using the :col_sep => ";" notation but we do get the ;
as a record / column separator.

From: Mitja Čebokli on 16 Apr 2010 07:57
Peter Hickman wrote:
> Further hacking reveals that this might be a better option to create the
> file.
>
> CSV.open("testfile.csv","w", ";") do |csv|
>
> Note we are no longer using the :col_sep => ";" notation but we do get
> the ;
> as a record / column separator.

Hi, thanks a lot for your help.

I have changed

while r = dataset.fetch()
rows << r.join("\n")
end

to

while r = dataset.fetch()
rows << r
end

and this now works as expected! No more problems about filling the CSV
file.

On the other hand, not using :col_sep is giving me an error:
can't convert String into Integer (TypeError)

Maybe the formatting of the line is wrong?

One more question on this matter.
How do I extract/use the table columns from the select file or if used
as "select *" to extract all the column names, and than use them as a
CSV header.

Thanks again helping me out, really appreciate it!

BR



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From: Mitja Čebokli on 16 Apr 2010 08:02
And one more thing :)

I have a problem, as it seems, with columns where data are numbers.
For example, row with ID number is returning me something like 0.2001E4

What's with that? Shouldn't the CSV export treat all the data coming
from DB as a string? Maybe there is a problem with wrong oci8 usage? (on
my side of course)

Thxs
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