# Ruby-odbc -- Strange Chaning of Special Character in Result

**URL:** <https://www.ruby-forum.com/t/ruby-odbc-strange-chaning-of-special-character-in-result/51946>\
**Category:** Ruby\
**Created:** [January 9, 2006, 4:09pm UTC](https://www.ruby-forum.com/t/ruby-odbc-strange-chaning-of-special-character-in-result/51946 "2006-01-09T16:09:02Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![ben](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/df788c/32.png) [@ben](https://www.ruby-forum.com/u/ben)\
**Post date:** [January 9, 2006, 4:09pm UTC](https://www.ruby-forum.com/t/ruby-odbc-strange-chaning-of-special-character-in-result/51946/1 "2006-01-09T16:09:02Z")

</div>

Hi,

Some strange behind-the-scenes character conversion appears to be  
occuring when fetching ASCII code 150 using ruby-odbc. This is  
exempilfied by the script below. It _should_ return identical data for  
both selects. However, it does not. When char(150) is selected, the  
ASCII character code 63 is returned. Not good. ☹

Server information:  
Linux version 2.6.12-10-686-smp (buildd@terranova) (gcc version 3.4.5  
20050809 (prerelease) (Ubuntu 3.4.4-6ubuntu8)) #1 SMP Fri Nov 18  
12:27:41 UTC 2005  
ruby 1.8.3 (2005-06-23) [i486-linux]

What do y’all think?

Thanks,  
Ben

=== script ===  
require ‘odbc’

connection=ODBC.connect(‘dsn’,‘username’,‘password’)

sql1 = ‘select char(150)’  
puts “Selecting the ASCII character for char code 150 [#{sql1}]”  
puts “=” \* 70  
results1 = connection.run(sql1)  
results\_array1 = results1.fetch\_all  
puts “Character: \t” + results\_array1[0][0]  
print “Char Code: \t”  
print results\_array1[0][0][0].to\_i  
puts

puts

sql2 = ‘select ascii(char(150))’  
puts “Selecting the numeric code for char(150) [#{sql2}]”  
puts “=” \* 70  
results2 = connection.run(sql2)  
results\_array2 = results2.fetch\_all  
print “Char Code: \t”  
print results\_array2[0][0]  
puts  
puts “Character: \t” + results\_array2[0][0].chr

# === Output === Selecting the ASCII character for char code 150 [select char(150)]

Character: ? \<---- should be blank like the below  
Char Code: 63 \<---- should be 150

# Selecting the numeric code for char(150) [select ascii(char(150))]

Char Code: 150  
Character: (blank) \<---- because the shell window won’t display  
the em dash

---

<div class="post-metadata">

**Author:** ![ben](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/df788c/32.png) [@ben](https://www.ruby-forum.com/u/ben)\
**Post date:** [January 9, 2006, 11:52pm UTC](https://www.ruby-forum.com/t/ruby-odbc-strange-chaning-of-special-character-in-result/51946/2 "2006-01-09T23:52:57Z")

</div>

I tested your script on my system (actually I rewrote portions of it,  
as shown below), and when the output was sent to bash standard output  
all  
extended-ascii characters where output as a simple dash ("-"). This  
apparently is either a limitation of bash or cygwin.

Then I sent the output to a file called “out”, and I was able to see  
the extended-ascii characters.

od -c out

=\> 0001500 h a r a c t e r : \t 226 \n C h  
a

shows char(150) as 226, which is octal for 150, so that’s right.

Gvim shows the accented-u character properly once I set my encoding  
for extended-ascii (8-bit):

:set enc=cp437

The output of the test script as viewed in gvim (cp437 encoding):

# Selecting the ASCII character for char code 97 [select char(97)]

Character: a  
Char Code: 97  
result array: [[“a”]]

# Selecting the numeric code for char(97) [select ascii(char(97))]

Char Code: 97  
Character: a

# Selecting the ASCII character for char code 150 [select char(150)]

Character: û  
Char Code: 150  
result array: [["\226"]]

# Selecting the numeric code for char(150) [select ascii(char(150))]

Char Code: 150  
Character: û

ûù

# test script =======================================================

#!/usr/bin/ruby

require ‘odbc’

DNS=‘test’  
USR=‘odbcuser’  
PWD=‘super\_secret\_password’

connection=ODBC.connect(DNS,USR,PWD)

a = [97,150]

File.open(‘out’, ‘wb’) do |wbf|  
a.each { |c|  
wbf.puts  
sql1 = “select char(#{c})”  
wbf.puts “Selecting the ASCII character for char code #{c} [#{sql1}]”  
wbf.puts “=” \* 70  
results1 = connection.run(sql1)  
results\_array1 = results1.fetch\_all  
wbf.puts “Character: \t” + results\_array1[0][0]  
wbf.print “Char Code: \t”  
wbf.puts results\_array1[0][0][0].to\_i  
wbf.puts “result array: #{results\_array1.inspect}”  
wbf.puts

```
results1.drop

sql2 = "select ascii(char(#{c}))"
wbf.puts "Selecting the numeric code for char(#{c}) [#{sql2}]"
wbf.puts "=" * 70
results2 = connection.run(sql2)
results_array2 = results2.fetch_all
wbf.print "Char Code: \t"
wbf.print results_array2[0][0]
wbf.puts
wbf.puts "Character: \t" + results_array2[0][0].chr
wbf.puts

results2.drop

```

}  
wbf.puts “\226\227” #little test  
end

connection.disconnect

* * *

I didn’t get any warnings when compiling ruby-odbc, but I was using gcc  
3.4.4.  
I also ran the ruby-odbc tests and they were all fine.

So, in conclusion, at least on cygwin/win xp pro sp2, ruby-odbc seems to  
work swell.  
I recommend sending your output to a file and doing something similar to  
what I’ve done to see exactly what’s being sent back from odbc instead  
of relying on a (possibly lying) terminal. It would also have been  
helpful to  
know which database [and version] you used.

-lv

---

<div class="post-metadata">

**Author:** ![ben](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/df788c/32.png) [@ben](https://www.ruby-forum.com/u/ben)\
**Post date:** [January 11, 2006, 6:00pm UTC](https://www.ruby-forum.com/t/ruby-odbc-strange-chaning-of-special-character-in-result/51946/3 "2006-01-11T18:00:56Z")

</div>

Hi Lou,

Thanks for your reply.

> I recommend sending your output to a file and doing something similar to  
> what I’ve done to see exactly what’s being sent back from odbc instead  
> of relying on a (possibly lying) terminal. It would also have been helpful to  
> know which database [and version] you used.

I’m not concerned about if/how the terminal outputs the character–that  
output was for illustration only. The “Char Code” line is the one of  
interest. In my original script, shouldn’t the terminal output this  
number correctly?

Running your script and looking at the output file still shows a char  
code of 63 for select char(150) and 150 for select ascii(char(150)).  
☹

I’m using MS Sql Server 7.0, FreeTDS and Ruby-ODBC.

> I didn’t get any warnings when compiling ruby-odbc, but I was using gcc 34.4.

Christian (author of ruby-odbc) communicated with me about this and  
provided a solution to the signedness difference error. Thank you,  
Christian!

Ben

---

<div class="post-metadata">

**Author:** ![ben](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/df788c/32.png) [@ben](https://www.ruby-forum.com/u/ben)\
**Post date:** [January 11, 2006, 7:21pm UTC](https://www.ruby-forum.com/t/ruby-odbc-strange-chaning-of-special-character-in-result/51946/4 "2006-01-11T19:21:28Z")

</div>

I’m not familiar with FreeTDS, but Google says that some versions of  
FreeTDS  
have problems with extended ascii:

[[freetds] Openldap segfaults in freetds code.](http://lists.ibiblio.org/pipermail/freetds/2003q2/012800.html)  
[[freetds] FreeTDS performance](http://lists.ibiblio.org/pipermail/freetds/2003q2/012791.html)  
[http://www.phpbuilder.com/board/history/topic.php/10268497-1.html](http://www.phpbuilder.com/board/history/topic.php/10268497-1.html)

so it appears that if you are running FreeTDS .61, extended ascii is  
broken.

Your FreeTDS log should show the error. What does your log say?  
[[http://www.freetds.org/userguide/logging.htm](http://www.freetds.org/userguide/logging.htm)]

```
On retrieving data from the server, FreeTDS substitutes an ASCII '?'
in the character's place, and emits a warning message stating that
some characters could not be converted.
[http://www.freetds.org/userguide/nonwestern.htm]

```

This explains why ‘150’ is mysteriously being converted to 63 (i.e.  
‘?’).