I am currently working on learning Ruby. I have always been a Perl fanatic, but a new build framework that my company is using requires me to use Ruby. Whee, a chance to learn something new! I am a geek.
Background
In Perl, I never used the DBI due to the issues that I had with getting it installed in a couple of AIX environments, and the inability in some client environments to install the DBI. However, with Ruby I don’t see that being an issue at this point, so I’m trying to make use of the tools designed for interacting with the database.
Little did I suspect that this decision would lead me to a 6-hour oddessy of simply trying to connect to the database. Granted, part of that time was due to my own ignorance of Ruby, and it won’t take a tenth as much time for future setups.
Installing the IBM_DB Gem
I started out wrong by simply installing the gem without looking for instructions. I found: sqllib/ruby64/ibm_db-2.5.11.gem, and simply used: gem install ~db2inst2/sqllib/ruby64/ibm_db-2.5.11.gem as root. Don’t make my mistake – use the proper instructions on installing the gem. That also happens to be by one of my favorite authors on technical blogging topics.
After I fixed my install mistake, a friend helped me figure out that version of the driver that comes with DB2 10.1 Fixpack 3 is not compatible with the version of Ruby I was using (2.0.0). The gem that was packaged with db2 was 2.5.11, and I needed 2.5.12. Of course, it did not tell me this, it simply did this when I tried to connect:
-bash-4.1$ irb
2.0.0-p353 :001 > require 'ibm_db'
=> true
2.0.0-p353 :002 > conn = IBM_DB.connect("WC042D02", "", "")
TypeError: no implicit conversion from nil to integer
from (irb):2:in `connect'
from (irb):2
from /usr/local/rvm/rubies/ruby-2.0.0-p353/bin/irb:12:in `'
Nice useful error message, that.
After determining that I needed to update the gem, I tried it and got this error:
[root@server ~]# gem update ibm_db Updating installed gems Updating ibm_db Building native extensions. This could take a while... ERROR: Error installing ibm_db: ERROR: Failed to build gem native extension. /usr/local/rvm/rubies/ruby-2.0.0-p353/bin/ruby extconf.rb Detected 64-bit Ruby checking for SQLConnect() in -ldb2... yes checking for gil_release_version... no checking for unicode_support_version... no creating Makefile extconf.rb:114:in `libpathflag': Use RbConfig instead of obsolete and deprecated Config. extconf.rb:114:in `libpathflag': Use RbConfig instead of obsolete and deprecated Config. make "DESTDIR=" compiling ibm_db.c In file included from ibm_db.c:27: ruby_ibm_db_cli.h:52:21: error: sqlcli1.h: No such file or directory In file included from ibm_db.c:27: ruby_ibm_db_cli.h:56: error: expected specifier-qualifier-list before ‘SQLSMALLINT’
After much digging around with the help of my friend, we found that /opt/IBM/db2/V10.1/include was nearly empty. The reason it was empty was because I had not installed the application development tools component when I installed db2. I believe db2_install includes this component, but a typical install with db2setup does not. See my blog entry on how to install a component after the rest of db2 is installed if you, too, need to add this component in.
After installing that component and updating my instances, I tried again to update the gem and got what I needed this time:
[root@server]# . /db2home/db2inst2/sqllib/db2profile [root@server]# echo $IBM_DB_INCLUDE /db2home/db2inst2/sqllib/include [root@server]# echo $IBM_DB_LIB /db2home/db2inst2/sqllib/lib [root@server]# gem update ibm_db Updating installed gems Updating ibm_db Building native extensions. This could take a while... Successfully installed ibm_db-2.5.12 Parsing documentation for ibm_db-2.5.12 unable to convert "\xB0" from ASCII-8BIT to UTF-8 for lib/ibm_db.so, skipping Installing ri documentation for ibm_db-2.5.12 Installing darkfish documentation for ibm_db-2.5.12 Gems updated: ibm_db
Finally, I again tested a simple database connection:
[db2inst2@server]$ irb
2.0.0p353 :001 > require 'ibm_db'
=> true
2.0.0p353 :002 > conn = IBM_DB.connect("SAMPLE","","")
=> #
2.0.0p353 :003 > quit
That is what a successful connection looks like.
Executing a Statement
A week later, when I finally got around to attempting to execute a statement, I got this error:
2.0.0-p353 :003 > stmt=IBM_DB.exec(conn, "select * from syscat.bufferpools") irb: symbol lookup error: /usr/local/rvm/gems/ruby-2.0.0-p353/gems/ibm_db-2.5.12/lib/ibm_db.so: undefined symbol: rb_str2cstr
With some research on http://rubyforge.org/), I figured out that in the week between getting the connection working and trying the statement, a new version of the gem had been released, that fixed this exact issue. I updated again:
[root@server ~]# . /db2home/db2inst2/sqllib/db2profile [root@server ~]# export IBM_DB_DIR=/db2home/db2inst2/sqllib [root@server ~]# gem update ibm_db Updating installed gems Updating ibm_db Building native extensions. This could take a while... Successfully installed ibm_db-2.5.14 Parsing documentation for ibm_db-2.5.14 unable to convert "\xD1" from ASCII-8BIT to UTF-8 for lib/ibm_db.so, skipping Installing ri documentation for ibm_db-2.5.14 Installing darkfish documentation for ibm_db-2.5.14 Gems updated: ibm_db
After that, I was able to execute a statement. Phew, lot of work just to get to that point.
A big thanks to @idbjorh for his extensive help with this issue. If you don’t already, you should be listening to his podcast – The Whole Package Cache
Look for more Ruby/DB2 articles from me. I write about what I do, and I expect to be working on this pretty intensively.