Railsで、DBを作成しようとしました。
$ rake db:create
(in /home/user/railsapp)
!!! The bundled mysql.rb driver has been removed from Rails 2.2. Please install the mysql gem and try again: gem install mysql.
rake aborted!
no such file to load -- mysql

Rails 2.2.2でMySQL使うにはドライバを更新しないといけないみたいですよ・・ - てーげー探訪

Rails 2.2.2でMySQL使うにはドライバを更新しないといけないみたいですよ・・
を参考に
# cd /usr/local/lib/ruby/gems/1.8/gems/mysql-2.7

ruby extconf.rb  --with-mysql-config=/opt/local/bin/mysql_config5

extconf.rb:1: command not found: /opt/local/bin/mysql_config5 --cflags
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
        --with-opt-dir
        --without-opt-dir
        --with-opt-include
        --without-opt-include=${opt-dir}/include
        --with-opt-lib
        --without-opt-lib=${opt-dir}/lib
        --with-make-prog
        --without-make-prog
        --srcdir=.
        --curdir
        --ruby=/usr/local/bin/ruby
        --with-mysql-config
ダメでした。
以前の記憶からひらめいて、mysql-develをインストール。
# yum install mysql-devel
Loading "fastestmirror" plugin
Loading mirror speeds from cached hostfile
 * base: www.ftp.ne.jp
 * updates: www.ftp.ne.jp
 * addons: www.ftp.ne.jp
 * extras: www.ftp.ne.jp
Setting up Install Process
Parsing package install arguments
Resolving Dependencies
--> Running transaction check
---> Package mysql-devel.i386 0:5.0.45-7.el5 set to be updated
---> Package mysql-devel.x86_64 0:5.0.45-7.el5 set to be updated
--> Finished Dependency Resolution

Dependencies Resolved

=============================================================================
 Package                 Arch       Version          Repository        Size
=============================================================================
Installing:
 mysql-devel             i386       5.0.45-7.el5     base              2.4 M
 mysql-devel             x86_64     5.0.45-7.el5     base              2.4 M

Transaction Summary
=============================================================================
Install      2 Package(s)
Update       0 Package(s)
Remove       0 Package(s)

Total download size: 4.8 M
Is this ok [y/N]: y
Downloading Packages:
(1/2): mysql-devel-5.0.45 100% |=========================| 2.4 MB    00:04
(2/2): mysql-devel-5.0.45 100% |=========================| 2.4 MB    00:04
Running rpm_check_debug
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing: mysql-devel                  ######################### [1/2]
  Installing: mysql-devel                  ######################### [2/2]

Installed: mysql-devel.i386 0:5.0.45-7.el5 mysql-devel.x86_64 0:5.0.45-7.el5
Complete!
で、configurationオプションを参考に以下のように実行
#gem install mysql -- --with-mysql-config=/usr/bin/mysql_config

Building native extensions.  This could take a while...
Successfully installed mysql-2.7
1 gem installed

そして、再度、
$ rake db:create
(in /home/user/railsapp)
今度は、オッケーでした!!。