The environment:

Mac OS X 10.6.4

$ ruby -v
ruby 1.8.7 (2009-06-12 patchlevel 174) [universal-darwin10.0]

$ rails -v
Rails 2.3.9

$ mysql --version
mysql  Ver 14.14 Distrib 5.1.51, for apple-darwin10.3.0 (i386) using readline 5.1

$ gem environment
RubyGems Environment:
  - RUBYGEMS VERSION: 1.3.7
  - RUBY VERSION: 1.8.7 (2009-06-12 patchlevel 174) [universal-darwin10.0]
  - INSTALLATION DIRECTORY: /usr/local/lib/ruby/gems/1.8
  - RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
  - EXECUTABLE DIRECTORY: /usr/local/lib/ruby/gems/1.8/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - universal-darwin-10
  - GEM PATHS:
     - /usr/local/lib/ruby/gems/1.8
     - /Users/ethan/.gem/ruby/1.8
     - /Library/Ruby/Gems/1.8
     - /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
     - :sources => ["http://gemcutter.org"]
  - REMOTE SOURCES:
     - http://gemcutter.org

Installed MySQL by downloading mysql-5.1.51-osx10.6-x86.dmg from mysql.com.

Installed mysql gem like this:

$ sudo gem install mysql --no-rdoc --no-ri -- \
--with-mysql-dir=/usr/local/mysql --with-mysql-lib=/usr/local/mysql/lib \
--with-mysql-include=/usr/local/mysql/include
Building native extensions.  This could take a while...
Successfully installed mysql-2.8.1
1 gem installed

$ gem list -l | grep mysql
mysql (2.8.1)

MySQL works:

$ mysql -u root
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1
Server version: 5.1.51 MySQL Community Server (GPL)

Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
This software comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to modify and redistribute it under the GPL v2 license

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

The problem:

$ rake db:create
(in /Users/.../project/employeedata)
Couldn't create database for {"encoding"=>"utf8", "adapter"=>"mysql", "username"=>开发者_JAVA百科"root", "database"=>"employeedata_development", "password"=>nil, "socket"=>"/tmp/mysql.sock"}, charset: utf8, collation: utf8_unicode_ci (if you set the charset manually, make sure you have a matching collation)

Question:

How can I get the mysql gem to work?

I am wondering if this discussion could help you: rake db:create - collation issues

Seems like the same problem as yours.

I am wondering if the mysql gem actually compiled OK for you. If the link above does not help, can you tell me what happens when you do:

./script/console

and then trying to access some of your models?