Rails 2 AR#first method

The first method ignores that id in all database drivers. first just adds a limit 1 to the query - so in your case, it looks like in your mysql database, the first Person record happened to have an id of 3. Here's what I get in both mysql and sqlite3:

>> Post.create!
=> #<Post id: 1, title: nil, created_at: "2010-06-19 02:09:11", updated_at: "2010-06-19 02:09:11">
>> Post.create!
=> #<Post id: 2, title: nil, created_at: "2010-06-19 02:09:14", updated_at: "2010-06-19 02:09:14">
>> Post.create!
=> #<Post id: 3, title: nil, created_at: "2010-06-19 02:09:17", updated_at: "2010-06-19 02:09:17">
>> Post.first
=> #<Post id: 1, title: nil, created_at: "2010-06-19 02:09:11", updated_at: "2010-06-19 02:09:11">
>> Post.first 3 # => the "3" is totally ignored
=> #<Post id: 1, title: nil, created_at: "2010-06-19 02:09:11", updated_at: "2010-06-19 02:09:11">

If you want to get the record by id, just use find:

Person.find params[:id]

If you want to find the first with some conditions, pass the conditions:

Person.first :conditions => {:id => 3}