Start with a table with one data type as string (using sqlite command line 3.6.10 or better)

sqlite> create table test (id integer, name string)
sqlite> insert into test values (1, "Jay")
sqlite> insert into test values (2, "May")

From the ruby programming interface,

irb(main):036:0> db.execute("select from test") do |row|
irb(main):037:1 puts row.to_s
irb(main):038:1> end
Amalgalite::Error: Unable to convert SQL type of string to a Ruby class

from /usr/lib/ruby/gems/1.8/gems/amalgalite-0.10.0/lib/amalgalite/type_maps/default_map.rb:99:in `result_value_of'
from /usr/lib/ruby/gems/1.8/gems/amalgalite-0.10.0/lib/amalgalite/statement.rb:291:in `next_row'
from (irb):38:in `each_with_index'
from /usr/lib/ruby/gems/1.8/gems/amalgalite-0.10.0/lib/amalgalite/statement.rb:261:in `each'
from /usr/lib/ruby/gems/1.8/gems/amalgalite-0.10.0/lib/amalgalite/statement.rb:261:in `each_with_index'
from /usr/lib/ruby/gems/1.8/gems/amalgalite-0.10.0/lib/amalgalite/statement.rb:261:in `next_row'
from /usr/lib/ruby/gems/1.8/gems/amalgalite-0.10.0/lib/amalgalite/statement.rb:247:in `each'
from /usr/lib/ruby/gems/1.8/gems/amalgalite-0.10.0/lib/amalgalite/database.rb:292:in `execute'
from (irb):36
from :0

irb(main):039:0>

The software defect seems to be in line lib/amalgalite/type_maps/default_map.rb on line 27

'string' => %w[ text char varchar character ],

Line 27 should include 'string' in the list as well and probably say

'string' => %w[ string text char varchar character ],

Although I didn't test it there is probably also a bug in line 25, which says

'float' => %w[ double real numeric decimal ],

Line 25 should include "float" in the list and it should probably say,

'float' => %w[ float double real numeric decimal ],