我正在尝试让 Postgre DBI 与 Ruby 一起使用，但还没有找到权威的答案，但我希望在这里能找到帮助......
这是产生错误的代码：
#!/usr/bin/ruby
require 'pg'
$maxwidth=12
conn = PGconn.connect("localhost", 5432, '', '', "testdb", "caseyr", "genesrule")
###### DROP ANY EXISTING rocks TABLE ######
begin
res = conn.exec("SELECT id FROM rocks;")
rescue # rocks table doesn't exist -- this is legitimate
else # rocks table exists, so delete it
puts 'DELETING rocks...'
res = conn.exec("DROP TABLE rocks;")
end
###### CREATE AND POPULATE rocks TABLE ######
begin
res = conn.exec("CREATE TABLE rocks (id serial, rockname char(20));")
res = conn.exec("INSERT INTO ROCKS (rockname) values ('Diamond');")
res = conn.exec("INSERT INTO ROCKS (rockname) values ('Ruby');")
res = conn.exec("INSERT INTO ROCKS (rockname) values ('Emerald');")
rescue Pgconn::PGError => e
puts "Error creating and filling rocks table."
puts "Error code: #{e.err}"
puts "Error message: #{e.errstr}"
conn.close() if conn
end
这是错误消息：
ruby testRocks.rb
DELETING rocks...
NOTICE: CREATE TABLE will create implicit sequence "rocks_id_seq" for serial column "rocks.id"
testRocks.rb:35: uninitialized constant Pgconn (NameError)
我不确定要使用的正确类名；Pgconn是一个猜测。
但进一步的测试表明这个简单的测试也失败了：
#!/usr/bin/ruby
require 'postgres'
失败了：
ruby basictest.rb
basictest.rb:2:in `require': no such file to load -- postgres (LoadError)
from basictest.rb:2
现在，我想我已经安装了 postgres gem：
gem list | grep post
postgres (0.7.9.2008.01.28)
postgres-pr (0.6.3)
所以，我不知所措
- 我是否安装了正确的 Postgres 驱动程序和 DBI？
- 为什么我上面的第一个测试程序失败了？