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使用Ruby DBI模块
原本的DBI模块的安装教程:
1.安装
首先,我是使用mysql进行测试的,你的机器上需要安装mysql数据库。
然后执行:
gem install mysql
到rubyforge下载ruby-DBI,解压后cd到目录运行如下命令:
ruby setup.rb config --with=dbi,dbd_mysql
ruby setup.rb setup
ruby setup.rb install
完整的setup命令参数参考DBI的doc
2.完整例子
DBI是一类似于ODBC的开发式的统一的数据库编程接口,结构层次上可以分为两层:
1.Database Interface——数据库接口层,与数据库无关,提供与数据库无关的标准接口
2.Database Driver——数据库驱动,与数据库相关
DBI也是很简单易用的,一个完整的使用例子,对于初学者可能有点帮助:- require 'dbi'
- begin
- #连接数据库
- dbh=DBI.connect("DBI:Mysql:dbi_test:localhost","root","")
-
- dbh.columns("simple").each do |h|
- p h
- end
- #示范3种事务处理方式
- #手动commit
- dbh["AutoCommit"]=false
- 1.upto(10) do |i|
- sql = "insert into simple (name, author) VALUES (?, ?)"
- dbh.do(sql, "Song #{i}", "#{i}")
- end
- dbh.commit
-
- #使用transaction方法
- dbh.transaction do |dbh|
- 1.upto(10) do |i|
- sql = "insert into simple (name, author) VALUES (?, ?)"
- dbh.do(sql, "Song #{i}", "#{i}")
- end
- end
-
- #使用SQL语句
- dbh.do("SET AUTOCOMMIT=0")
- dbh.do("BEGIN")
- dbh["AutoCommit"]=false
- dbh.do("UPDATE simple set name='test' where id='1'")
- dbh.do("COMMIT")
-
- #查询
- sth=dbh.execute("select count(id) from simple")
- puts "bookCount:#{sth.fetch[0]}"
- sth.finish
- begin
- sth=dbh.prepare("select * from simple")
- sth.execute
- while row=sth.fetch do
- p row
- end
- sth.finish
- rescue
- end
-
- #上面这段查询可以改写为:
- #dbh.select_all("select * from simple") do |row|
- # p row
- #end
复制代码 #使用工具类输出xml格式结果集以及测量查询时间- sql="select * from simple"
- mesuretime=DBI::Utils::measure do
- sth=dbh.execute(sql)
- end
- puts "SQL:#{sql}"
- puts "Time:#{mesuretime}"
- rows=sth.fetch_all
- col_names=sth.column_names
- sth.finish
- puts DBI::Utils::XMLFormatter.table(rows)
-
- dbh.do("delete from simple")
- rescue DBI::DatabaseError=>e
- puts "error code:#{e.err}"
- puts "Error message:#{e.errstr}"
- ensure
- dbh.disconnect if dbh
- end
复制代码 出现问题:
但是每次我执行第一步的时候就会出现 config: unknown option --with=dbi,dbd_mysql Try 'ruby setup.rb --help' for detailed usage.
原因分析:
这是由于dbi版本问题造成的。
因此新版本的安装方式如下:
一般方法是:下载dbi(tar.gz或zip格式),CMD下切换到解压的目录,使用以下命令:- ruby setup.rb config (或ruby setup.rb config --with=dbi,dbd_mysql)
- ruby setup.rb setup
- ruby setup.rb install
复制代码 报错:
ir- b(main):001:0> require 'dbi'
- LoadError: no such file to load -- deprecated
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from C:/MyProgramFiles/Ruby192/lib/ruby/site_ruby/1.9.1/dbi.rb:48:in `<t
- op (required)>'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from (irb):1
- from C:/MyProgramFiles/Ruby192/bin/irb:12:in `<main>'
- irb(main):002:0>
复制代码 这个问题比较简单,只要安装一个deprecated包,于是我下载了deprecated-3.0.0.gem,安装之后还是报错。- irb(main):001:0> require 'dbi'
- NoMethodError: undefined method `deprecate' for DBI::Date:Class
- from C:/MyProgramFiles/Ruby192/lib/ruby/site_ruby/1.9.1/dbi/utils/date.r
- b:57:in `<class:Date>'
- from C:/MyProgramFiles/Ruby192/lib/ruby/site_ruby/1.9.1/dbi/utils/date.r
- b:7:in `<module:DBI>'
- from C:/MyProgramFiles/Ruby192/lib/ruby/site_ruby/1.9.1/dbi/utils/date.r
- b:1:in `<top (required)>'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from C:/MyProgramFiles/Ruby192/lib/ruby/site_ruby/1.9.1/dbi/utils.rb:56:
- in `<top (required)>'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from C:/MyProgramFiles/Ruby192/lib/ruby/site_ruby/1.9.1/dbi.rb:50:in `<t
- op (required)>'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from (irb):1
- from C:/MyProgramFiles/Ruby192/bin/irb:12:in `<main>'
- irb(main):002:0>
复制代码 再次Google,居然是deprecated-3.0.0.gem太新了!换成deprecated-2.0.1.gem就可以了。- irb(main):001:0> require 'dbi'
- => true
- irb(main):002:0>
复制代码 这个问题还是比较容易解决的,不过要是出现如下问题就不好解决了:- <internal:lib/rubygems/custom_require>:29:in `require': no such file to load -- parsedate (LoadError)
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from c:/Program Files (x86)/RailsInstaller/Ruby1.9.2/lib/ruby/site_ruby/1.9.1/dbi/sql.rb:9:in `<module:DBI>'
- from c:/Program Files (x86)/RailsInstaller/Ruby1.9.2/lib/ruby/site_ruby/1.9.1/dbi/sql.rb:7:in `<top (required)>'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from c:/Program Files (x86)/RailsInstaller/Ruby1.9.2/lib/ruby/site_ruby/1.9.1/dbi.rb:37:in `<top (required)>'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from <internal:lib/rubygems/custom_require>:29:in `require'
- from E:/Program/Eclipse/RubyTest/dbi.rb:1:in `<main>'
复制代码 经过查询之后,才发现原来parsedate在ruby1.9.2中已经被废除了,现在使用的是date。因此这个版本问题真的是没有办法进行解决啦。我现在正在考虑要不要把ruby降级来解决这个问题。尝试中,后面如果解决了会进行更新。
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