如何在rails上的ruby中复制mySQL数据库？

Question

我们正在制作一个Ruby On Rails webapp,每个客户都可以获得自己的数据库.
在我们的网站上填写表格后,需要创建数据库.

我们有一个模板数据库,其中包含我们需要复制的所有表和列.我怎么能以编程方式从ruby on rails上做到这一点？

Answer 1

我不确定你的意思,但你可以使用ruby的命令行功能来转储模板数据库,创建一个新数据库并使用mysqldump程序重新导入它:

> mysqldump -uroot -proot templateDB > dump.sql
> mysql -uroot -proot --execute="CREATE DATABASE newDB"
> mysql -uroot -proot newDB < dump.sql

以下是从Ruby调用命令行选项的很好的描述.

Answer 2

从任何控制器,您可以定义以下方法.

 def copy_template_database
        template_name = "customerdb1" # Database to copy from
        new_name = "temp" #database to create & copy to

        #connect to template database to copy.  Note that this will override any previous
        #connections for all Models that inherit from ActiveRecord::Base
        ActiveRecord::Base.establish_connection({:adapter => "mysql", :database => template_name, :host => "olddev",
        :username => "root", :password => "password" })

        sql_connection = ActiveRecord::Base.connection 
        sql_connection.execute("CREATE DATABASE #{new_name} CHARACTER SET latin1 COLLATE latin1_general_ci")
        tables = sql_connection.select_all("Show Tables")
        #the results are an array of hashes, ie:
        # [{"table_from_customerdb1" => "customers"},{"table_from_customerdb1" => "employees},...]
        table_names = Array.new
        tables.each { |hash| hash.each_value { |name| table_names << name }}

        table_names.each { |name| 
            sql_connection.execute("CREATE TABLE #{new_name}.#{name} LIKE #{template_name}.#{name}")
            sql_connection.execute("INSERT INTO #{new_name}.#{name} SELECT * FROM #{template_name}.#{name}")
        }
        #This statement is optional.  It connects ActiveRecord to the new database
        ActiveRecord::Base.establish_connection({:adapter => "mysql", :database => new_name, :host => "olddev",
        :username => "root", :password => "password" })
    end

请注意,我不确定这是否会保持foriegn密钥的完整性.我认为这很大程度上取决于模板数据库的创建方式.