mysql - 使用 ruby on rails 活动记录插入多条记录

Question

有没有办法一次插入多个记录而不是一个？

我有一个非常丑陋的 rake 任务，它正在执行以下操作......

        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2000-03-07", :party => row[45], :participate => participated(row[45]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2000-11-07", :party => row[46], :participate => participated(row[46])) 
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "SP", :election => "2000-05-08", :party => row[47], :participate => participated(row[47]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2001-11-06", :party => row[48], :participate => participated(row[48]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2002-05-07", :party => row[49], :participate => participated(row[49]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2002-11-05", :party => row[50], :participate => participated(row[50]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "SP", :election => "2003-05-06", :party => row[51], :participate => participated(row[51]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2003-11-04", :party => row[52], :participate => participated(row[52]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2004-03-02", :party => row[53], :participate => participated(row[53]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2004-11-02", :party => row[54], :participate => participated(row[54]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "SP", :election => "2005-02-08", :party => row[55], :participate => participated(row[55]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2005-05-03", :party => row[56], :participate => participated(row[56]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2005-09-13", :party => row[57], :participate => participated(row[56]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2005-11-08", :party => row[58], :participate => participated(row[58]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "SP", :election => "2006-02-07", :party => row[59], :participate => participated(row[59]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2006-05-02", :party => row[60], :participate => participated(row[60]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2006-11-07", :party => row[61], :participate => participated(row[61]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2007-05-08", :party => row[62], :participate => participated(row[62]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2007-09-11", :party => row[63], :participate => participated(row[63]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2007-11-06", :party => row[64], :participate => participated(row[64]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2007-11-06", :party => row[65], :participate => participated(row[65]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2007-12-11", :party => row[66], :participate => participated(row[66]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2008-03-04", :party => row[67], :participate => participated(row[67]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2008-10-14", :party => row[68], :participate => participated(row[68]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2008-11-04", :party => row[69], :participate => participated(row[69]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2008-11-18", :party => row[70], :participate => participated(row[70]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2009-05-05", :party => row[71], :participate => participated(row[71]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2009-09-08", :party => row[72], :participate => participated(row[72]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2009-09-15", :party => row[73], :participate => participated(row[73]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2009-09-29", :party => row[74], :participate => participated(row[74]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2009-11-03", :party => row[75], :participate => participated(row[75]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2010-05-04", :party => row[76], :participate => participated(row[76]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2010-07-13", :party => row[77], :participate => participated(row[77]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2010-09-07", :party => row[78], :participate => participated(row[78]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2010-11-02", :party => row[79], :participate => participated(row[79]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2011-05-03", :party => row[80], :participate => participated(row[80]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2011-09-13", :party => row[81], :participate => participated(row[81]))
        VoteRecord.create(:prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2011-11-08", :party => row[82], :participate => participated(row[82]))

这必须非常低效，并且必须有更好的方法......

score 67 · Accepted Answer

该create方法还接受一个数组作为参数。

VoteRecord.create(
  [
    { :prospect_id => prospect.id, :state => "OH", :election_type => "GE", :election => "2011-11-08", :party => row[82], :participate => participated(row[82]) },
    { :prospect_id => prospect.id, :state => "OH", :election_type => "PR", :election => "2011-09-13", :party => row[81], :participate => participated(row[81]) }
    ...
  ]
)

但是，这仍然对每个条目执行一个 SQL 查询，而不是单个 SQL 查询。它更有效，因为它只需要在后台创建一个 activerecord 对象。

如果您同时从同一个客户端插入多行，请使用带有多个 VALUES 列表的 INSERT 语句一次插入多行。这比使用单独的单行 INSERT 语句要快得多（在某些情况下快很多倍）。如果要向非空表添加数据，则可以调整 bulk_insert_buffer_size 变量以使数据插入更快。请参见第 5.1.3 节，“服务器系统变量”。

从mysql页面（但我想其他数据库应该是一样的）

score 20 · Accepted Answer

不幸的是，这在 Rails 中是不可能的。

然而，对于 Rails 3.x， activerecord-import是一个很棒的 gem，它import为你的模型类添加了一个方法，并且作为一个单一的 SQL 插入语句完成了你想要的事情。

score 13 · Accepted Answer

Rails 6 现在支持这个开箱即用：

https://blog.bigbinary.com/2019/04/15/bulk-insert-support-in-rails-6.html

可以使用新添加的方法执行批量插入：insert_all、insert_all！和 upsert_all。

score -7 · Accepted Answer

您可以将 ActiveRecord 语句包装在ActiveRecord::Base.transaction：

ActiveRecord::Base.transaction do 
  1000.times { Post.create(options) } 
end

有关其他技术，请参阅这篇文章。

mysql - 使用 ruby​​ on rails 活动记录插入多条记录

4 回答 4

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mysql - 使用 ruby on rails 活动记录插入多条记录