有没有办法一次插入多个记录而不是一次插入?
我有一个非常丑陋的耙子任务,正在做以下事情…
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…
该create方法也将数组作为参数。
create
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,它仍然对每个条目执行一个SQL查询,而不是单个SQL查询。它效率更高,因为它只需要在后台创建一个activerecord对象。
如果要同时从同一客户端插入许多行,请使用带有多个VALUES列表的INSERT语句一次插入几行。这比使用单独的单行INSERT语句要快得多(某些情况下要快很多倍)。如果要将数据添加到非空表,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相同的)