如何在Rails迁移中创建此特定的PostGres索引? [英] How do I create this specific PostGres index in a Rails migration?

问题描述

我正在使用Rails 4.2.7和PostGres 9.5.我正在尝试在表上创建trqm索引(以方便进行LIKE搜索)，所以我创建了此迁移

I’m using Rails 4.2.7 and PostGres 9.5. I’m trying to create a trqm index on my table (to facilitate LIKE searches) so I created this migration

class AddTrqmIndexOnRaceTimes < ActiveRecord::Migration
  def change
    CREATE INDEX my_object_times_name_gin_trgm_idx ON my_object_times USING gin (name gin_trgm_ops);
  end
end

当我运行"rake db:migrate"时，这会导致以下错误……

This results in the below error when I run "rake db:migrate" …

StandardError: An error has occurred, this and all later migrations canceled:

undefined local variable or method `gin_trgm_ops' for #<AddTrqmIndexOnRaceTimes:0x007fdc34b40600>
/Users/mikeb/.rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:664:in `block in method_missing'
/Users/mikeb/.rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:634:in `block in say_with_time'
/Users/mikeb/.rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:634:in `say_with_time'
/Users/mikeb/.rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:654:in `method_missing'
/Users/mikeb/Documents/workspace/runtrax/db/migrate/20161012185951_add_trqm_index_on_my_object_times.rb:3:in `change'
/Users/mikeb/.rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:608:in `exec_migration'
/Users/mikeb/.rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:592:in `block (2 levels) in migrate'
/Users/mikeb/.rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:591:in `block in migrate'
/Users/mikeb/.rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/connection_pool.rb:292:in `with_connection'
/Users/mikeb/.rvm/gems/ruby-2.3.0/gems/activerecord-4.2.7.1/lib/active_record/migration.rb:590:in `migrate'

在Rails迁移中创建此索引的正确方法是什么?

What’s the right way to create this index in a Rails migration?

推荐答案

您需要对您的代码进行一些更改.将SQL查询包装在 execute 中.

ou need to make slight changes to your code. Wrap the sql query in execute.

class AddTrqmIndexOnRaceTimes < ActiveRecord::Migration
  def change
    execute "CREATE INDEX my_object_times_name_gin_trgm_idx ON my_object_times USING gin (name gin_trgm_ops);"
  end
end

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