Rails 改变现有数据库视图的迁移

Question

我有一个名为 my_view 的视图，它是我使用以下迁移创建的。

class CreateMyView < ActiveRecord::Migration
  def change
    execute <<-SQL
      drop view if exists my_view
    SQL

    execute <<-SQL
      CREATE OR REPLACE VIEW my_view AS 
      SELECT 
        t1.wfs_id,
        t1.step_id,
        t1.status,
        t1.applied_by,
        t2.created_at,
        t2.is_wfs_end,
        t2.app_status AS flowstep
       FROM table1 t1
         JOIN table2 t2 ON t1.wfs_id = t2.wfs_id
      WHERE t1.del_flag = false;
    SQL
  end
end

现在我需要另一个字段，比如 table1 中的 my_new_field 在 my_view 中可用。但我不知道如何为此编写迁移。非常感谢任何帮助。谢谢

Answer 1

简单地重新创建视图怎么样：

class ChangeMyView < ActiveRecord::Migration   
  def change
    execute <<-SQL
      drop view if exists my_view
    SQL

    execute <<-SQL
      CREATE OR REPLACE VIEW my_view AS 
      SELECT 
        t1.wfs_id,
        t1.step_id,
        t1.status,
        t1.applied_by,
        t1.my_new_field,
        t2.created_at,
        t2.is_wfs_end,
        t2.app_status AS flowstep
      FROM table1 t1
        JOIN table2 t2 ON t1.wfs_id = t2.wfs_id
      WHERE t1.del_flag = false;
   SQL 
  end

end

Answer 2

scenic gem（来自 Thoughtbot）将对您管理视图有很大帮助！

Rails 改变现有数据库视图的迁移

Rails migration for altering existing database view

ruby-on-rails

ruby-on-rails-4

database-migration

database-view