我如何进行Rails迁移和Rails种子

Question

我想通过此postgresql查询进行Rails迁移和Rails种子。我该怎么办？

DROP TABLE IF EXISTS grid_light;
  CREATE TABLE grid_light AS
  SELECT DISTINCT g.ogc_fid AS id, g.geog4326 AS geog
  FROM grid g, tracks t
  WHERE t.path_buff_geog && g.geog4326 AND ST_Intersects(t.path_buff_geog, g.geog4326);

Answer 1

您应该创建一个rake任务（exp：在您的lib / task中创建grids.rake）

namespace :grids do
  desc 'explain your rake here'
  task create_grid: :environment do
    drop_sql_cmd = <<-SQL
      DROP TABLE IF EXISTS grid_light;
    SQL

    create_sql_cmd = <<-SQL
      CREATE TABLE grid_light AS
      SELECT DISTINCT g.ogc_fid AS id, g.geog4326 AS geog
      FROM grid g, tracks t
      WHERE t.path_buff_geog && g.geog4326 AND ST_Intersects(t.path_buff_geog, g.geog4326);
    SQL
    ActiveRecord::Base.transaction do
      ActiveRecord::Base.connection.execute(drop_sql_cmd)
      ActiveRecord::Base.connection.execute(create_sql_cmd)
    end
  end
end

并且如果叫rake为

bundle exec rake grids:create_grid