Rails Rake Task放置表并从CSV导入 [英] Rails Rake Task drop table and import from csv

问题描述

我试图编写一个rake任务以删除表并从csv重新填充它。目的是按计划从另一个系统获取数据，并使用rails应用程序管理界面中的按钮导入新数据。这些新数据将覆盖表中的旧数据。

I am trying to write a rake task to drop a table and repopulate it from a csv. The intention is to obtain the data from another system on a schedule, and use a button in the admin interface of my rails application to import the new data. This new data will overwrite the old data in the table.

我不确定如何执行此操作，因此正在处理rake任务。到目前为止，我可以导入新数据，但是我不知道如何首先删除表格。到目前为止，我的代码是：

I am not exactly sure how to do this so am playing around with rake tasks. So far I can import the new data but I can't figure out how to drop the table first. My code so far is:

namespace :csvimportproducts do

  desc "Import Products CSV Data."
  task :import_products_csv_data => :environment do

    ActiveRecord::Migration.drop_table products

    require 'csv'
    csv_file_path = '/home/jay/workspace/db/import_tables/products.csv'
    CSV.foreach(csv_file_path) do |row|
      p = Product.create!({
          :product_id => row[0],
          :product_name => row[1],
        }
      )
    end
  end
end

此刻我正在存储本地csv文件，但稍后打算由管理员将其作为csv文件上传。

At the moment I am storing the csv files locally but intend later to have it uploaded by the administrator as a csv file.

有什么想法吗？我的错误是：

Any ideas? My error is:

rake aborted!                                                                                                                                                      
undefined local variable or method `products' for main:Object                                                                                                      
/lib/tasks/import_products_csv.rake:6:in `block (2 levels) in <top (required)>'                                                               
Tasks: TOP => csvimportproducts:import_products_csv_data

推荐答案

尝试通过运行自定义sql命令：

Try by truncating the table by running a custom sql command:

namespace :csvimportproducts do

  desc "Import Products CSV Data."
  task :import_products_csv_data => :environment do

    ActiveRecord::Base.connection.execute("TRUNCATE TABLE products")

    require 'csv'
    csv_file_path = '/home/jay/workspace/db/import_tables/products.csv'
    CSV.foreach(csv_file_path) do |row|
      p = Product.create!({
          :product_id => row[0],
          :product_name => row[1],
        }
      )
    end
  end
end

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