ruby-on-rails - 将 ROR 中的整数更改为 bigint

Question

我需要将表整数更改为 BIGINT 我正在使用 RoR 和 SQLLite。

如何通过命令行将现有表字段从 Int 修改为 BigInt？

Answer 1

您可以通过迁移来做到这一点。这是文档的链接:http://edgeguides.rubyonrails.org/active_record_migrations.html

基本上，您需要运行:

rails g migration change_your_column_to_bigint

并将此代码添加到迁移新迁移文件中:

def up
  execute <<-SQL
    ALTER TABLE ip_to_countries
    ALTER COLUMN your_column TYPE bigint USING your_column::bigint
  SQL
end

郑重声明，我从这里偷了这个:How do I change a string column into a bigint? ，但没有将其标记为重复，因为它涉及转换字符串列。

现在我收到此错误

SQLite3::SQLException: near "ALTER": syntax error:     ALTER TABLE posts
    ALTER COLUMN mileage TYPE bigint USING mileage::bigint
C:/Sites/jeepjig/db/migrate/20150315145856_change_mileage_to_bigint.rb:3:in `change'
C:in `migrate'
ActiveRecord::StatementInvalid: SQLite3::SQLException: near "ALTER": syntax error:     ALTER TABL
    ALTER COLUMN mileage TYPE bigint USING mileage::bigint
C:/Sites/jeepjig/db/migrate/20150315145856_change_mileage_to_bigint.rb:3:in `change'
C:in `migrate'
SQLite3::SQLException: near "ALTER": syntax error
C:/Sites/jeepjig/db/migrate/20150315145856_change_mileage_to_bigint.rb:3:in `change'
C:in `migrate'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)

运行后

class ChangeMileageToBigint < ActiveRecord::Migration
  def change
  execute <<-SQL
    ALTER TABLE posts
    ALTER COLUMN mileage TYPE bigint USING mileage::bigint
  SQL
end
end