created_at和updated_at列来自哪里？ [英] Where do the created_at and updated_at columns come from?

问题描述

由rails应用程序创建的数据库中的所有表似乎都有created_at和updated_at列。什么创造这些？

All the tables in the database created by a rails application seem to have created_at and updated_at columns. What creates these? Are they optional, or does something internal rely on them?

推荐答案

当您运行ActiveRecord迁移时，它们是默认创建的模型。 ActiveRecord会在您分别创建或更新模型实例（从而基础数据库表行）时自动填充/更新它们。

They are created by default when you run the ActiveRecord migration for a model. ActiveRecord automatically populates/updates them when you create or update a model instance (and thus the underlying database table row) respectively.

您可以删除 t.timestamps 行。

• Ruby on Rails指南：迁移

• Ruby on Rails Guides: Migrations

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