Flutter-如何在Sqflite中更新表结构？ [英] Flutter - How to update the table structure in Sqflite?

问题描述

我的应用程序正在生产中，我想在用户更新应用程序时管理用户数据而不会丢失其数据，我该如何使用 sqflite 来实现这一点。明确地说，我想添加一列，然后删除另一列。

My app is in production and I want to manage user data when user updates the app without loss of their data, how can I achieve this with sqflite. Explicitly I want to add a column and delete another.

推荐答案

您可能可以使用原始SQL添加列，但sqlite（因此sqflite）不支持删除列。为此，您需要执行以下操作：

You can probably add a column using raw sql, but sqlite (and thus sqflite) doesn't support dropping a column. For that you would need to do the following:

• 增加数据库版本号


• 在 onUpgrade 将旧数据库列复制到临时表中


• 删除原始表


• 创建一个使用原始表名但具有正确模式的新表


• 从临时表中复制数据


• 删除临时表

• increase the database version number
• in onUpgrade copy the old database columns to a temporary table
• delete the original table
• create a new table using the original table name but with the right schema
• copy the data from the temp table
• delete the temp table

对不起，这不是一个完整的答案，但这是我在您遇到的情况下要走的方向。

Sorry, this isn't a full answer, but it is the direction I would go if I were in your situation.

这篇关于Flutter-如何在Sqflite中更新表结构？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！