我已設定了我的数据库, 我想在模型中新增一个字段, 在表格中新增一个列, 是否有办法在不丢失全部数据的情况下做到这一点? 通常, 如果您删除 DB, 它将会自动重建所有数据, 但我不想丢失数据。 我将 SQL 服务器2008 用作数据库 。
您需要使用 EF 迁移来在数据库中添加新栏目。 您可以阅读更多关于 EF 迁移 < a href="http://msdn.microsoft.com/ en- US/ data/jj554735" rel = "noreferr" >这里 和 < a href="http://msdn.microsoft.com/ en- US/ data/jj591621, rel="noreferr"。
如果您首先使用代码, 我总是在这样的情况下手工将列添加到数据库中。 不幸的是, 没有简单的方法可以自动使用代码一的增量模式更新 。
例如,《EF Code First s 自己的差错之一甚至指定人工更新为最佳选择:
支持“ 您的上下文” 的模型自数据库创建以来已经改变。 要么是手动删除/ 更新数据库, 要么是用 IDatabase Intializer 来调用数据库 SetIntializer 。 例如, DroftCreateDatabaseIfModelChanges 战略将自动删除和重新创建数据库, 并选用新数据进行种子 。
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