使用Entity Framework核心恢复原始值

Question

在我的应用程序中，我必须同步数据库和外部服务中的更改。如果保存到外部服务时出现错误，则应使用新的更新来恢复对数据库所做的更改。

1. Get entity from database:
   var entity = context.Set<MyEntity>().Include(x => x.RelatedEntity).Find(id);

2. Perform changes to database and commit:
   entity.Name = "Changed name";
   entity.Related.Status = "Approved";
   await context.SaveChangesAsync();

3. Save to the external service:
   var response = externalService.Save(entity);

4. If there is an error, revert the changes:
   if (response.StatusCode != 200)
   {
       ???
   }

如何恢复步骤 4 中的原始值？

Answer 1

您可以使用事务来回滚其中的操作。 （请参阅 Microsoft 文档：https://learn.microsoft.com/en-us/ef/core/ saving/transactions）。

示例：

using var transaction = context.Database.BeginTransaction();

// Get entity from database
var entity = context.Set<MyEntity>().Include(x => x.RelatedEntity).Find(id);

// Perform and save changes
entity.Name = "Changed name";
entity.Related.Status = "Approved";
await context.SaveChangesAsync();

// External service call
var response = externalService.Save(entity);

// Only commit the transaction when the when the external service call
// is successful. If not, the transaction will rollback when disposed.
if (response.IsSuccesStatusCode)
{
   transaction.Commit();
}