我有一个工作解决方案Soft Delete in Entity Framework Code First可能有所帮助。
关键是,您可以为您希望能够软删除的每个模型添加一个鉴别器。在第一个代码是这样完成的:
modelBuilder.Entity<Foo>().Map(m => m.Requires("IsDeleted").HasValue(false));
这使得它无形的背景下,因此您可以使用SQL做删除。
如果这是在数据库中你的“条件映射”的同义的第一,然后修改SQL一个办法就是从那里覆盖的SaveChanges和运行SQL:用于Get Table Name explained here
public override int SaveChanges()
{
foreach (var entry in ChangeTracker.Entries()
.Where(p => p.State == EntityState.Deleted
&& p.Entity is ModelBase))//I do have a base class for entities with a single
//"ID" property - all my entities derive from this,
//but you could use ISoftDelete here
SoftDelete(entry);
return base.SaveChanges();
}
private void SoftDelete(DbEntityEntry entry)
{
var e = entry.Entity as ModelBase;
string tableName = GetTableName(e.GetType());
Database.ExecuteSqlCommand(
String.Format("UPDATE {0} SET IsDeleted = 1 WHERE ID = @id", tableName)
, new SqlParameter("id", e.ID));
//Marking it Unchanged prevents the hard delete
//entry.State = EntityState.Unchanged;
//So does setting it to Detached:
//And that is what EF does when it deletes an item
//http://msdn.microsoft.com/en-us/data/jj592676.aspx
entry.State = EntityState.Detached;
}
方法那是我过去这样做的方式。可能与EF5中的数据库优先方法无关,但我现在已经开始使用存储过程。 EF6 Code First在迁移文件中生成CreateStoredProcedure
调用。我将它们替换为this.CreateDeleteProcedure("dbo.Foo_Delete", "[dbo].[Foos]");
- 这是对我自己的扩展方法的调用:
public static class MigrationExtensions
{
internal static string DeleteSqlFormat
{
//I also hard delete anything deleted more than a day ago in the same table
get { return "DELETE FROM {0} WHERE IsDeleted = 1 AND DATEADD(DAY, 1, DeletedAt) < GETUTCDATE(); UPDATE {0} SET IsDeleted = 1, DeletedAt = GETUTCDATE() WHERE ID = @ID;"; }
}
internal static void CreateDeleteProcedure(this DbMigration migration, string procName, string tableName)
{
migration.CreateStoredProcedure(
procName,
p => new
{
ID = p.Int(),
},
body:
string.Format(MigrationExtensions.DeleteSqlFormat, tableName)
);
}
}
+1非常好的解决方案。 –
这就是我一直在寻找的词,“软删除”。是的,这对于代码来说似乎是一个很好的解决方案。很可能,我将在存储过程中创建一个动态查询,并在edmx中使用存储过程映射,并将我创建的存储过程映射到Delete。所以当我在上下文中调用Delete时,它会自动调用我自动映射的Delete存储过程。 – Amila
令人印象深刻的是,在寻找工作解决方案后,我找到了一个。在让GetTableName工作时有一些小问题,你在另一篇文章中发布的版本需要一些小的调整来编译。但这并没有改变这个事实,即这种软删除方法的确像一种魅力。 –