实体框架6（代码优先）实体版本控制和审计 [英] Entity Framework 6 (code first) entity versioning and auditing

问题描述

我正在使用Entity Framework 6.1.1与SQL Server 2008 R2。

I'm looking at using Entity Framework 6.1.1 with SQL Server 2008 R2.

目前，我正在使用代码优先的EF功能创建我的模型和数据库。我的基本用例是创建一个对特定实体的所有更改的日志（ ID 是关键列），以帮助审计人员跟踪所做的所有更改以及由谁执行的操作。例如：

Currently I'm creating my models and database using the code-first EF feature. My basic use-case is to create a journal of all changes to a particular entity (ID is the key column) to help auditors track all changes made and by whom. e.g:

|ID|Version|Created Date|Created By|Modified Date|Modified By|Modify Action| ... (rest of entity fields)
-------------------------------------------------------------------------------------------------------
| 4| 12    | 12-Mar-14  | tom      | 20-Feb-15   | jack      | Update      |
| 4| 11    | 12-Mar-14  | tom      | 14-Feb-15   | jill      | Update      |
| 4| 1     | 12-Mar-14  | tom      | 12-Mar-14   | tom       | Create      |

实体框架是否支持此类型的数据库方案？如果是这样，我如何设置我的模型/解决方案来促进这一点？

Does Entity Framework support this type of database scheme? If so, how can I set my models/solution up to facilitate this?

另一种替代方法是通过拦截所有调用 SaveChanges （）方法在$ code> DbContext 并将所有数据库更改记录到单独的审核表中，但这可能使得检索信息更具挑战性。

The other alternative I have is by intercepting all calls to the SaveChanges() method on the DbContext and log all database changes into a separate Audit table, but this might make retrieving information more challenging.

任何有关使用SQL Server和EF 6创建审计跟踪的帮助将受到青睐。

Any help on creating audit trails with SQL Server and EF 6 would be greately appreciated.

推荐答案

我使用了你提到的第二种方法，通过重载dbContext SaveChanges（）方法：

I have used the 2nd approach you mention, by overloading the dbContext SaveChanges() method:

public class MyContext : DbContext
{

 public int SaveChanges(int userId)
 {
    // Get all Added/Deleted/Modified entities (not Unmodified or Detached)
    foreach (var ent in this.ChangeTracker.Entries().Where(p => p.State ==  EntityState.Added 
    || p.State == EntityState.Deleted || p.State == EntityState.Modified))
    {

        foreach (AuditLog x in GetAuditRecordsForChange(ent, userId))
        {
            this.AuditLogs.Add(x);
        }
    }
    return base.SaveChanges();
  }
...

所以如果我要记录一个特定的实体，我只是调用重载的SaveChanges&传递一个UserId：

So if I want to log a particular entity, I just call the overloaded SaveChanges & pass in a UserId:

public void Update(StockCatalogueItem entity, int userId)
{
     _context.SaveChanges(userId);
}

我还有一个自定义 DoNotLog 属性，我用来装饰我不想记录的实体属性。没有这个，记录可以生成大量的数据，因为每个实体修改等于一个db条目。

I also have a custom DoNotLog attribute which I use to decorate the entity properties that I don't want to log. Without this, the logging could generate a huge amount of data, as each entity modification equals one db entry.

[DoNotLog]
public int CreatedBy { get; set; }

GetAuditRecordsForChange 任何 DoNotLog 属性，并返回保存在AuditLogs表中的列表< AuditLog>

The GetAuditRecordsForChange method does the checking for any DoNotLog properties and returns a List<AuditLog> which gets saved in the AuditLogs table:

public class AuditLog
    {
        public int Id { get; set; }
        public int CreatedBy { get; set; }
        public DateTime CreatedOn { get; set; }
        public AuditEventType EventType { get; set; }
        public string TableName { get; set; }
        public int EntityId { get; set; }
        public string ColumnName { get; set; }
        public string Controller { get; set; }
        public string Action { get; set; }
        public string IPAddress { get; set; }
        public string OriginalValue { get; set; }
        public string NewValue { get; set; }
    }

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