如何在实体框架中启用单独的审计表

Question

我有一个基于实体框架的数据库，其中包含一些实体/模型/表。例如Documents Model，我想在名为 DocumentChanges Model/Table 的单独表中跟踪对该表中每条记录的所有更改。

您能否指导我如何启用/告诉 EF 跟踪/审核所有更改到表在单独的表中？，而不仅仅是日期时间戳，但将每次更改的完整记录保存在单独的表中。

Answer 1

图书馆Audit.EntityFramework可以帮你做你想做的事。

您需要实现自己的DataProvider 来存储您希望格式化的数据。

例如：

void StartUp()
{
    //Setup to use your own provider to store the data
    Audit.Core.Configuration.Setup()
        .UseCustomProvider(new YourDataProvider());

    //Setup to audit EF operations only for the table Documents
    //(Your DbContext must inherit from AuditDbContext)
    Audit.EntityFramework.Configuration.Setup()
        .ForAnyContext(x => x.IncludeEntityObjects())
        .UseOptIn()
            .Include<Documents>();
}

class YourDataProvider : AuditDataProvider
{
    public override object InsertEvent(AuditEvent auditEvent)
    {
        //Get some enviroment info:
        var userName = auditEvent.Environment.UserName
        //Get the complete log for the EF operation:
        var efEvent = auditEvent.GetEntityFrameworkEvent();
        foreach(var entry in efEvent.Entries)
        {
            // each entry is a modified entity (updated, deleted or inserted)
            if (entry.Action == "Update")
            {
                //You can access the column values
                var value = entry.ColumnValues["ID"];
                //...or the columns changes
                var changes = entry.Changes.Select(ch => ch.ColumnName + ": " + 
                                      ch.OriginalValue + " -> " + ch.NewValue);
            }
            //... insert into DocumentChanges table
        }
        return id;
    }
}