How to enable Seperate Audits Table in Entity Framework - entity-framework

Question

I have a Entity Framework based database with a few entities/models/table. For e.g. Documents Model, I am want to track all changes to each record in that table, in a seperate table called DocumentChanges Model/Table.
Could you please guide me on how to enable/tell EF to track/audit all changes to the table in a separate table?, not just a date time stamp, but save the full record for every change in a separate table.

Answer 1

The library Audit.EntityFramework can help you to do what you want.
You'll need to implement your own DataProvider to store the data formatted as you wish.
For example:
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;
}
}