Entity Framework returns stale data when selecting the whole entity but up to date when selecting just a field

Question

My Entity Framework backed project returns stale data when selecting the whole entity but the data is up to date when selecting just a field from the entity.

Here are the steps:

1. Query via EF/LINQ:

   var e  = context.myEntity.First(x=>x.ID==ID);
   string n = context.myEntity.Where(x=>x.ID==ID).Select(x=>x.Name).First();
   

2. Update the Name field in the DB via SQL directly

3. Then Query again via EF/LINQ:

   var e  = context.myEntity.First(x=>x.ID==ID);
   string n = context.myEntity.Where(x=>x.ID==ID).Select(x=>x.Name).First();
   

e.Name is the previous value but n is up to date.

We are re-using the same context between calls.

Using the SQL profiler, I can confirm that even when the data is stale the SQL query from EF occurs.

What can cause this?

Answer 1

The data is cached in the Context. Ideally your context should have a short lifetime (a unit of work, for example) to prevent this behaviour becoming a problem, but if you need to force an update from the database, set the MergeOption to OverwriteChanges

context.MergeOption = MergeOption.OverwriteChanges