If a row already exists, update it; otherwise, insert logic using Entity Framework.

c# entity-framework

Question

Does anyone have suggestions on the most efficient way to implement "update row if it exists else insert" logic using Entity Framework?

1
177
4/5/2011 8:06:21 PM

Accepted Answer

If you are working with attached object (object loaded from the same instance of the context) you can simply use:

if (context.ObjectStateManager.GetObjectStateEntry(myEntity).State == EntityState.Detached)
{
    context.MyEntities.AddObject(myEntity);
}

// Attached object tracks modifications automatically

context.SaveChanges();

If you can use any knowledge about the object's key you can use something like this:

if (myEntity.Id != 0)
{
    context.MyEntities.Attach(myEntity);
    context.ObjectStateManager.ChangeObjectState(myEntity, EntityState.Modified);
}
else
{
    context.MyEntities.AddObject(myEntity);
}

context.SaveChanges();

If you can't decide existance of the object by its Id you must exectue lookup query:

var id = myEntity.Id;
if (context.MyEntities.Any(e => e.Id == id))
{
    context.MyEntities.Attach(myEntity);
    context.ObjectStateManager.ChangeObjectState(myEntity, EntityState.Modified);
}
else
{
    context.MyEntities.AddObject(myEntity);
}

context.SaveChanges();
173
4/5/2011 9:29:45 PM

Popular Answer

As of Entity Framework 4.3, there is an AddOrUpdate method at namespace System.Data.Entity.Migrations:

public static void AddOrUpdate<TEntity>(
    this IDbSet<TEntity> set,
    params TEntity[] entities
)
where TEntity : class

which by the doc:

Adds or updates entities by key when SaveChanges is called. Equivalent to an "upsert" operation from database terminology. This method can be useful when seeding data using Migrations.


To answer the comment by @Smashing1978, I will paste relevant parts from link provided by @Colin

The job of AddOrUpdate is to ensure that you don’t create duplicates when you seed data during development.

First, it will execute a query in your database looking for a record where whatever you supplied as a key (first parameter) matches the mapped column value (or values) supplied in the AddOrUpdate. So this is a little loosey-goosey for matching but perfectly fine for seeding design time data.

More importantly, if a match is found then the update will update all and null out any that weren’t in your AddOrUpdate.

That said, I have a situation where I am pulling data from an external service and inserting or updating existing values by primary key (and my local data for consumers is read-only) - been using AddOrUpdate in production for more than 6 months now and so far no problems.



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