Behaviour of saving an entity

[Edward]

Hi,

I have a context with Visitors and I'm saving a new one and then retrieve it like:

string name = "Rico " + guid;
var b = new OADemo.Customer();
b.Lastname = name;
context.Add(b);

var sb = context.Customer.FirstOrDefault(x => x.Lastname == achternaam);

sb will return null.  I'm adding the new one to the context and then i'm quering this context so I thought it would find this newly inserted guy. This is not the case. Do I always need to do SaveChanges first?

Thanks!

[Viktor Zhivkov]

Hi Edward,

Yes, It is required to call SaveChanges() before querying newly created instances. Executing a query the way you have posted issues a database query. Since the changes are not yet committed to the database, the internal data reader does not include the new record in the results.

If you insist on skipping the SaveChanges() method call, you can use FlushChanges() which will persist the changes to the database (this includes inserted, updated and deleted records), but leaves the database transaction uncommitted. Later you have to additionally commit or rollback the transaction. This approach gives greater control over the database operations, but introduces s bit of complexity.

Here is our documentation about the Context API related to transactions and persistence. Check the SaveChanges, FlushChanges, ClearChanges and Refresh sections.

If you have any additional questions about the Context API or OpenAccess in general do not hesitate to contact us again.

Kind regards,
Viktor Zhivkov
the Telerik team

[Edward]

pretty neat