EF AddOrUpdate Questions

Question

Is it possible to ignore a value while using AddOrUpdate?

Also, what values does it look for when matching to a value and deciding what to change. I tried reading this article, but obviously it didn't help.

Let's say I have two objects in db (I realize this isn't real code):

Obj1.fieldA == 1, Obj1.fieldB == 2, Obj1.fieldC == 5
Obj1.fieldA == 1, Obj1.fieldB == 3, Obj1.fieldC == 6

And then I try to AddOrUpdate an object that matches both:

Obj3.fieldA == 1, Obj3.fieldB == 2, Obj3.fieldC == 6

How is it going to decide which one to update, if any/both?

Edit based on comments/answers in regard to Id, which I don't specify.

var someGroup = new API.Models.Group
                {
                    Name = "Blah"
                    Organization = "Blabedy blah",
                    Description = "Blah blah"
                }

db.Groups.AddOrUpdate(someGroup);

The id property is there but automatically generated:

// Id
[Key]
public long Id { get; set; }

"Is it possible to ignore a value while using AddOrUpdate?" - I have no idea what this means. Please explain better. — D Stanley, Nov 10 '15 at 22:35
If you are asking how to handle primary/natural keys - have a look at this answer - http://stackoverflow.com/a/17719137/150342 — Colin, Nov 11 '15 at 13:15

D Stanley · Accepted Answer · 2015-11-10T22:44:52.117

2

How is it going to decide which one to update,

It will update the record with the matching primary key. For example, if the primary key is a compound key consisting of fieldA and fieldB then it will match the first records and update fieldC

edited Nov 10 '15 at 22:44

answered Nov 10 '15 at 22:35

D Stanley

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What if we never specify to PK? It's Id and automatically generated, I think this is the default for EF. – VSO Nov 10 '15 at 22:41
Then it will update the record with the matching `Id` value. – D Stanley Nov 10 '15 at 22:43
See edit please, we don't specify id when using Add or AddOrUpdate – VSO Nov 10 '15 at 22:53
Then it will insert a new record since it doesn't find one with a matching key. – D Stanley Nov 10 '15 at 22:56
Thanks for your time. – VSO Nov 12 '15 at 03:55

EF AddOrUpdate Questions

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