CODEWITHSUNDEEP
c#.netentity-frameworksystem.data.sqlite
saurabh
saurabh

Reputation: 540

Find object for given primary key in entity framework

I have a table "Customer" and its corresponding ORMapping Entity Customer in entity framework and I want to find an object corresponding to a given primary key. Something like customerObject.getObjectByID() instead of a lambda expression or query.

Upvotes: 10

Views: 24182

Answers (5)

Gary Huckabone
Gary Huckabone

Reputation: 412

If you have a composite key, build an object array and pass it to Find(). Eg:

try
{
    RECORD rec; // ie, your entity definition of a record (row)
    Object[] onePK = { id, s0, s1 };
    rec = YourEntities.RECORDs.Find(onePK);
    if (rec == null)
    {
        // handle the record-not-found situation
    }
}
catch (SystemException sex)
{
    string error = sex.Message;
}

Upvotes: 2

Dave Jellison
Dave Jellison

Reputation: 933

"instead of lambda expression or query"

customerobject.Find(id);

More specifically: 

var myDbSetTableEntity = context.MyDbSetTableEntity.Find(object key1, object key2)

Upvotes: 8

user3892038
user3892038

Reputation: 31

for composite keys: customerobject.Find(key1, key2, key3)

what is order you specify the keys, assuming they are all strings ?

Upvotes: 1

Icarus
Icarus

Reputation: 63970

var Customer = from c in datacontext.Customer
               where c.CustomerID == your_key
               select c;

That's assuming your customer table has a CustomerID column and that is the primary key.

Using DbSet's Find method:

Customer customer= db.Customer.Find(your_key);

Using a lambda expression:

 var customer= dataContext.Customer.Where(x=>x.CustomerID==your_key).FirstOrDefault();

Upvotes: 12

Henk Holterman
Henk Holterman

Reputation: 273864

The most compact way:

var myCustomer = myContext.Customers.SingleOrDefault(c => c.Id == wantedId);

wich is basically short-form for 

myContext.Customers.Where(c => c.Id == wantedId).SingleOrDefault();

Other candidate selection methods are Single(), First() and FirstOrDefault()

Upvotes: 3

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