LINQ to SQL Storing query results in a variable

Question

For example I am searching for a specific persons ID and I want to store that ID to a local variable or instance variable. How do I retrieve Query results and stores them in a int Variable with LINQ to SQL? Assuming we have this query

from user in dbo.DoctorsName
where doctorsName  = "Foo Bar"
select DOC_ID;

what is DOC_ID? I really dont understand what you want? do you want to get the results from DB and assign them to local variables? — Jayanga, Feb 23 '12 at 07:01
DOC_ID is simply a an ID, I want to retrieve an ID where the doctors name is "Foo Bar" — user962206, Feb 23 '12 at 07:07

score 6 · Accepted Answer · answered Feb 23 '12 at 07:00

6

You can use FirstOrDefault() like this:

var results = from user in dbo.DoctorsName
              where user.doctorsName  == "Foo Bar"
              select user;

string personName = results.FirstOrDefault().Name;

answered Feb 23 '12 at 07:00

Mahmoud Gamal

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That's it? how would I execute the query? there's no insertOnSubmit? What if i am looking for a table ID? not a String? – user962206 Feb 23 '12 at 07:07
@user962206, Why did you need `insertOnSubmit()`?? and you can select any of the `user` properties as well like `int ID = results.FirstOrDefault().ID` this will give you one value for the one row selected. – Mahmoud Gamal Feb 23 '12 at 07:10
That's the code I need? no more? that's just it? no more executeQuery(results) like in java? – user962206 Feb 23 '12 at 07:12
@user962206, no more, just like this. – Mahmoud Gamal Feb 23 '12 at 07:13

score 0 · Answer 2 · answered Feb 23 '12 at 07:00

0

This should help.

var name = dbo.DoctorsName.Where(item => item.doctorsName = "Foo Bar").Select(item => item.Name).FirstOrDefault();

If there are no records for your condition then using FirstOrDefault() can throw an exception. For this you can try using -

var namelist = dbo.DoctorsName.Where(item => item.doctorsName = "Foo Bar").Select(item => item.Name);

If(namelist.Count() > 0)
   var name = namelist.Fisrt();

answered Feb 23 '12 at 07:00

pavanred

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`FirstOrDefault` in ur first code snippet will not throw exception because u are selecting `item.Name` which is of type string. if there is no matching record, it will simply return null which is `default` for string type – Muhammad Adeel Zahid Feb 23 '12 at 07:22

score 0 · Answer 3 · answered Feb 23 '12 at 07:03

Similar to this:

var ticketDepartment = from t in dt_tickets.AsEnumerable()
                       where t.Field<string>("MID") == mid
                       select new { department = t.Field<string>("Department") };

and now you have your variable in ticketDepartment.department

LINQ to SQL Storing query results in a variable

3 Answers3