LINQ

LINQ - LANGUAGE INTEGRATED QUERY

ENVIRONMENT:

1. Create DataClasses1.dbml.


2. Create a database Test with table test which has Id (integer, PK) and Name (varchar(10)).


3. Create a stored procedure GetDatas


4. Using server explorer connect to database Test and add the table "test" and Stored proceure "getDatas" in the DataClasses1.dbml

* Once the dbml file is created system automatically creates a class "DataClasses1DataContext"

EXAMPLES

1. Retrieve data from Table test
   

   using (DataClasses1DataContext dc = new DataClasses1DataContext())
   IEnumerable t = from b in dc.tests select b; //where b.name.StartsWith("Ra")
   foreach (test t1 in t)
   {
   Console.WriteLine(t1.name);
   }
   }
   
   

2. retrieve data from Stored Procedure
   using (DataClasses1DataContext dc = new
   {
   var t = from b in dc.getDatas() select b;
   foreach (var t1 in t)
   {
   Console.WriteLine(t1.name);
   }
   }
   
   
3. Insert in to Table test
   
   using (DataClasses1DataContext dc = new DataClasses1DataContext())
   {
   test d = new test();
   d.name = 'n';
   dc.duplicates.InsertOnSubmit(d);
   dc.SubmitChanges();
   }
   
   
4. Updation
   using (DataClasses1DataContext dc = new DataClasses1DataContext())
   {
   IEnumerable t = from b in dc.tests select b; //where b.name.StartsWith("Ra")
   //Update Table
   test t2 = t.Single((a) => a.ID == 1);
   t2.name = "updated";
   dc.SubmitChanges();
   }
   
   

* If the datable doesn't contain primary key , you will not able to do insertion , updation and deletion . To
achieve this add attribute to any one of the column for that table in DataClasses1DataContext class as follows
[Column(Storage = "_id", DbType = "Int", IsPrimaryKey = true)]
public System.Nullable id
{
get
{
return this._id;
}
set
{
if ((this._id != value))
{
this._id = value;
}
}
}