Csharp/CSharp Tutorial/LINQ/DataSet

LINQ to DataSet

using System;
using System.Collections.Generic;
using System.Linq;
using System.Data;            
using System.Data.SqlClient; 
using System.Data.Linq;      
using System.Data.rumon;
using System.Text;
    class Program
    {
        static void Main(string[] args)
        {
            SqlConnection thisConnection = new SqlConnection(
                @"Data Source=.\SQLEXPRESS;" +
                @"AttachDbFilename="NORTHWND.MDF";" +
                @"Integrated Security=True;Connect Timeout=30;User Instance=true");
            SqlDataAdapter thisAdapter = new SqlDataAdapter("SELECT CustomerID, CompanyName FROM Customers", thisConnection);
            SqlCommandBuilder thisBuilder = new SqlCommandBuilder(thisAdapter);
            DataSet thisDataSet = new DataSet();
            SqlDataAdapter custAdapter = new SqlDataAdapter("SELECT * FROM Customers", thisConnection);
            SqlDataAdapter orderAdapter = new SqlDataAdapter("SELECT * FROM Orders", thisConnection);
            custAdapter.Fill(thisDataSet, "Customers");
            orderAdapter.Fill(thisDataSet, "Orders");
            DataRelation custOrderRel = thisDataSet.Relations.Add("CustOrders",
                 thisDataSet.Tables["Customers"].Columns["CustomerID"],
                 thisDataSet.Tables["Orders"].Columns["CustomerID"]);
            var customers = thisDataSet.Tables["Customers"].AsEnumerable();
            var orders = thisDataSet.Tables["Orders"].AsEnumerable();
            var preferredCustomers = from c in customers
                where c.GetChildRows("CustOrders").Length > 10
                select c;
            foreach (var customer in preferredCustomers)
            {
                Console.WriteLine(customer.GetChildRows("CustOrders").Length);
                Console.WriteLine(customer["CustomerID"]);
            }
            thisConnection.Close();
        }
    }

Linq To Sql

using System;
using System.Linq;
using System.Data.Linq;
using System.Data.Linq.Mapping;
    [Table]
    public class Customers
    {
        [Column]
        public string customerId;
        [Column]
        public string companyName;
        [Column]
        public string city;
        [Column]
        public string country;
    }
    class LinqToSql
    {
        static void Main(string[] args)
        {
            string connString = @"server = .\sqlexpress;integrated security = true;database = northwind";
            DataContext db = new DataContext(connString);
            Table<Customers> customers = db.GetTable<Customers>();
            var custs = from c in customers where c.country == "USA" orderby c.city select c;
            foreach (var c in custs)
                Console.WriteLine(
                   "{0}, {1}, {2}, {3}",
                   c.customerId,
                   c.rupanyName,
                   c.city,
                   c.country
                );
        }
    }

Simple Linq to SQL

using System;
using System.Data.Linq;
using System.Data.Linq.Mapping;
using System.Linq;
    [Table(Name="Sales.Customer")]
    public class Customer
    {
        [Column] public string FirstName    { get; set; }
        [Column] public string LastName     { get; set; }
        [Column] public string EmailAddress { get; set; }
        public override string ToString()
        {
            return string.Format("{0} {1}\nEmail:   {2}",FirstName, LastName, EmailAddress);
        }
    }
    public class Tester
    {
        static void Main()
        {
            DataContext db = new DataContext(@"Data Source=.\SqlExpress;Initial Catalog=AdventureWorks;Integrated Security=True");
            Table<Customer> customers = db.GetTable<Customer>();
            var query = from customer in customers where customer.FirstName == "D" select customer;
            foreach(var c in query)
                Console.WriteLine(c.ToString());
        }
    }