LINQ综合学习大全

public class User

{

    private int _id;

    private string _name;

    private int _age;

    public int Id

    {

        get { return _id; }

        set { _id = value; }

    }

    public string Name

    {

        get { return _name; }

        set { _name = value; }

    }

    public int Age

    {

        get { return _age; }

        set { _age = value; }

    }

}

public class User

{

    public int Id { get; set; }

    public string Name { get; set; }

    public int Age { get; set; }

}

var i = 5;//int

var j = 23.56;//double

var k = "C Sharp";//string

var x;//错误

var y = null;//错误

var z = { 1, 2, 3 };//错误

var p1 = new { Id = 1, Name = "YJingLee", Age = 22 };//属性也不需要申明

var p2 = new { Id = 2, Name = "XieQing", Age = 25 };

p1 = p2;//p1,p2结构相同，可以互相赋值

public class SomeType

{

    public int Id { get; set; }

    public string Name { get; set; }

    public int Age { get; set; }

}

var intArray = new[] { 2, 3, 5, 6 };

var strArray = new[] { "Hello", "World" };

var anonymousTypeArray = new[]

{

    new { Name = "YJingLee", Age = 22 },

    new { Name = "XieQing", Age = 25 }

};

var a = intArray[0];

var b = strArray[0];

var c = anonymousTypeArray[1].Name;

User user = new User();

user.Id = 1;

user.Name = "YJingLee";

user.Age = 22;

User user = new User { Id = 1, Name = "YJingLee", Age = 22 };

List<User> user = new List<User>{

    new User{Id=1,Name="YJingLee",Age=22},

    new User{Id=2,Name="XieQing",Age=25},

};

User user = new User { Id = 1, Name = "YJingLee", Age = 22 };

User user2 = new User { Id = 2, Name = "XieQing", Age = 25 };

user = user2;

User user = new User

{

    Id = 1,

    Name = "YJingLee",

    Age = 22,

    Address = new Address

    {

        City = "NanJing",

        Zip = 21000

    }

};

List<int> num = new List<int> { 0, 1, 2, 6, 7, 8, 9 };

public class User

{

    public int Id { get; set; }

    public string Name { get; set; }

    public int Age { get; set; }

    public string Read()

    {

        return "Id:" + Id + "姓名:" + Name + "年龄:" + Age;

    }

}

var user = new { Id = 1, Name = "YJingLee", Age = 22 };

var str = user.Read();

var email = "leeyongjing@gmail.com";

if (EmailValidator.IsValid(email))

{

    Response.Write("YJingLee提示:这是一个正确的邮件地址");

}

if (email.IsValidEmailAddress())

{

    Response.Write("YJingLee提示:这是一个正确的邮件地址");

}

public static class Extensions//静态类

{

    public static bool IsValidEmailAddress(this string s)

    //静态方法和this

    {

        Regex regex = new Regex(@"^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$");

        return regex.IsMatch(s);

    }

}

var inString = list.FindAll(delegate(string s)

{ return s.Indexof("YJingLee") >= 0; });

var inString = list.FindAll(s => s.Indexof("YJingLee") >= 0);

(x, y) => x * y;//多参数，隐式类型=>表达式

x => x * 10;//单参数，隐式类型=>表达式

x => { return x * 10; }; //单参数，隐式类型=>语句块

(int x) => x * 10;//单参数，显式类型=>表达式

(int x) => { return x * 10; };//单参数，显式类型=>语句块

() => Console.WriteLine(); //无参数

List<User> user = new List<User>{

    new User{Id=1,Name="YJingLee",Age=22},

    new User{Id=2,Name="XieQing",Age=25},

};

//获取特定人时所用的过滤条件，p参数属于User类型

var results = user.Where(p => p.Name == "YJingLee").ToList();

//用User对象的Age值计算平均年龄

var average = user.Average(p => p.Age);

var resultsdelegate = user.Where(delegate(User p)

{

    return p.Name == "YJingLee";// 返回一个布尔值

});

var averagedelegate = user.Average(delegate(User p)

{

    return p.Age;

});

Expression<Func<int, bool>> filter = n => (n * 3) < 5;

BinaryExpression lt = (BinaryExpression)filter.Body;

BinaryExpression mult = (BinaryExpression)lt.Left;

ParameterExpression en = (ParameterExpression)mult.Left;

ConstantExpression three = (ConstantExpression)mult.Right;

ConstantExpression five = (ConstantExpression)lt.Right;

var One = filter.Compile();

Console.WriteLine("Result: {0},{1}", One(5), One(1));

Console.WriteLine("({0} ({1} {2} {3}) {4})", lt.NodeType,

         mult.NodeType, en.Name, three.Value, five.Value);

var q =

    from c in db.Customers

    where c.City == "London"

    select c;

var q =

    from e in db.Employees

    where e.HireDate >= new DateTime(1994, 1, 1)

    select e;

var q =

    from p in db.Products

    where p.UnitsInStock <= p.ReorderLevel && !p.Discontinued

    select p;

var q =

    from p in db.Products

    where p.UnitPrice > 10m || p.Discontinued

    select p;

var q =

    db.Products.Where(p=>p.UnitPrice > 10m).Where(p=>p.Discontinued);

Shipper shipper = db.Shippers.First();

Customer cust = db.Customers.First(c => c.CustomerID == "BONAP");

Order ord = db.Orders.First(o => o.Freight > 10.00M);

var q =

    from c in db.Customers

    select c.ContactName;

var q =

    from c in db.Customers

    select new {c.ContactName, c.Phone};

var q =

    from e in db.Employees

    select new

    {

        Name = e.FirstName + " " + e.LastName,

        Phone = e.HomePhone

    };

var q =

    from p in db.Products

    select new

    {

        p.ProductID,

        HalfPrice = p.UnitPrice / 2

    };

var q =

    from p in db.Products

    select new

    {

        p.ProductName,

        Availability =

        p.UnitsInStock - p.UnitsOnOrder < 0 ?

        "Out Of Stock" : "In Stock"

    };

var q =

    from e in db.Employees

    select new Name

    {

        FirstName = e.FirstName,

        LastName = e.LastName

    };

var q =

    from c in db.Customers

    where c.City == "London"

    select c.ContactName;

var q =

    from c in db.Customers

    select new {

        c.CustomerID,

        CompanyInfo = new {c.CompanyName, c.City, c.Country},

        ContactInfo = new {c.ContactName, c.ContactTitle}

    };

var q =

    from o in db.Orders

    select new {

        o.OrderID,

        DiscountedProducts =

            from od in o.OrderDetails

            where od.Discount > 0.0

            select od,

        FreeShippingDiscount = o.Freight

    };

var q = from c in db.Customers

         where c.Country == "UK" || c.Country == "USA"

         select new

         {

             c.CustomerID,

             c.CompanyName,

             Phone = c.Phone,

             InternationalPhone =

             PhoneNumberConverter(c.Country, c.Phone)

         };

public string PhoneNumberConverter(string Country, string Phone)

{

    Phone = Phone.Replace(" ", "").Replace(")", ")-");

    switch (Country)

    {

        case "USA":

            return "1-" + Phone;

        case "UK":

            return "44-" + Phone;

        default:

            return Phone;

    }

}

XDocument doc = new XDocument(

    new XElement("Customers", from c in db.Customers

              where c.Country == "UK" || c.Country == "USA"

              select (new XElement("Customer",

                      new XAttribute("CustomerID", c.CustomerID),

                      new XAttribute("CompanyName", c.CompanyName),

                      new XAttribute("InterationalPhone",

                       PhoneNumberConverter(c.Country, c.Phone))

                     ))));

var q = (

    from c in db.Customers

    select c.City )

    .Distinct();

var q = db.Customers.Count();

var q = db.Products.Count(p => !p.Discontinued);

var q = db.Customers.LongCount();

var q = db.Orders.Select(o => o.Freight).Sum();

var q = db.Products.Sum(p => p.UnitsOnOrder);

var q = db.Products.Select(p => p.UnitPrice).Min();

var q = db.Orders.Min(o => o.Freight);

var categories =

    from p in db.Products

    group p by p.CategoryID into g

    select new {

        CategoryID = g.Key,

        CheapestProducts =

            from p2 in g

            where p2.UnitPrice == g.Min(p3 => p3.UnitPrice)

            select p2

    };

var q = db.Employees.Select(e => e.HireDate).Max();

var q = db.Products.Max(p => p.UnitsInStock);

var categories =

    from p in db.Products

    group p by p.CategoryID into g

    select new {

        g.Key,

        MostExpensiveProducts =

            from p2 in g

            where p2.UnitPrice == g.Max(p3 => p3.UnitPrice)

            select p2

    };

var q = db.Orders.Select(o => o.Freight).Average();

var q = db.Products.Average(p => p.UnitPrice);

var categories =

    from p in db.Products

    group p by p.CategoryID into g

    select new {

        g.Key,

        ExpensiveProducts =

            from p2 in g

            where p2.UnitPrice > g.Average(p3 => p3.UnitPrice)

            select p2

    };

var q =

    from c in db.Customers

    from o in c.Orders

    where c.City == "London"

    select o;

var q =

    from p in db.Products

    where p.Supplier.Country == "USA" && p.UnitsInStock == 0

    select p;

SELECT [t0].[ProductID], [t0].[ProductName], [t0].[SupplierID],

[t0].[CategoryID],[t0].[QuantityPerUnit],[t0].[UnitPrice],

[t0].[UnitsInStock], [t0].[UnitsOnOrder],[t0].[ReorderLevel],

[t0].[Discontinued] FROM [dbo].[Products] AS [t0]

LEFT OUTER JOIN [dbo].[Suppliers] AS [t1] ON

[t1].[SupplierID] = [t0].[SupplierID]

WHERE ([t1].[Country] = @p0) AND ([t0].[UnitsInStock] = @p1)

-- @p0: Input NVarChar (Size = 3; Prec = 0; Scale = 0) [USA]

-- @p1: Input Int (Size = 0; Prec = 0; Scale = 0) [0]

var q =

    from e in db.Employees

    from et in e.EmployeeTerritories

    where e.City == "Seattle"

    select new

    {

        e.FirstName,

        e.LastName,

        et.Territory.TerritoryDescription

    };

SELECT [t0].[FirstName], [t0].[LastName], [t2].[TerritoryDescription]

FROM [dbo].[Employees] AS [t0] CROSS JOIN [dbo].[EmployeeTerritories]

AS [t1] INNER JOIN [dbo].[Territories] AS [t2] ON

[t2].[TerritoryID] = [t1].[TerritoryID]

WHERE ([t0].[City] = @p0) AND ([t1].[EmployeeID] = [t0].[EmployeeID])

-- @p0: Input NVarChar (Size = 7; Prec = 0; Scale = 0) [Seattle]

var q =

    from e1 in db.Employees

    from e2 in e1.Employees

    where e1.City == e2.City

    select new {

        FirstName1 = e1.FirstName, LastName1 = e1.LastName,

        FirstName2 = e2.FirstName, LastName2 = e2.LastName,

        e1.City

    };

SELECT [t0].[FirstName] AS [FirstName1], [t0].[LastName] AS

[LastName1],[t1].[FirstName] AS [FirstName2], [t1].[LastName] AS

[LastName2],[t0].[City] FROM [dbo].[Employees] AS [t0],

[dbo].[Employees] AS [t1] WHERE ([t0].[City] = [t1].[City]) AND

([t1].[ReportsTo] = [t0].[EmployeeID])

var q =

    from c in db.Customers

    join o in db.Orders on c.CustomerID

    equals o.CustomerID into orders

    select new

    {

        c.ContactName,

        OrderCount = orders.Count()

    };

SELECT [t0].[ContactName], (

    SELECT COUNT(*)

    FROM [dbo].[Orders] AS [t1]

    WHERE [t0].[CustomerID] = [t1].[CustomerID]

) AS [OrderCount]

FROM [dbo].[Customers] AS [t0]

var q =

    from c in db.Customers

    join o in db.Orders on c.CustomerID

    equals o.CustomerID into ords

    join e in db.Employees on c.City

    equals e.City into emps

    select new

    {

        c.ContactName,

        ords = ords.Count(),

        emps = emps.Count()

    };

SELECT [t0].[ContactName], (

    SELECT COUNT(*)

    FROM [dbo].[Orders] AS [t1]

    WHERE [t0].[CustomerID] = [t1].[CustomerID]

) AS [ords], (

SELECT COUNT(*)

    FROM [dbo].[Employees] AS [t2]

    WHERE [t0].[City] = [t2].[City]

) AS [emps]

FROM [dbo].[Customers] AS [t0]

var q =

    from e in db.Employees

    join o in db.Orders on e equals o.Employee into ords

    from o in ords.DefaultIfEmpty()

    select new

    {

        e.FirstName,

        e.LastName,

        Order = o

    };

var q =

    from c in db.Customers

    join o in db.Orders on c.CustomerID

    equals o.CustomerID into ords

    let z = c.City + c.Country

    from o in ords

    select new

    {

        c.ContactName,

        o.OrderID,

        z

    };

var q =

    from o in db.Orders

    from p in db.Products

    join d in db.OrderDetails

        on new

        {

            o.OrderID,

            p.ProductID

        } equals

            new

            {

                d.OrderID,

                d.ProductID

            }

        into details

    from d in details

    select new

    {

        o.OrderID,

        p.ProductID,

        d.UnitPrice

    };

var q =

    from o in db.Orders

    join e in db.Employees

        on o.EmployeeID equals

        (int?)e.EmployeeID into emps

    from e in emps

    select new

    {

        o.OrderID,

        e.FirstName

    };

var q =

    from e in db.Employees

    orderby e.HireDate

    select e;

var q =

    from o in db.Orders

    where o.ShipCity == "London"

    orderby o.Freight

    select o;

var q =

    from p in db.Products

    orderby p.UnitPrice descending

    select p;

var q =

    from c in db.Customers

    orderby c.City, c.ContactName

    select c;

var q =

    db.Customers

    .OrderBy(c => c.City)

    .ThenBy(c => c.ContactName).ToList();

var q =

    db.Customers

    .OrderBy(c => c.ContactName)

    .OrderBy(c => c.City).ToList();

var q =

    db.Customers

    .OrderByDescending(c => c.City)

    .ThenByDescending(c => c.ContactName).ToList();

var q =

    db.Customers

    .OrderBy(c => new

    {

        c.City,

        c.ContactName

    }).ToList();

var q =

    db.Customers

    .Select(c => new

    {

        c.City,

        c.Address

    })

    .OrderBy(c => c).ToList();

var q =

    db.Customers

    .Select(c => c.City)

    .OrderBy(c => c).ToList();

var q =

    from o in db.Orders

    where o.EmployeeID == 1

    orderby o.ShipCountry, o.Freight descending

    select o;

var q =

    from p in db.Products

    group p by p.CategoryID into g

    orderby g.Key

    select new {

        g.Key,

        MostExpensiveProducts =

            from p2 in g

            where p2.UnitPrice == g.Max(p3 => p3.UnitPrice)

            select p2

    };

var q =

    from p in db.Products

    group p by p.CategoryID into g

    select g;

var q =

    from p in db.Products

    group p by p.CategoryID;

foreach (var gp in q)

{

    if (gp.Key == 2)

    {

        foreach (var item in gp)

        {

            //do something

        }

    }

}

var q =

    from p in db.Products

    group p by p.CategoryID into g

    select new { CategoryID = g.Key, g };

foreach (var gp in q)

{

    if (gp.CategoryID == 2)

    {

        foreach (var item in gp.g)

        {

            //do something

        }

    }

}

var q =

    from p in db.Products

    group p by p.CategoryID into g

    select new {

        g.Key,

        MaxPrice = g.Max(p => p.UnitPrice)

    };

var q =

    from p in db.Products

    group p by p.CategoryID into g

    select new {

        g.Key,

        MinPrice = g.Min(p => p.UnitPrice)

    };

var q =

    from p in db.Products

    group p by p.CategoryID into g

    select new {

        g.Key,

        AveragePrice = g.Average(p => p.UnitPrice)

    };

var q =

    from p in db.Products

    group p by p.CategoryID into g

    select new {

        g.Key,

        TotalPrice = g.Sum(p => p.UnitPrice)

    };

var q =

    from p in db.Products

    group p by p.CategoryID into g

    select new {

        g.Key,

        NumProducts = g.Count()

    };

var q =

    from p in db.Products

    group p by p.CategoryID into g

    select new {

        g.Key,

        NumProducts = g.Count(p => p.Discontinued)

    };

var q =

    from p in db.Products

    group p by p.CategoryID into g

    where g.Count() >= 10

    select new {

        g.Key,

        ProductCount = g.Count()

    };

var categories =

    from p in db.Products

    group p by new

    {

        p.CategoryID,

        p.SupplierID

    }

        into g

        select new

            {

                g.Key,

                g

            };

var categories =

    from p in db.Products

    group p by new { Criterion = p.UnitPrice > 10 } into g

    select g;

var q =

    from c in db.Customers

    where !c.Orders.Any()

    select c;

SELECT [t0].[CustomerID], [t0].[CompanyName], [t0].[ContactName],

[t0].[ContactTitle], [t0].[Address], [t0].[City], [t0].[Region],

[t0].[PostalCode], [t0].[Country], [t0].[Phone], [t0].[Fax]

FROM [dbo].[Customers] AS [t0]

WHERE NOT (EXISTS(

    SELECT NULL AS [EMPTY] FROM [dbo].[Orders] AS [t1]

    WHERE [t1].[CustomerID] = [t0].[CustomerID]

   ))

var q =

    from c in db.Categories

    where c.Products.Any(p => p.Discontinued)

    select c;

SELECT [t0].[CategoryID], [t0].[CategoryName], [t0].[Description],

[t0].[Picture] FROM [dbo].[Categories] AS [t0]

WHERE EXISTS(

    SELECT NULL AS [EMPTY] FROM [dbo].[Products] AS [t1]

    WHERE ([t1].[Discontinued] = 1) AND

    ([t1].[CategoryID] = [t0].[CategoryID])

    )

var q =

    from c in db.Customers

    where c.Orders.All(o => o.ShipCity == c.City)

    select c;

string[] customerID_Set =

    new string[] { "AROUT", "BOLID", "FISSA" };

var q = (

    from o in db.Orders

    where customerID_Set.Contains(o.CustomerID)

    select o).ToList();

var q = (

    from o in db.Orders

    where (

    new string[] { "AROUT", "BOLID", "FISSA" })

    .Contains(o.CustomerID)

    select o).ToList();

var q = (

    from o in db.Orders

    where !(

    new string[] { "AROUT", "BOLID", "FISSA" })

    .Contains(o.CustomerID)

    select o).ToList();

var order = (from o in db.Orders

             where o.OrderID == 10248

             select o).First();

var q = db.Customers.Where(p => p.Orders.Contains(order)).ToList();

foreach (var cust in q)

{

    foreach (var ord in cust.Orders)

    {

        //do something

    }

}

string[] cities =

    new string[] { "Seattle", "London", "Vancouver", "Paris" };

var q = db.Customers.Where(p=>cities.Contains(p.City)).ToList();

var q = (

         from c in db.Customers

         select c.Phone

        ).Concat(

         from c in db.Customers

         select c.Fax

        ).Concat(

         from e in db.Employees

         select e.HomePhone

        );

var q = (

         from c in db.Customers

         select new

         {

             Name = c.CompanyName,

             c.Phone

         }

        ).Concat(

         from e in db.Employees

         select new

         {

             Name = e.FirstName + " " + e.LastName,

             Phone = e.HomePhone

         }

        );

var q = (

         from c in db.Customers

         select c.Country

        ).Union(

         from e in db.Employees

         select e.Country

        );

var q = (

         from c in db.Customers

         select c.Country

        ).Intersect(

         from e in db.Employees

         select e.Country

        );

var q = (

         from c in db.Customers

         select c.Country

        ).Except(

         from e in db.Employees

         select e.Country

        );

var q = (

    from e in db.Employees

    orderby e.HireDate

    select e)

    .Take(5);

var q = (

    from p in db.Products

    orderby p.UnitPrice descending

    select p)

    .Skip(10);

var q = (

    from c in db.Customers

    orderby c.ContactName

    select c)

    .Skip(50)

    .Take(10);

var q = (

    from p in db.Products

    where p.ProductID > 50

    orderby p.ProductID

    select p)

    .Take(10);

var q = from c in db.Customers

        where SqlMethods.Like(c.CustomerID, "C%")

        select c;

var q = from c in db.Customers

        where !SqlMethods.Like(c.CustomerID, "A_O_T")

        select c;

var q = from o in db.Orders

        where SqlMethods

        .DateDiffDay(o.OrderDate, o.ShippedDate) < 10

        select o;

//1.创建compiled query

NorthwindDataContext db = new NorthwindDataContext();

var fn = CompiledQuery.Compile(

    (NorthwindDataContext db2, string city) =>

    from c in db2.Customers

    where c.City == city

    select c);

//2.查询城市为London的消费者,用LonCusts集合表示，这时可以用数据控件绑定

var LonCusts = fn(db, "London");

//3.查询城市为Seattle的消费者

var SeaCusts = fn(db, "Seattle");

NorthwindDataContext db = new NorthwindDataContext();

var newCustomer = new Customer

{

    CustomerID = "MCSFT",

    CompanyName = "Microsoft",

    ContactName = "John Doe",

    ContactTitle = "Sales Manager",

    Address = "1 Microsoft Way",

    City = "Redmond",

    Region = "WA",

    PostalCode = "98052",

    Country = "USA",

    Phone = "(425) 555-1234",

    Fax = null

};

db.Customers.InsertOnSubmit(newCustomer);

db.SubmitChanges();

var newCategory = new Category

{

    CategoryName = "Widgets",

    Description = "Widgets are the ……"

};

var newProduct = new Product

{

    ProductName = "Blue Widget",

    UnitPrice = 34.56M,

    Category = newCategory

};

db.Categories.InsertOnSubmit(newCategory);

db.SubmitChanges();

var newEmployee = new Employee

{

    FirstName = "Kira",

    LastName = "Smith"

};

var newTerritory = new Territory

{

    TerritoryID = "12345",

    TerritoryDescription = "Anytown",

    Region = db.Regions.First()

};

var newEmployeeTerritory = new EmployeeTerritory

{

    Employee = newEmployee,

    Territory = newTerritory

};

db.Employees.InsertOnSubmit(newEmployee);

db.Territories.InsertOnSubmit(newTerritory);

db.EmployeeTerritories.InsertOnSubmit(newEmployeeTerritory);

db.SubmitChanges();

Region nwRegion = new Region()

{

    RegionID = 32,

    RegionDescription = "Rainy"

};

db.Regions.InsertOnSubmit(nwRegion);

db.SubmitChanges();

Customer cust =

    db.Customers.First(c => c.CustomerID == "ALFKI");

cust.ContactTitle = "Vice President";

db.SubmitChanges();

var q = from p in db.Products

        where p.CategoryID == 1

        select p;

foreach (var p in q)

{

    p.UnitPrice += 1.00M;

}

db.SubmitChanges();

OrderDetail orderDetail =

    db.OrderDetails.First

    (c => c.OrderID == 10255 && c.ProductID == 36);

db.OrderDetails.DeleteOnSubmit(orderDetail);

db.SubmitChanges();

var orderDetails =

    from o in db.OrderDetails

    where o.Order.CustomerID == "WARTH" &&

    o.Order.EmployeeID == 3

    select o;

var order =

    (from o in db.Orders

     where o.CustomerID == "WARTH" && o.EmployeeID == 3

     select o).First();

foreach (OrderDetail od in orderDetails)

{

    db.OrderDetails.DeleteOnSubmit(od);

}

db.Orders.DeleteOnSubmit(order);

db.SubmitChanges();

Order order = db.Orders.First(x => x.OrderID == 10248);

OrderDetail od = 

    order.OrderDetails.First(d => d.ProductID == 11);

order.OrderDetails.Remove(od);

db.SubmitChanges();

//通常，通过从其他层反序列化 XML 来获取要附加的实体

//不支持将实体从一个DataContext附加到另一个DataContext

//因此若要复制反序列化实体的操作，将在此处重新创建这些实体

Customer c1;

List<Order> deserializedOrders = new List<Order>();

Customer deserializedC1;

using (NorthwindDataContext tempdb = new NorthwindDataContext())

{

    c1 = tempdb.Customers.Single(c => c.CustomerID == "ALFKI");

    deserializedC1 = new Customer

    {

        Address = c1.Address,

        City = c1.City,

        CompanyName = c1.CompanyName,

        ContactName = c1.ContactName,

        ContactTitle = c1.ContactTitle,

        Country = c1.Country,

        CustomerID = c1.CustomerID,

        Fax = c1.Fax,

        Phone = c1.Phone,

        PostalCode = c1.PostalCode,

        Region = c1.Region

    };

    Customer tempcust =

        tempdb.Customers.Single(c => c.CustomerID == "ANTON");

    foreach (Order o in tempcust.Orders)

    {

        deserializedOrders.Add(new Order

        {

            CustomerID = o.CustomerID,

            EmployeeID = o.EmployeeID,

            Freight = o.Freight,

            OrderDate = o.OrderDate,

            OrderID = o.OrderID,

            RequiredDate = o.RequiredDate,

            ShipAddress = o.ShipAddress,

            ShipCity = o.ShipCity,

            ShipName = o.ShipName,

            ShipCountry = o.ShipCountry,

            ShippedDate = o.ShippedDate,

            ShipPostalCode = o.ShipPostalCode,

            ShipRegion = o.ShipRegion,

            ShipVia = o.ShipVia

        });

    }

}

using (NorthwindDataContext db2 = new NorthwindDataContext())

{

    //将第一个实体附加到当前数据上下文，以跟踪更改

    //对Customer更新，不能写错

    db2.Customers.Attach(deserializedC1);

    //更改所跟踪的实体

    deserializedC1.Address = "123 First Ave";

    //附加订单列表中的所有实体

    db2.Orders.AttachAll(deserializedOrders);

    //将订单更新为属于其他客户

    foreach (Order o in deserializedOrders)

    {

        o.CustomerID = "CHOPS";

    }

    //在当前数据上下文中提交更改

    db2.SubmitChanges();

}

//通常，通过从其他层反序列化XML获取要附加的实体

//此示例使用 LoadWith 在一个查询中预先加载客户和订单，

//并禁用延迟加载

Customer cust = null;

using (NorthwindDataContext tempdb = new NorthwindDataContext())

{

    DataLoadOptions shape = new DataLoadOptions();

    shape.LoadWith<Customer>(c => c.Orders);

    //加载第一个客户实体及其订单

    tempdb.LoadOptions = shape;

    tempdb.DeferredLoadingEnabled = false;

    cust = tempdb.Customers.First(x => x.CustomerID == "ALFKI");

}

Order orderA = cust.Orders.First();

Order orderB = cust.Orders.First(x => x.OrderID > orderA.OrderID);

using (NorthwindDataContext db2 = new NorthwindDataContext())

{

    //将第一个实体附加到当前数据上下文，以跟踪更改

    db2.Customers.Attach(cust);

    //附加相关订单以进行跟踪; 否则将在提交时插入它们

    db2.Orders.AttachAll(cust.Orders.ToList());

    //更新客户的Phone.

    cust.Phone = "2345 5436";

    //更新第一个订单OrderA的ShipCity.

    orderA.ShipCity = "Redmond";

    //移除第二个订单OrderB.

    cust.Orders.Remove(orderB);

    //添加一个新的订单Order到客户Customer中.

    Order orderC = new Order() { ShipCity = "New York" };

    cust.Orders.Add(orderC);

    //提交执行

    db2.SubmitChanges();

}

//我们打开一个新的连接来模拟另外一个用户

NorthwindDataContext otherUser_db = new NorthwindDataContext();

var otherUser_product =

    otherUser_db.Products.First(p => p.ProductID == 1);

otherUser_product.UnitPrice = 999.99M;

otherUser_db.SubmitChanges();

//我们当前连接

var product = db.Products.First(p => p.ProductID == 1);

product.UnitPrice = 777.77M;

try

{

    db.SubmitChanges();//当前连接执行成功

}

catch (ChangeConflictException)

{

}

//当前用户

var product = db.Products.First(p => p.ProductID == 1);

//我们打开一个新的连接来模拟另外一个用户

NorthwindDataContext otherUser_db = new NorthwindDataContext() ;

var otherUser_product = 

    otherUser_db.Products.First(p => p.ProductID == 1);

otherUser_product.UnitPrice = 999.99M;

otherUser_db.SubmitChanges();

//当前用户修改

product.UnitPrice = 777.77M;

try

{

    db.SubmitChanges();

}

catch (ChangeConflictException)

{

    //发生异常！

}

try

{

    Product prod1 = db.Products.First(p => p.ProductID == 4);

    Product prod2 = db.Products.First(p => p.ProductID == 5);

    prod1.UnitsInStock -= 3;

    prod2.UnitsInStock -= 5;//错误:库存数量的单位不能是负数

    //要么全部成功要么全部失败

    db.SubmitChanges();

}

catch (System.Data.SqlClient.SqlException e)

{

    //执行异常处理

}

using (TransactionScope ts = new TransactionScope())

{

    try

    {

        Product prod1 = db.Products.First(p => p.ProductID == 4);

        Product prod2 = db.Products.First(p => p.ProductID == 5);

        prod1.UnitsInStock -= 3;

        prod2.UnitsInStock -= 5;//错误:库存数量的单位不能是负数

        db.SubmitChanges();

    }

    catch (System.Data.SqlClient.SqlException e)

    {

        //执行异常处理

    }

}

var q =

    from e in db.Employees

    where e.ReportsToEmployee == null

    select e;

var q =

    from e in db.Employees

    where !e.ReportsTo.HasValue

    select e;

var q =

    from e in db.Employees

    where e.ReportsTo.HasValue

    select new

    {

        e.FirstName,

        e.LastName,

        ReportsTo = e.ReportsTo.Value

    };

var q =

    from c in db.Customers

    select new

    {

        c.CustomerID,

        Location = c.City + ", " + c.Country

    };

var q =

    from p in db.Products

    where p.ProductName.Length < 10

    select p;

var q =

    from c in db.Customers

    where c.ContactName.Contains("Anders")

    select c;

var q =

    from c in db.Customers

    select new

    {

        c.ContactName,

        SpacePos = c.ContactName.IndexOf(" ")

    };

var q =

    from c in db.Customers

    where c.ContactName.StartsWith("Maria")

    select c;

var q =

    from c in db.Customers

    where c.ContactName.EndsWith("Anders")

    select c;

var q =

    from p in db.Products

    select p.ProductName.Substring(3);

var q =

    from e in db.Employees

    where e.HomePhone.Substring(6, 3) == "555"

    select e;

var q =

    from e in db.Employees

    select new

    {

        LastName = e.LastName.ToUpper(),

        e.FirstName

    };

var q =

    from c in db.Categories

    select c.CategoryName.ToLower();

var q =

    from e in db.Employees

    select e.HomePhone.Substring(0, 5).Trim();

var q =

    from e in db.Employees

    where e.HomePhone.Substring(4, 1) == ")"

    select e.HomePhone.Insert(5, ":");

var q =

    from e in db.Employees

    where e.HomePhone.Substring(4, 1) == ")"

    select e.HomePhone.Remove(9);

var q =

    from e in db.Employees

    where e.HomePhone.Substring(4, 1) == ")"

    select e.HomePhone.Remove(0, 6);

var q =

    from s in db.Suppliers

    select new

    {

        s.CompanyName,

        Country = s.Country

        .Replace("UK", "United Kingdom")

        .Replace("USA", "United States of America")

    };

var q =

    from o in db.Orders

    where o.OrderDate.Value.Year == 1997

    select o;

var q =

    from o in db.Orders

    where o.OrderDate.Value.Month == 12

    select o;

var q =

    from o in db.Orders

    where o.OrderDate.Value.Day == 31

    select o;

Customer cust1 = db.Customers.First(c => c.CustomerID == "BONAP");

Customer cust2 = db.Customers.First(c => c.CustomerID == "BONAP");

Customer cust1 = db.Customers.First(c => c.CustomerID == "BONAP");

Customer cust2 = (

    from o in db.Orders

    where o.Customer.CustomerID == "BONAP"

    select o )

    .First()

    .Customer;

var custs =

     from c in db.Customers

     where c.City == "Sao Paulo"

     select c;

//上面的查询句法不会导致语句立即执行,仅仅是一个描述性的语句,

只有需要的时候才会执行它

foreach (var cust in custs)

{

    foreach (var ord in cust.Orders)

    {

        //同时查看客户数据和订单数据

    }

}

NorthwindDataContext db = new NorthwindDataContext();

DataLoadOptions ds = new DataLoadOptions();

ds.LoadWith<Customer>(p => p.Orders);//链接2个表，建立关联

db.LoadOptions = ds;

var custs = (

     from c in db2.Customers

     where c.City == "Sao Paulo"

     select c);

foreach (var cust in custs)

{

    foreach (var ord in cust.Orders)

    {

        Console.WriteLine("CustomerID {0} has an OrderID {1}.",

            cust.CustomerID,

            ord.OrderID);

    }

}

NorthwindDataContext db2 = new NorthwindDataContext();

DataLoadOptions ds = new DataLoadOptions();

ds.AssociateWith<Customer>(

     p => p.Orders.Where(o => o.ShipVia > 1));

db2.LoadOptions = ds;

var custs =

     from c in db2.Customers

     where c.City == "London"

     select c;

foreach (var cust in custs)

{

    foreach (var ord in cust.Orders)

    {

        foreach (var orderDetail in ord.OrderDetails)

        {

           //可以查询出cust.CustomerID, ord.OrderID, ord.ShipVia,

           //orderDetail.ProductID, orderDetail.Product.ProductName

        }

    }

}

NorthwindDataContext db2 = new NorthwindDataContext();

DataLoadOptions ds = new DataLoadOptions();

ds.LoadWith<Customer>(p => p.Orders);

ds.LoadWith<Order>(p => p.OrderDetails);

ds.AssociateWith<Order>(

     p => p.OrderDetails.OrderBy(o => o.Quantity));

db2.LoadOptions = ds;

var custs = (

     from c in db2.Customers

     where c.City == "London"

     select c);

foreach (var cust in custs)

{

    foreach (var ord in cust.Orders)

    {

        foreach (var orderDetail in ord.OrderDetails)

        {

           //查询cust.CustomerID, ord.OrderID

           //orderDetail.ProductID, orderDetail.Quantity

        }

    }

}

private IEnumerable<Product> LoadProducts(Category category)

{

    //在执行LINQ to SQL的时候，这个LoadProducts分部方法

    //优先加载执行，这里用存储过程也可以. 

    return this.Products

        .Where(p => p.CategoryID == category.CategoryID)

        .Where(p => !p.Discontinued);

}

NorthwindDataContext db2 = new NorthwindDataContext();

DataLoadOptions ds = new DataLoadOptions();

ds.LoadWith<Category>(p => p.Products);

db2.LoadOptions = ds;

var q = (

     from c in db2.Categories

     where c.CategoryID < 3

     select c);

foreach (var cat in q)

{

    foreach (var prod in cat.Products)

    {

       //查询cat.CategoryID, prod.ProductID

    }

}

var q =

    from p in db.Products.AsEnumerable()

    where isValidProduct(p)

    select p;

var q =

    from c in db.Customers

    where c.City == "London"

    select c;

Customer[] qArray = q.ToArray();

var q =

    from e in db.Employees

    where e.HireDate >= new DateTime(1994, 1, 1)

    select e;

List<Employee> qList = q.ToList();

var q =

    from p in db.Products

    where p.UnitsInStock <= p.ReorderLevel && !p.Discontinued

    select p;

Dictionary<int, Product> qDictionary =

    q.ToDictionary(p => p.ProductID);

foreach (int key in qDictionary.Keys)

{

    Console.WriteLine(key);

}

//新建一个标准的ADO.NET连接:

SqlConnection nwindConn = new SqlConnection(connString);

nwindConn.Open();

// ... 其它的ADO.NET数据操作代码... //

//利用现有的ADO.NET连接来创建一个DataContext:

Northwind interop_db = new Northwind(nwindConn);

var orders =

     from o in interop_db.Orders

     where o.Freight > 500.00M

     select o;

//返回Freight>500.00M的订单

nwindConn.Close();

using (TransactionScope ts = new TransactionScope())

{

    db.SubmitChanges();

    ts.Complete();

}

var q =

     from p in db.Products

     where p.ProductID == 3

     select p;

//使用LINQ to SQL查询出来

//新建一个标准的ADO.NET连接:

SqlConnection nwindConn = new SqlConnection(connString);

nwindConn.Open();

//利用现有的ADO.NET连接来创建一个DataContext:

Northwind interop_db = new Northwind(nwindConn);

SqlTransaction nwindTxn = nwindConn.BeginTransaction();

try

{

    SqlCommand cmd = new SqlCommand("UPDATE Products SET"

    +"QuantityPerUnit = ‘single item‘ WHERE ProductID = 3");

    cmd.Connection = nwindConn;

    cmd.Transaction = nwindTxn;

    cmd.ExecuteNonQuery();

    interop_db.Transaction = nwindTxn;

    Product prod1 = interop_db.Products.First(p => p.ProductID == 4);

    Product prod2 = interop_db.Products.First(p => p.ProductID == 5);

    prod1.UnitsInStock -= 3;

    prod2.UnitsInStock -= 5;//这有一个错误，不能为负数

    interop_db.SubmitChanges();

    nwindTxn.Commit();

}

catch (Exception e)

{

    //如果有一个错误，所有的操作回滚

    Console.WriteLine(e.Message);

}

nwindConn.Close();

var products = db.ExecuteQuery<Product>(

    "SELECT [Product List].ProductID,"+

    "[Product List].ProductName " +

    "FROM Products AS [Product List] " +

    "WHERE [Product List].Discontinued = 0 " +

    "ORDER BY [Product List].ProductName;"

);

db.ExecuteCommand

    ("UPDATE Products SET UnitPrice = UnitPrice + 1.00");

ALTER PROCEDURE [dbo].[NonRowset]

    (@param1 NVARCHAR(15))

AS

BEGIN

    SET NOCOUNT ON;

     DECLARE @count int

     SELECT @count = COUNT(*)FROM Customers 

     WHERECustomers.Region = @Param1

     RETURN @count

END

[Function(Name = "dbo.[Customers Count By Region]")]

public int Customers_Count_By_Region([Parameter

(DbType = "NVarChar(15)")] string param1)

{

    IExecuteResult result = this.ExecuteMethodCall(this,

    ((MethodInfo)(MethodInfo.GetCurrentMethod())), param1);

    return ((int)(result.ReturnValue));

}

int count = db.CustomersCountByRegion("WA");

Console.WriteLine(count);

ALTER PROCEDURE [dbo].[Customers By City]

     -- Add the parameters for the stored procedure here

     (@param1 NVARCHAR(20))

AS

BEGIN

     -- SET NOCOUNT ON added to prevent extra result sets from

     -- interfering with SELECT statements.

     SET NOCOUNT ON;

     SELECT CustomerID, ContactName, CompanyName, City from 

     Customers as c where c.City=@param1

END

[Function(Name="dbo.[Customers By City]")]

public ISingleResult<Customers_By_CityResult> Customers_By_City(

[Parameter(DbType="NVarChar(20)")] string param1)

{

    IExecuteResult result = this.ExecuteMethodCall(this, (

    (MethodInfo)(MethodInfo.GetCurrentMethod())), param1);

    return ((ISingleResult<Customers_By_CityResult>)

    (result.ReturnValue));

}

ISingleResult<Customers_By_CityResult> result =

 db.Customers_By_City("London");

foreach (Customers_By_CityResult cust in result)

{

    Console.WriteLine("CustID={0}; City={1}", cust.CustomerID,

        cust.City);

}

ALTER PROCEDURE [dbo].[SingleRowset_MultiShape]

     -- Add the parameters for the stored procedure here

     (@param1 int )

AS

BEGIN

     -- SET NOCOUNT ON added to prevent extra result sets from

     -- interfering with SELECT statements.

     SET NOCOUNT ON;

     if(@param1 = 1)

     SELECT * from Customers as c where c.Region = ‘WA‘

     else if (@param1 = 2)

     SELECT CustomerID, ContactName, CompanyName from 

     Customers as c where c.Region = ‘WA‘

END

[Function(Name="dbo.[Whole Or Partial Customers Set]")]

public ISingleResult<Whole_Or_Partial_Customers_SetResult> 

Whole_Or_Partial_Customers_Set([Parameter(DbType="Int")] 

System.Nullable<int> param1)

{

    IExecuteResult result = this.ExecuteMethodCall(this, 

    ((MethodInfo)(MethodInfo.GetCurrentMethod())), param1);

    return ((ISingleResult<Whole_Or_Partial_Customers_SetResult>)

    (result.ReturnValue));

}

[Function(Name="dbo.[Whole Or Partial Customers Set]")]

[ResultType(typeof(WholeCustomersSetResult))]

[ResultType(typeof(PartialCustomersSetResult))]

public IMultipleResults Whole_Or_Partial_Customers_Set([Parameter

(DbType="Int")] System.Nullable<int> param1)

{

    IExecuteResult result = this.ExecuteMethodCall(this, 

    ((MethodInfo)(MethodInfo.GetCurrentMethod())), param1);

    return ((IMultipleResults)(result.ReturnValue));

}

public partial class WholeCustomersSetResult

{

    private string _CustomerID;

    private string _CompanyName;

    private string _ContactName;

    private string _ContactTitle;

    private string _Address;

    private string _City;

    private string _Region;

    private string _PostalCode;

    private string _Country;

    private string _Phone;

    private string _Fax;

    public WholeCustomersSetResult()

    {

    }

    [Column(Storage = "_CustomerID", DbType = "NChar(5)")]

    public string CustomerID

    {

        get { return this._CustomerID; }

        set

        {

            if ((this._CustomerID != value))

                this._CustomerID = value;

        }

    }

    [Column(Storage = "_CompanyName", DbType = "NVarChar(40)")]

    public string CompanyName

    {

        get { return this._CompanyName; }

        set

        {

            if ((this._CompanyName != value))

                this._CompanyName = value;

        }

    }

    [Column(Storage = "_ContactName", DbType = "NVarChar(30)")]

    public string ContactName

    {

        get { return this._ContactName; }

        set

        {

            if ((this._ContactName != value))

                this._ContactName = value;

        }

    }

    [Column(Storage = "_ContactTitle", DbType = "NVarChar(30)")]

    public string ContactTitle

    {

        get { return this._ContactTitle; }

        set

        {

            if ((this._ContactTitle != value))

                this._ContactTitle = value;

        }

    }

    [Column(Storage = "_Address", DbType = "NVarChar(60)")]

    public string Address

    {

        get { return this._Address; }

        set

        {

            if ((this._Address != value))

                this._Address = value;

        }

    }

    [Column(Storage = "_City", DbType = "NVarChar(15)")]

    public string City

    {

        get { return this._City; }

        set

        {

            if ((this._City != value))

                this._City = value;

        }

    }

    [Column(Storage = "_Region", DbType = "NVarChar(15)")]

    public string Region

    {

        get { return this._Region; }

        set

        {

            if ((this._Region != value))

                this._Region = value;

        }

    }

    [Column(Storage = "_PostalCode", DbType = "NVarChar(10)")]

    public string PostalCode

    {

        get { return this._PostalCode; }

        set

        {

            if ((this._PostalCode != value))

                this._PostalCode = value;

        }

    }

    [Column(Storage = "_Country", DbType = "NVarChar(15)")]

    public string Country

    {

        get { return this._Country; }

        set

        {

            if ((this._Country != value))

                this._Country = value;

        }

    }

    [Column(Storage = "_Phone", DbType = "NVarChar(24)")]

    public string Phone

    {

        get { return this._Phone; }

        set

        {

            if ((this._Phone != value))

                this._Phone = value;

        }

    }

    [Column(Storage = "_Fax", DbType = "NVarChar(24)")]

    public string Fax

    {

        get { return this._Fax; }

        set

        {

            if ((this._Fax != value))

                this._Fax = value;

        }

    }

}

public partial class PartialCustomersSetResult

{

    private string _CustomerID;

    private string _ContactName;

    private string _CompanyName;

    public PartialCustomersSetResult()

    {

    }

    [Column(Storage = "_CustomerID", DbType = "NChar(5)")]

    public string CustomerID

    {

        get { return this._CustomerID; }

        set

        {

            if ((this._CustomerID != value))

                this._CustomerID = value;

        }

    }

    [Column(Storage = "_ContactName", DbType = "NVarChar(30)")]

    public string ContactName

    {

        get { return this._ContactName; }

        set

        {

            if ((this._ContactName != value))

                this._ContactName = value;

        }

    }

    [Column(Storage = "_CompanyName", DbType = "NVarChar(40)")]

    public string CompanyName

    {

        get { return this._CompanyName; }

        set

        {

            if ((this._CompanyName != value))

                this._CompanyName = value;

        }

    }

}

//返回全部Customer结果集

IMultipleResults result = db.Whole_Or_Partial_Customers_Set(1);

IEnumerable<WholeCustomersSetResult> shape1 =

 result.GetResult<WholeCustomersSetResult>();

foreach (WholeCustomersSetResult compName in shape1)

{

    Console.WriteLine(compName.CompanyName);

}

//返回部分Customer结果集

result = db.Whole_Or_Partial_Customers_Set(2);

IEnumerable<PartialCustomersSetResult> shape2 =

 result.GetResult<PartialCustomersSetResult>();

foreach (PartialCustomersSetResult con in shape2)

{

    Console.WriteLine(con.ContactName);

}

ALTER PROCEDURE [dbo].[Get Customer And Orders]

(@CustomerID nchar(5))

    -- Add the parameters for the stored procedure here

AS

BEGIN

    -- SET NOCOUNT ON added to prevent extra result sets from

    -- interfering with SELECT statements.

    SET NOCOUNT ON;

    SELECT * FROM Customers AS c WHERE c.CustomerID = @CustomerID  

    SELECT * FROM Orders AS o WHERE o.CustomerID = @CustomerID

END

[Function(Name="dbo.[Get Customer And Orders]")]

public ISingleResult<Get_Customer_And_OrdersResult>

Get_Customer_And_Orders([Parameter(Name="CustomerID",

DbType="NChar(5)")] string customerID)

{

     IExecuteResult result = this.ExecuteMethodCall(this,

     ((MethodInfo)(MethodInfo.GetCurrentMethod())), customerID);

     return ((ISingleResult<Get_Customer_And_OrdersResult>)

     (result.ReturnValue));

}

[Function(Name="dbo.[Get Customer And Orders]")]

[ResultType(typeof(CustomerResultSet))]

[ResultType(typeof(OrdersResultSet))]

public IMultipleResults Get_Customer_And_Orders

([Parameter(Name="CustomerID",DbType="NChar(5)")]

string customerID)

{

    IExecuteResult result = this.ExecuteMethodCall(this,

    ((MethodInfo)(MethodInfo.GetCurrentMethod())), customerID);

    return ((IMultipleResults)(result.ReturnValue));

}

public partial class CustomerResultSet

{

    private string _CustomerID;

    private string _CompanyName;

    private string _ContactName;

    private string _ContactTitle;

    private string _Address;

    private string _City;

    private string _Region;

    private string _PostalCode;

    private string _Country;

    private string _Phone;

    private string _Fax;

    public CustomerResultSet()

    {

    }

    [Column(Storage = "_CustomerID", DbType = "NChar(5)")]

    public string CustomerID

    {

        get { return this._CustomerID; }

        set

        {

            if ((this._CustomerID != value))

                this._CustomerID = value;

        }

    }

    [Column(Storage = "_CompanyName", DbType = "NVarChar(40)")]

    public string CompanyName

    {

        get { return this._CompanyName; }

        set

        {

            if ((this._CompanyName != value))

                this._CompanyName = value;

        }

    }

    [Column(Storage = "_ContactName", DbType = "NVarChar(30)")]

    public string ContactName

    {

        get { return this._ContactName; }

        set

        {

            if ((this._ContactName != value))

                this._ContactName = value;

        }

    }

    [Column(Storage = "_ContactTitle", DbType = "NVarChar(30)")]

    public string ContactTitle

    {

        get { return this._ContactTitle; }

        set

        {

            if ((this._ContactTitle != value))

                this._ContactTitle = value;

        }

    }

    [Column(Storage = "_Address", DbType = "NVarChar(60)")]

    public string Address

    {

        get { return this._Address; }

        set

        {

            if ((this._Address != value))

                this._Address = value;

        }

    }

    [Column(Storage = "_City", DbType = "NVarChar(15)")]

    public string City

    {

        get { return this._City; }

        set

        {

            if ((this._City != value))

                this._City = value;

        }

    }

    [Column(Storage = "_Region", DbType = "NVarChar(15)")]

    public string Region

    {

        get { return this._Region; }

        set

        {

            if ((this._Region != value))

                this._Region = value;

        }

    }

    [Column(Storage = "_PostalCode", DbType = "NVarChar(10)")]

    public string PostalCode

    {

        get { return this._PostalCode; }

        set

        {

            if ((this._PostalCode != value))

                this._PostalCode = value;

        }

    }

    [Column(Storage = "_Country", DbType = "NVarChar(15)")]

    public string Country

    {

        get { return this._Country; }

        set

        {

            if ((this._Country != value))

                this._Country = value;

        }

    }

    [Column(Storage = "_Phone", DbType = "NVarChar(24)")]

    public string Phone

    {

        get { return this._Phone; }

        set

        {

            if ((this._Phone != value))

                this._Phone = value;

        }

    }

    [Column(Storage = "_Fax", DbType = "NVarChar(24)")]

    public string Fax

    {

        get { return this._Fax; }

        set

        {

            if ((this._Fax != value))

                this._Fax = value;

        }

    }

}

public partial class OrdersResultSet

{

    private System.Nullable<int> _OrderID;

    private string _CustomerID;

    private System.Nullable<int> _EmployeeID;

    private System.Nullable<System.DateTime> _OrderDate;

    private System.Nullable<System.DateTime> _RequiredDate;

    private System.Nullable<System.DateTime> _ShippedDate;

    private System.Nullable<int> _ShipVia;

    private System.Nullable<decimal> _Freight;

    private string _ShipName;

    private string _ShipAddress;

    private string _ShipCity;

    private string _ShipRegion;

    private string _ShipPostalCode;

    private string _ShipCountry;

    public OrdersResultSet()

    {

    }

    [Column(Storage = "_OrderID", DbType = "Int")]

    public System.Nullable<int> OrderID

    {

        get { return this._OrderID; }

        set

        {

            if ((this._OrderID != value))

                this._OrderID = value;

        }

    }

    [Column(Storage = "_CustomerID", DbType = "NChar(5)")]

    public string CustomerID

    {

        get { return this._CustomerID; }

        set

        {

            if ((this._CustomerID != value))

                this._CustomerID = value;

        }

    }

    [Column(Storage = "_EmployeeID", DbType = "Int")]

    public System.Nullable<int> EmployeeID

    {

        get { return this._EmployeeID; }

        set

        {

            if ((this._EmployeeID != value))

                this._EmployeeID = value;

        }

    }

    [Column(Storage = "_OrderDate", DbType = "DateTime")]

    public System.Nullable<System.DateTime> OrderDate

    {

        get { return this._OrderDate; }

        set

        {

            if ((this._OrderDate != value))

                this._OrderDate = value;

        }

    }

    [Column(Storage = "_RequiredDate", DbType = "DateTime")]

    public System.Nullable<System.DateTime> RequiredDate

    {

        get { return this._RequiredDate; }

        set

        {

            if ((this._RequiredDate != value))

                this._RequiredDate = value;

        }

    }

    [Column(Storage = "_ShippedDate", DbType = "DateTime")]

    public System.Nullable<System.DateTime> ShippedDate

    {

        get { return this._ShippedDate; }

        set

        {

            if ((this._ShippedDate != value))

                this._ShippedDate = value;

        }

    }

    [Column(Storage = "_ShipVia", DbType = "Int")]

    public System.Nullable<int> ShipVia

    {

        get { return this._ShipVia; }

        set

        {

            if ((this._ShipVia != value))

                this._ShipVia = value;

        }

    }

    [Column(Storage = "_Freight", DbType = "Money")]

    public System.Nullable<decimal> Freight

    {

        get { return this._Freight; }

        set

        {

            if ((this._Freight != value))

                this._Freight = value;

        }

    }

    [Column(Storage = "_ShipName", DbType = "NVarChar(40)")]

    public string ShipName

    {

        get { return this._ShipName; }

        set

        {

            if ((this._ShipName != value))

                this._ShipName = value;

        }

    }

    [Column(Storage = "_ShipAddress", DbType = "NVarChar(60)")]

    public string ShipAddress

    {

        get { return this._ShipAddress; }

        set

        {

            if ((this._ShipAddress != value))

                this._ShipAddress = value;

        }

    }

    [Column(Storage = "_ShipCity", DbType = "NVarChar(15)")]

    public string ShipCity

    {

        get { return this._ShipCity; }

        set

        {

            if ((this._ShipCity != value))

                this._ShipCity = value;

        }

    }

    [Column(Storage = "_ShipRegion", DbType = "NVarChar(15)")]

    public string ShipRegion

    {

        get { return this._ShipRegion; }

        set

        {

            if ((this._ShipRegion != value))

                this._ShipRegion = value;

        }

    }

    [Column(Storage = "_ShipPostalCode", DbType = "NVarChar(10)")]

    public string ShipPostalCode

    {

        get { return this._ShipPostalCode; }

        set

        {

            if ((this._ShipPostalCode != value))

                this._ShipPostalCode = value;

        }

    }

    [Column(Storage = "_ShipCountry", DbType = "NVarChar(15)")]

    public string ShipCountry

    {

        get { return this._ShipCountry; }

        set

        {

            if ((this._ShipCountry != value))

                this._ShipCountry = value;

        }

    }

}

IMultipleResults result = db.Get_Customer_And_Orders("SEVES");

//返回Customer结果集

IEnumerable<CustomerResultSet> customer = 

result.GetResult<CustomerResultSet>();

//返回Orders结果集

IEnumerable<OrdersResultSet> orders = 

 result.GetResult<OrdersResultSet>();

//在这里，我们读取CustomerResultSet中的数据

foreach (CustomerResultSet cust in customer)

{

    Console.WriteLine(cust.CustomerID);

}

ALTER PROCEDURE [dbo].[CustOrderTotal] 

@CustomerID nchar(5),

@TotalSales money OUTPUT

AS

SELECT @TotalSales = SUM(OD.UNITPRICE*(1-OD.DISCOUNT) * OD.QUANTITY)

FROM ORDERS O, "ORDER DETAILS" OD

where O.CUSTOMERID = @CustomerID AND O.ORDERID = OD.ORDERID

[Function(Name="dbo.CustOrderTotal")]

public int CustOrderTotal(

[Parameter(Name="CustomerID", DbType="NChar(5)")]string customerID,

[Parameter(Name="TotalSales", DbType="Money")]

  ref System.Nullable<decimal> totalSales)

{

    IExecuteResult result = this.ExecuteMethodCall(this,

    ((MethodInfo)(MethodInfo.GetCurrentMethod())),

    customerID, totalSales);

    totalSales = ((System.Nullable<decimal>)

    (result.GetParameterValue(1)));

    return ((int)(result.ReturnValue));

}

decimal? totalSales = 0;

string customerID = "ALFKI";

db.CustOrderTotal(customerID, ref totalSales);

Console.WriteLine("Total Sales for Customer ‘{0}‘ = {1:C}", 

customerID, totalSales);

ALTER FUNCTION [dbo].[TotalProductUnitPriceByCategory]

(@categoryID int)

RETURNS Money

AS

BEGIN

    -- Declare the return variable here

    DECLARE @ResultVar Money

    -- Add the T-SQL statements to compute the return value here

    SELECT @ResultVar = (Select SUM(UnitPrice)

                        from Products

                        where CategoryID = @categoryID)

    -- Return the result of the function

    RETURN @ResultVar

END

[Function(Name="dbo.TotalProductUnitPriceByCategory",

IsComposable=true)]

public System.Nullable<decimal> TotalProductUnitPriceByCategory(

[Parameter(DbType="Int")] System.Nullable<int> categoryID)

{

    return ((System.Nullable<decimal>)(this.ExecuteMethodCall(this,

    ((MethodInfo)(MethodInfo.GetCurrentMethod())), categoryID)

     .ReturnValue));

}

var q = from c in db.Categories

        select new

        {

            c.CategoryID,

            TotalUnitPrice =

                db.TotalProductUnitPriceByCategory(c.CategoryID)

        };

SELECT [t0].[CategoryID], CONVERT(Decimal(29,4),

[dbo].[TotalProductUnitPriceByCategory]([t0].[CategoryID]))

AS [TotalUnitPrice] FROM [dbo].[Categories] AS [t0]

ALTER FUNCTION [dbo].[MinUnitPriceByCategory]

(@categoryID INT

)

RETURNS Money

AS

BEGIN

    -- Declare the return variable here

    DECLARE @ResultVar Money

    -- Add the T-SQL statements to compute the return value here

    SELECT @ResultVar = MIN(p.UnitPrice) FROM Products as p

    WHERE p.CategoryID = @categoryID

    -- Return the result of the function

    RETURN @ResultVar

END

[Function(Name="dbo.MinUnitPriceByCategory", IsComposable=true)]

public System.Nullable<decimal> MinUnitPriceByCategory(

[Parameter(DbType="Int")] System.Nullable<int> categoryID)

{

    return ((System.Nullable<decimal>)(this.ExecuteMethodCall(

    this, ((MethodInfo)(MethodInfo.GetCurrentMethod())),

    categoryID).ReturnValue));

}

var q =

    from p in db.Products

    where p.UnitPrice ==

    db.MinUnitPriceByCategory(p.CategoryID)

    select p;

SELECT [t0].[ProductID], [t0].[ProductName], [t0].[SupplierID],

[t0].[CategoryID],[t0].[QuantityPerUnit], [t0].[UnitPrice],

[t0].[UnitsInStock], [t0].[UnitsOnOrder],[t0].[ReorderLevel],

[t0].[Discontinued]FROM [dbo].[Products] AS [t0]

WHERE [t0].[UnitPrice] =

[dbo].[MinUnitPriceByCategory]([t0].[CategoryID])

ALTER FUNCTION [dbo].[ProductsUnderThisUnitPrice]

(@price Money

)

RETURNS TABLE

AS

RETURN

    SELECT *

    FROM Products as P

    Where p.UnitPrice < @price

[Function(Name="dbo.ProductsUnderThisUnitPrice",

IsComposable=true)]

public IQueryable<ProductsUnderThisUnitPriceResult>

ProductsUnderThisUnitPrice([Parameter(DbType="Money")]

System.Nullable<decimal> price)

{

    return this.CreateMethodCallQuery

    <ProductsUnderThisUnitPriceResult>(this,

    ((MethodInfo)(MethodInfo.GetCurrentMethod())), price);

}

private System.Nullable<bool> _Discontinued;

public System.Nullable<bool> Discontinued

{

}

var q = from p in db.ProductsUnderThisUnitPrice(10.25M)

        where !(p.Discontinued ?? false)

        select p;

SELECT [t0].[ProductID], [t0].[ProductName], [t0].[SupplierID],

[t0].[CategoryID], [t0].[QuantityPerUnit], [t0].[UnitPrice],

[t0].[UnitsInStock], [t0].[UnitsOnOrder], [t0].[ReorderLevel],

[t0].[Discontinued]

FROM [dbo].[ProductsUnderThisUnitPrice](@p0) AS [t0]

WHERE NOT ((COALESCE([t0].[Discontinued],@p1)) = 1)

-- @p0: Input Money (Size = 0; Prec = 19; Scale = 4) [10.25]

-- @p1: Input Int (Size = 0; Prec = 0; Scale = 0) [0]

var q =

    from c in db.Categories

    join p in db.ProductsUnderThisUnitPrice(8.50M) on

    c.CategoryID equals p.CategoryID into prods

    from p in prods

    select new

    {

        c.CategoryID,

        c.CategoryName,

        p.ProductName,

        p.UnitPrice

    };

SELECT [t0].[CategoryID], [t0].[CategoryName],

[t1].[ProductName], [t1].[UnitPrice]

FROM [dbo].[Categories] AS [t0]

CROSS JOIN [dbo].[ProductsUnderThisUnitPrice](@p0) AS [t1]

WHERE ([t0].[CategoryID]) = [t1].[CategoryID]

-- @p0: Input Money (Size = 0; Prec = 19; Scale = 4) [8.50]

public class NewCreateDB : DataContext

{

    public Table<Person> Persons;

    public NewCreateDB(string connection)

        :

        base(connection)

    {

    }

    public NewCreateDB(System.Data.IDbConnection connection)

        :

        base(connection)

    {

    }

}

[Table(Name = "Person")]

public partial class Person : INotifyPropertyChanged

{

    private int _PersonID;

    private string _PersonName;

    private System.Nullable<int> _Age;

    public Person() { }

    [Column(Storage = "_PersonID", DbType = "INT",

        IsPrimaryKey = true)]

    public int PersonID

    {

        get { return this._PersonID; }

        set

        {

            if ((this._PersonID != value))

            {

                this.OnPropertyChanged("PersonID");

                this._PersonID = value;

                this.OnPropertyChanged("PersonID");

            }

        }

    }

    [Column(Storage = "_PersonName", DbType = "NVarChar(30)")]

    public string PersonName

    {

        get { return this._PersonName; }

        set

        {

            if ((this._PersonName != value))

            {

                this.OnPropertyChanged("PersonName");

                this._PersonName = value;

                this.OnPropertyChanged("PersonName");

            }

        }

    }

    [Column(Storage = "_Age", DbType = "INT")]

    public System.Nullable<int> Age

    {

        get { return this._Age; }

        set

        {

            if ((this._Age != value))

            {

                this.OnPropertyChanged("Age");

                this._Age = value;

                this.OnPropertyChanged("Age");

            }

        }

    }

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged(string PropertyName)

    {

        if ((this.PropertyChanged != null))

        {

            this.PropertyChanged(this,

                new PropertyChangedEventArgs(PropertyName));

        }

    }

}

 //1.新建一个临时文件夹来存放新建的数据库

 string userTempFolder = Environment.GetEnvironmentVariable

 ("SystemDrive") + @"\YJingLee";

 Directory.CreateDirectory(userTempFolder);

 //2.新建数据库NewCreateDB

 string userMDF = System.IO.Path.Combine(userTempFolder,

  @"NewCreateDB.mdf");

 string connStr = String.Format(@"Data Source=.\SQLEXPRESS;

AttachDbFilename={0};Integrated Security=True;

Connect Timeout=30;User Instance=True;

Integrated Security = SSPI;", userMDF);

 NewCreateDB newDB = new NewCreateDB(connStr);

 newDB.CreateDatabase();

 //3.插入数据并查询

 var newRow = new Person

 {

     PersonID = 1,

     PersonName = "YJingLee",

     Age = 22

 };

 newDB.Persons.InsertOnSubmit(newRow);

 newDB.SubmitChanges();

 var q = from x in newDB.Persons

         select x;

 //4.删除数据库

 newDB.DeleteDatabase();

 //5.删除临时目录

 Directory.Delete(userTempFolder);

//检测Northwind数据库是否存在

if (db.DatabaseExists())

    Console.WriteLine("Northwind数据库存在");

else

    Console.WriteLine("Northwind数据库不存在");

//检测NewCreateDB数据库是否存在

string userTempFolder = Environment.GetEnvironmentVariable("Temp");

string userMDF = System.IO.Path.Combine(userTempFolder,

@"NewCreateDB.mdf");

NewCreateDB newDB = new NewCreateDB(userMDF);

if (newDB.DatabaseExists())

    Console.WriteLine("NewCreateDB数据库存在");

else

    Console.WriteLine("NewCreateDB数据库不存在");

//查询

Customer cust = db.Customers.First(c => c.CustomerID == "ALFKI");

//更新数据并调用SubmitChanges()方法

cust.CompanyName = "YJingLee‘s Blog";

db.SubmitChanges();

//更新数据没有调用SubmitChanges()方法

cust.CompanyName = "http://lyj.cnblogs.com";

var c1 = Expression.Parameter(typeof(Customer), "c");

PropertyInfo City = typeof(Customer).GetProperty("City");

var pred = Expression.Lambda<Func<Customer, bool>>(

    Expression.Equal(

    Expression.Property(c1, City),

    Expression.Constant("Seattle")

   ), c1

);

IQueryable custs = db.Customers;

Expression expr = Expression.Call(typeof(Queryable), "Where",

    new Type[] { custs.ElementType }, custs.Expression, pred);

IQueryable<Customer> q = db.Customers.AsQueryable().

Provider.CreateQuery<Customer>(expr);

//关闭日志功能

//db.Log = null;

//使用日志功能：日志输出到控制台窗口

db.Log = Console.Out;

var q = from c in db.Customers

        where c.City == "London"

        select c;

//日志输出到文件

StreamWriter sw = new StreamWriter(Server.MapPath("log.txt"), true);

db.Log = sw;

var q = from c in db.Customers

        where c.City == "London"

        select c;

sw.Close();

//依据IQueryable数据源构造一个查询

IQueryable<Customer> custs = db.Customers;

//组建一个表达式树来创建一个参数

ParameterExpression param =

    Expression.Parameter(typeof(Customer), "c");

//组建表达式树:c.ContactName

Expression selector = Expression.Property(param,

    typeof(Customer).GetProperty("ContactName"));

Expression pred = Expression.Lambda(selector, param);

//组建表达式树:Select(c=>c.ContactName)

Expression expr = Expression.Call(typeof(Queryable), "Select",

    new Type[] { typeof(Customer), typeof(string) },

    Expression.Constant(custs), pred);

//使用表达式树来生成动态查询

IQueryable<string> query = db.Customers.AsQueryable()

    .Provider.CreateQuery<string>(expr);

//使用GetCommand方法获取SQL语句

System.Data.Common.DbCommand cmd = db.GetCommand(query);

Console.WriteLine(cmd.CommandText);

SELECT [t0].[ContactName] FROM [dbo].[Customers] AS [t0]

IQueryable<Customer> custs = db.Customers;

//创建一个参数c

ParameterExpression param =

    Expression.Parameter(typeof(Customer), "c");

//c.City=="London"

Expression left = Expression.Property(param,

    typeof(Customer).GetProperty("City"));

Expression right = Expression.Constant("London");

Expression filter = Expression.Equal(left, right);

Expression pred = Expression.Lambda(filter, param);

//Where(c=>c.City=="London")

Expression expr = Expression.Call(typeof(Queryable), "Where",

    new Type[] { typeof(Customer) },

    Expression.Constant(custs), pred);

//生成动态查询

IQueryable<Customer> query = db.Customers.AsQueryable()

    .Provider.CreateQuery<Customer>(expr);

SELECT [t0].[CustomerID], [t0].[CompanyName], [t0].[ContactName],

[t0].[ContactTitle], [t0].[Address], [t0].[City], [t0].[Region],

[t0].[PostalCode], [t0].[Country], [t0].[Phone], [t0].[Fax]

FROM [dbo].[Customers] AS [t0] WHERE [t0].[City] = @p0

-- @p0: Input NVarChar (Size = 6; Prec = 0; Scale = 0) [London]

IQueryable<Customer> custs = db.Customers;

//创建一个参数c

ParameterExpression param =

   Expression.Parameter(typeof(Customer), "c");

//c.City=="London"

Expression left = Expression.Property(param,

    typeof(Customer).GetProperty("City"));

Expression right = Expression.Constant("London");

Expression filter = Expression.Equal(left, right);

Expression pred = Expression.Lambda(filter, param);

//Where(c=>c.City=="London")

MethodCallExpression whereCallExpression = Expression.Call(

    typeof(Queryable), "Where",

    new Type[] { typeof(Customer) },

    Expression.Constant(custs), pred);

//OrderBy(ContactName => ContactName)

MethodCallExpression orderByCallExpression = Expression.Call(

    typeof(Queryable), "OrderBy",

    new Type[] { typeof(Customer), typeof(string) },

    whereCallExpression,

    Expression.Lambda(Expression.Property

    (param, "ContactName"), param));

//生成动态查询

IQueryable<Customer> query = db.Customers.AsQueryable()

    .Provider.CreateQuery<Customer>(orderByCallExpression);

SELECT [t0].[CustomerID], [t0].[CompanyName], [t0].[ContactName],

[t0].[ContactTitle], [t0].[Address], [t0].[City], [t0].[Region],

[t0].[PostalCode], [t0].[Country], [t0].[Phone], [t0].[Fax]

FROM [dbo].[Customers] AS [t0] WHERE [t0].[City] = @p0

ORDER BY [t0].[ContactName]

-- @p0: Input NVarChar (Size = 6; Prec = 0; Scale = 0) [London]

//e.City

IQueryable<Customer> custs = db.Customers;         

ParameterExpression param1 =

Expression.Parameter(typeof(Customer), "e");

Expression left1 = Expression.Property(param1,

    typeof(Customer).GetProperty("City"));

Expression pred1 = Expression.Lambda(left1, param1);

//c.City

IQueryable<Employee> employees = db.Employees;

ParameterExpression param2 =

Expression.Parameter(typeof(Employee), "c");

Expression left2 = Expression.Property(param2,

    typeof(Employee).GetProperty("City"));

Expression pred2 = Expression.Lambda(left2, param2);

//Select(e=>e.City)

Expression expr1 = Expression.Call(typeof(Queryable), "Select",

    new Type[] { typeof(Customer), typeof(string) },

    Expression.Constant(custs), pred1);

//Select(c=>c.City)

Expression expr2 = Expression.Call(typeof(Queryable), "Select",

    new Type[] { typeof(Employee), typeof(string) },

    Expression.Constant(employees), pred2);

//生成动态查询

IQueryable<string> q1 = db.Customers.AsQueryable()

    .Provider.CreateQuery<string>(expr1);

IQueryable<string> q2 = db.Employees.AsQueryable()

    .Provider.CreateQuery<string>(expr2);

//并集

var q3 = q1.Union(q2);

SELECT [t2].[City]

FROM (

    SELECT [t0].[City] FROM [dbo].[Customers] AS [t0]

    UNION

    SELECT [t1].[City] FROM [dbo].[Employees] AS [t1]

    ) AS [t2]

//ContactID是主键ID，插入一条数据，系统自动分配ID

Contact con = new Contact()

{

    CompanyName = "New Era",

    Phone = "(123)-456-7890"

};

db.Contacts.InsertOnSubmit(con);

db.SubmitChanges();

var q =

    from i in db.Invoices

    where i.ShipCity == "London"

    select new

    {

        i.OrderID,

        i.ProductName,

        i.Quantity,

        i.CustomerName

    };

SELECT [t0].[OrderID], [t0].[ProductName], [t0].[Quantity],

[t0].[CustomerName] FROM [dbo].[Invoices] AS [t0]

WHERE [t0].[ShipCity] = @p0

-- @p0: Input NVarChar (Size = 6; Prec = 0; Scale = 0) [London]

var q =

    from qo in db.Quarterly_Orders

    select qo;

SELECT [t0].[CustomerID], [t0].[CompanyName], [t0].[City],

[t0].[Country] FROM [dbo].[Quarterly Orders] AS [t0]

[Table(Name = "dbo.Contacts")]

[InheritanceMapping(Code = "Unknown", Type = typeof(Contact),

                    IsDefault = true)]

[InheritanceMapping(Code = "Employee", Type = typeof(EmployeeContact))]

[InheritanceMapping(Code = "Supplier", Type = typeof(SupplierContact))]

[InheritanceMapping(Code = "Customer", Type = typeof(CustomerContact))]

[InheritanceMapping(Code = "Shipper", Type = typeof(ShipperContact))]

public partial class Contact :

INotifyPropertyChanging, INotifyPropertyChanged

{

    [Column(Storage = "_ContactID",IsPrimaryKey = true,

    IsDbGenerated = true)]

    public int ContactID{ }

    [Column(Storage = "_ContactType",IsDiscriminator = true)]

    public string ContactType{ }

}

public abstract partial class FullContact : Contact{ }

public partial class EmployeeContact : FullContact{ }

public partial class SupplierContact : FullContact{ }

public partial class CustomerContact : FullContact{ }

public partial class ShipperContact : Contact{ }

var cons = from c in db.Contacts                      

           select c;

foreach (var con in cons) {

    Console.WriteLine("Company name: {0}", con.CompanyName);

    Console.WriteLine("Phone: {0}", con.Phone);

    Console.WriteLine("This is a {0}", con.GetType());

}

var cons = from c in db.Contacts.OfType<CustomerContact>()

           select c;

SELECT [t0].[ContactType], [t0].[ContactName], [t0].[ContactTitle],

[t0].[Address],[t0].[City], [t0].[Region], [t0].[PostalCode],

[t0].[Country], [t0].[Fax],[t0].[ContactID], [t0].[CompanyName],

[t0].[Phone] FROM [dbo].[Contacts] AS [t0]

WHERE ([t0].[ContactType] = @p0) AND ([t0].[ContactType] IS NOT NULL)

-- @p0: Input NVarChar (Size = 8; Prec = 0; Scale = 0) [Customer]

var cons = from c in db.Contacts

           where c is ShipperContact

           select c;

SELECT [t0].[ContactType], [t0].[ContactID], [t0].[CompanyName],

[t0].[Phone],[t0].[HomePage], [t0].[ContactName],

[t0].[ContactTitle], [t0].[Address], [t0].[City],

[t0].[Region], [t0].[PostalCode], [t0].[Country],

[t0].[Fax],[t0].[PhotoPath], [t0].[Photo], [t0].[Extension]

FROM [dbo].[Contacts] AS [t0] WHERE ([t0].[ContactType] = @p0)

AND ([t0].[ContactType] IS NOT NULL)

-- @p0: Input NVarChar (Size = 7; Prec = 0; Scale = 0) [Shipper]

var cons = from c in db.Contacts

           select c as FullContact;

SELECT [t0].[ContactType], [t0].[HomePage], [t0].[ContactName],

[t0].[ContactTitle],[t0].[Address], [t0].[City],

[t0].[Region], [t0].[PostalCode], [t0].[Country],

[t0].[Fax], [t0].[ContactID], [t0].[CompanyName],

[t0].[Phone], [t0].[PhotoPath],[t0].[Photo], [t0].[Extension]

 FROM [dbo].[Contacts] AS [t0]

var cons = from c in db.Contacts

           where c.ContactType == "Customer" &&

                     ((CustomerContact)c).City == "London"

           select c;

SELECT [t0].[ContactType], [t0].[ContactID], [t0].[CompanyName],

[t0].[Phone], [t0].[HomePage],[t0].[ContactName],

[t0].[ContactTitle], [t0].[Address], [t0].[City], [t0].[Region],

[t0].[PostalCode], [t0].[Country], [t0].[Fax], [t0].[PhotoPath],

[t0].[Photo], [t0].[Extension]FROM [dbo].[Contacts] AS [t0]

WHERE ([t0].[ContactType] = @p0) AND ([t0].[City] = @p1)

-- @p0: Input NVarChar (Size = 8; Prec = 0; Scale = 0) [Customer]

-- @p1: Input NVarChar (Size = 6; Prec = 0; Scale = 0) [London]

//插入一条数据默认使用正常的映射关系

Contact contact = new Contact()

{

    ContactType = null,

    CompanyName = "Unknown Company",

    Phone = "333-444-5555"

};

db.Contacts.InsertOnSubmit(contact);

db.SubmitChanges();

//查询一条数据默认使用继承映射关系

var con =

    (from c in db.Contacts

     where c.CompanyName == "Unknown Company" &&

                            c.Phone == "333-444-5555"

     select c).First();

INSERT INTO [dbo].[Contacts]([ContactType], [CompanyName],

[Phone]) VALUES (@p0, @p1, @p2)

SELECT TOP (1) [t0].[ContactType], [t0].[ContactID],

[t0].[CompanyName], [t0].[Phone],[t0].[HomePage],

[t0].[ContactName], [t0].[ContactTitle], [t0].[Address],

[t0].[City],[t0].[Region], [t0].[PostalCode], [t0].[Country],

[t0].[Fax], [t0].[PhotoPath],[t0].[Photo], [t0].[Extension]

FROM [dbo].[Contacts] AS [t0]

WHERE ([t0].[CompanyName] = @p0) AND ([t0].[Phone] = @p1)

-- @p0: Input NVarChar (Size = 15; Prec = 0; Scale = 0)

    [Unknown Company]

-- @p1: Input NVarChar (Size = 12; Prec = 0; Scale = 0)

    [333-444-5555]

//1.在插入之前查询一下，没有数据

var ShipperContacts =

    from sc in db.Contacts.OfType<ShipperContact>()

    where sc.CompanyName == "Northwind Shipper"

    select sc;

//2.插入数据

ShipperContact nsc = new ShipperContact()

{

    CompanyName = "Northwind Shipper",

    Phone = "(123)-456-7890"

};

db.Contacts.InsertOnSubmit(nsc);

db.SubmitChanges();

//3.查询数据，有一条记录

ShipperContacts =

    from sc in db.Contacts.OfType<ShipperContact>()

    where sc.CompanyName == "Northwind Shipper"

    select sc;

//4.删除记录

db.Contacts.DeleteOnSubmit(nsc);

db.SubmitChanges();

SELECT COUNT(*) AS [value] FROM [dbo].[Contacts] AS [t0]

WHERE ([t0].[CompanyName] = @p0) AND ([t0].[ContactType] = @p1)

AND ([t0].[ContactType] IS NOT NULL)

-- @p0: Input NVarChar [Northwind Shipper]

-- @p1: Input NVarChar [Shipper]

INSERT INTO [dbo].[Contacts]([ContactType], [CompanyName], [Phone])

VALUES (@p0, @p1, @p2)

-- @p0: Input NVarChar  [Shipper]

-- @p1: Input NVarChar  [Northwind Shipper]

-- @p2: Input NVarChar  [(123)-456-7890]

SELECT COUNT(*) AS [value] FROM [dbo].[Contacts] AS [t0]

WHERE ([t0].[CompanyName] = @p0) AND ([t0].[ContactType] = @p1)

AND ([t0].[ContactType] IS NOT NULL)

-- @p0: Input NVarChar [Northwind Shipper]

-- @p1: Input NVarChar [Shipper]

DELETE FROM [dbo].[Contacts] WHERE ([ContactID] = @p0) AND

([ContactType] = @p1) AND ([CompanyName] = @p2) AND ([Phone] = @p3)

-- @p0: Input Int  [159]

-- @p1: Input NVarChar  [Shipper]

-- @p2: Input NVarChar  [Northwind Shipper]

-- @p3: Input NVarChar  [(123)-456-7890]

-- @p4: Input NVarChar  [Unknown]

-- @p5: Input NVarChar (Size = 8; Prec = 0; Scale = 0) [Supplier]

-- @p6: Input NVarChar (Size = 7; Prec = 0; Scale = 0) [Shipper]

-- @p7: Input NVarChar (Size = 8; Prec = 0; Scale = 0) [Employee]

-- @p8: Input NVarChar (Size = 8; Prec = 0; Scale = 0) [Customer]