Method-Based Sorgu Söz Dizimi Örnekleri: Bölümleme

Bu konudaki örneklerde, sorgu ifadesi söz dizimini kullanarak Skip ve Take yöntemlerinin AdventureWorks Satış Modelini sorgulamada nasıl kullanılacağını gösterilmektedir. Bu örneklerde kullanılan AdventureWorks Satış Modeli, AdventureWorks örnek veritabanındaki Contact, Address, Product, SalesOrderHeader ve SalesOrderDetail tablolarından oluşturulur.

Bu konudaki örneklerde aşağıdaki using/Imports deyimleri kullanılır:

using System;
using System.Data;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.Objects;
using System.Globalization;
using System.Data.EntityClient;
using System.Data.SqlClient;
using System.Data.Common;


Option Explicit On
Option Strict On
Imports System.Data.Objects
Imports System.Globalization

Atlamak

Örnek

Aşağıdaki örnek, Kişi tablosundaki ilk üç kişi hariç tüm kişileri almak için Skip yöntemi kullanılarak yapılmıştır.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    // LINQ to Entities only supports Skip on ordered collections.
    IOrderedQueryable<Product> products = context.Products
            .OrderBy(p => p.ListPrice);

    IQueryable<Product> allButFirst3Products = products.Skip(3);

    Console.WriteLine("All but first 3 products:");
    foreach (Product product in allButFirst3Products)
    {
        Console.WriteLine($"Name: {product.Name} \t ID: {product.ProductID}");
    }
}

Using context As New AdventureWorksEntities
    'LINQ to Entities only supports Skip on ordered collections.
    Dim products As IOrderedQueryable(Of Product) = _
            context.Products.OrderBy(Function(p) p.ListPrice)

    Dim allButFirst3Products As IQueryable(Of Product) = products.Skip(3)

    Console.WriteLine("All but first 3 products:")
    For Each product As Product In allButFirst3Products
        Console.WriteLine("Name: {0} \t ID: {1}", _
                product.Name, _
                product.ProductID)
    Next
End Using

Örnek

Aşağıdaki örnek, Seattle'daki ilk iki adres dışında tüm adresleri almak için Skip yöntemini kullanır.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    ObjectSet<Address> addresses = context.Addresses;
    ObjectSet<SalesOrderHeader> orders = context.SalesOrderHeaders;

    //LINQ to Entities only supports Skip on ordered collections.
    var query = (
        from address in addresses
        from order in orders
        where address.AddressID == order.Address.AddressID
             && address.City == "Seattle"
        orderby order.SalesOrderID
        select new
        {
            City = address.City,
            OrderID = order.SalesOrderID,
            OrderDate = order.OrderDate
        }).Skip(2);

    Console.WriteLine("All but first 2 orders in Seattle:");
    foreach (var order in query)
    {
        Console.WriteLine($"City: {order.City} Order ID: {order.OrderID} Total Due: {order.OrderDate:d}");
    }

Using context As New AdventureWorksEntities
    Dim orders As ObjectSet(Of SalesOrderHeader) = context.SalesOrderHeaders
    Dim addresses As ObjectSet(Of Address) = context.Addresses

    'LINQ to Entities only supports Skip on ordered collections.
    Dim query = ( _
        From address In addresses _
        From order In orders _
        Where address.AddressID = order.Address.AddressID _
                 And address.City = "Seattle" _
        Order By order.SalesOrderID _
        Select New With _
        { _
            .City = address.City, _
            .OrderID = order.SalesOrderID, _
            .OrderDate = order.OrderDate _
        }).Skip(2)

    Console.WriteLine("All but first 2 orders in Seattle:")
    For Each order In query
        Console.WriteLine("City: {0} Order ID: {1} Total Due: {2:d}", _
            order.City, order.OrderID, order.OrderDate)
    Next
End Using

Almak

Örnek

Aşağıdaki örnek, Take yöntemini kullanarak İletişim tablosundan yalnızca ilk beş kişiyi alır.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    IQueryable<Contact> first5Contacts = context.Contacts.Take(5);

    Console.WriteLine("First 5 contacts:");
    foreach (Contact contact in first5Contacts)
    {
        Console.WriteLine($"Title = {contact.Title} \t FirstName = {contact.FirstName} \t Lastname = {contact.LastName}");
    }
}

Using context As New AdventureWorksEntities
    Dim contacts As ObjectSet(Of Contact) = context.Contacts

    Dim first5Contacts As IQueryable(Of Contact) = contacts.Take(5)

    Console.WriteLine("First 5 contacts:")
    For Each contact As Contact In first5Contacts
        Console.WriteLine("Title = {0} " & vbTab & " FirstName = {1} " _
            & vbTab & " Lastname = {2}", contact.Title, contact.FirstName, _
            contact.LastName)
    Next
End Using

Örnek

Aşağıdaki örnek, Seattle'daki adreslerin ilk üçünü almak için Take yöntemini kullanır.

String city = "Seattle";
using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    ObjectSet<Address> addresses = context.Addresses;
    ObjectSet<SalesOrderHeader> orders = context.SalesOrderHeaders;

    var query = (
        from address in addresses
        from order in orders
        where address.AddressID == order.Address.AddressID
             && address.City == city
        select new
        {
            City = address.City,
            OrderID = order.SalesOrderID,
            OrderDate = order.OrderDate
        }).Take(3);
    Console.WriteLine("First 3 orders in Seattle:");
    foreach (var order in query)
    {
        Console.WriteLine($"City: {order.City} Order ID: {order.OrderID} Total Due: {order.OrderDate:d}");
    }
}

Dim city = "Seattle"
Using context As New AdventureWorksEntities
    Dim orders As ObjectSet(Of SalesOrderHeader) = context.SalesOrderHeaders
    Dim addresses As ObjectSet(Of Address) = context.Addresses

    Dim query = ( _
        From address In addresses _
        From order In orders _
        Where address.AddressID = order.Address.AddressID _
                 And address.City = city _
        Select New With _
        { _
            .City = address.City, _
            .OrderID = order.SalesOrderID, _
            .OrderDate = order.OrderDate _
        }).Take(3)

    Console.WriteLine("First 3 orders in Seattle:")
    For Each order In query
        Console.WriteLine("City: {0} Order ID: {1} Total Due: {2:d}", _
            order.City, order.OrderID, order.OrderDate)
    Next
End Using

Ayrıca bkz.

  • Last updated on