Metot Tabanlı Sorgu Söz Dizimi Örnekleri: Projeksiyon
Bu konudaki örnekler, yöntem tabanlı sorgu söz dizimini Select kullanarak AdventureWorks Satış Modeli'ni sorgulamak için ve SelectMany yöntemlerinin nasıl kullanılacağını göstermektedir. Bu örneklerde kullanılan AdventureWorks Satış Modeli, AdventureWorks örnek veritabanındaki Contact, Address, Product, SalesOrderHeader ve SalesOrderDetail tablolarından oluşturulur.
Bu konudaki örneklerde aşağıdaki using
/Imports
deyimler 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
Seç
Örnek
Aşağıdaki örnek, ve Product.ProductID
özelliklerini anonim tür dizisine Product.Name
yansıtmak için yöntemini kullanırSelect.
using (AdventureWorksEntities context = new AdventureWorksEntities())
{
var query = context.Products
.Select(product => new
{
ProductId = product.ProductID,
ProductName = product.Name
});
Console.WriteLine("Product Info:");
foreach (var productInfo in query)
{
Console.WriteLine("Product Id: {0} Product name: {1} ",
productInfo.ProductId, productInfo.ProductName);
}
}
Using context As New AdventureWorksEntities
Dim query = context.Products _
.Select(Function(prod) New With _
{ _
.ProductName = prod.Name, _
.ProductId = prod.ProductID _
})
Console.WriteLine("Product Info:")
For Each productInfo In query
Console.WriteLine("Product Id: {0} Product name: {1} ", _
productInfo.ProductId, productInfo.ProductName)
Next
End Using
Örnek
Aşağıdaki örnek, yalnızca ürün adlarından oluşan bir dizi döndürmek için yöntemini kullanır Select .
using (AdventureWorksEntities context = new AdventureWorksEntities())
{
IQueryable<string> productNames = context.Products
.Select(p => p.Name);
Console.WriteLine("Product Names:");
foreach (String productName in productNames)
{
Console.WriteLine(productName);
}
}
Using context As New AdventureWorksEntities
Dim productNames = context.Products _
.Select(Function(p) p.Name())
Console.WriteLine("Product Names:")
For Each productName In productNames
Console.WriteLine(productName)
Next
End Using
Selectmany
Örnek
Aşağıdaki örnek, 500,00'den küçük olan TotalDue
tüm siparişleri seçmek için yöntemini kullanırSelectMany.
decimal totalDue = 500.00M;
using (AdventureWorksEntities context = new AdventureWorksEntities())
{
ObjectSet<Contact> contacts = context.Contacts;
ObjectSet<SalesOrderHeader> orders = context.SalesOrderHeaders;
var query =
contacts.SelectMany(
contact => orders.Where(order =>
(contact.ContactID == order.Contact.ContactID)
&& order.TotalDue < totalDue)
.Select(order => new
{
ContactID = contact.ContactID,
LastName = contact.LastName,
FirstName = contact.FirstName,
OrderID = order.SalesOrderID,
Total = order.TotalDue
}));
foreach (var smallOrder in query)
{
Console.WriteLine("Contact ID: {0} Name: {1}, {2} Order ID: {3} Total Due: ${4} ",
smallOrder.ContactID, smallOrder.LastName, smallOrder.FirstName,
smallOrder.OrderID, smallOrder.Total);
}
}
Dim totalDue = 500D
Using context As New AdventureWorksEntities
Dim contacts As ObjectSet(Of Contact) = context.Contacts
Dim orders As ObjectSet(Of SalesOrderHeader) = context.SalesOrderHeaders
Dim query = contacts.SelectMany( _
Function(contact) orders.Where(Function(order) _
(contact.ContactID = order.Contact.ContactID) _
And order.TotalDue < totalDue) _
.Select(Function(order) New With _
{ _
.ContactID = contact.ContactID, _
.LastName = contact.LastName, _
.FirstName = contact.FirstName, _
.OrderID = order.SalesOrderID, _
.Total = order.TotalDue _
}) _
)
For Each smallOrder In query
Console.WriteLine("Contact ID: {0} Name: {1}, {2} Order ID: {3} Total Due: ${4} ", _
smallOrder.ContactID, smallOrder.LastName, smallOrder.FirstName, _
smallOrder.OrderID, smallOrder.Total)
Next
End Using
Örnek
Aşağıdaki örnek, 1 Ekim 2002 veya sonraki bir tarihte siparişin yapıldığı tüm siparişleri seçmek için yöntemini kullanır SelectMany .
using (AdventureWorksEntities context = new AdventureWorksEntities())
{
ObjectSet<Contact> contacts = context.Contacts;
ObjectSet<SalesOrderHeader> orders = context.SalesOrderHeaders;
var query =
contacts.SelectMany(
contact => orders.Where(order =>
(contact.ContactID == order.Contact.ContactID)
&& order.OrderDate >= new DateTime(2002, 10, 1))
.Select(order => new
{
ContactID = contact.ContactID,
LastName = contact.LastName,
FirstName = contact.FirstName,
OrderID = order.SalesOrderID,
OrderDate = order.OrderDate
}));
foreach (var order in query)
{
Console.WriteLine("Contact ID: {0} Name: {1}, {2} Order ID: {3} Order date: {4:d} ",
order.ContactID, order.LastName, order.FirstName,
order.OrderID, order.OrderDate);
}
}
Using context As New AdventureWorksEntities
Dim contacts As ObjectSet(Of Contact) = context.Contacts
Dim orders As ObjectSet(Of SalesOrderHeader) = context.SalesOrderHeaders
Dim query = contacts.SelectMany( _
Function(contact) orders.Where(Function(order) _
(contact.ContactID = order.Contact.ContactID) _
And order.OrderDate >= New DateTime(2002, 10, 1)) _
.Select(Function(order) New With _
{ _
.ContactID = contact.ContactID, _
.LastName = contact.LastName, _
.FirstName = contact.FirstName, _
.OrderID = order.SalesOrderID, _
.OrderDate = order.OrderDate _
}) _
)
For Each order In query
Console.WriteLine("Contact ID: {0} Name: {1}, {2} Order ID: {3} Order date: {4:d} ", _
order.ContactID, order.LastName, order.FirstName, _
order.OrderID, order.OrderDate)
Next
End Using