방법: 일괄 처리로 쿼리 실행(WCF Data Services)
WCF Data Services 클라이언트 라이브러리를 사용하면 데이터 서비스에 대한 두 개 이상의 쿼리를 단일 일괄 처리로 실행할 수 있습니다. 자세한 내용은 일괄 처리 작업(WCF Data Services)을 참조하십시오.
이 항목의 예제에서는 Northwind 샘플 데이터 서비스 및 자동 생성된 클라이언트 데이터 서비스 클래스를 사용합니다. 이 서비스 및 클라이언트 데이터 클래스는 WCF Data Services 퀵 스타트를 완료하면 만들어집니다.
예제
다음 예제에서는 Northwind 데이터 서비스에서 Customers 개체와 Products 개체를 모두 반환하는 쿼리가 포함된 DataServiceRequest 개체 배열을 실행하는 ExecuteBatch 메서드를 호출하는 방법을 보여 줍니다. 반환된 DataServiceResponse의 QueryOperationResponse 개체 컬렉션이 열거되고 각 QueryOperationResponse에 포함되어 있는 개체 컬렉션도 열거됩니다.
Dim customerId = "ALFKI"
' Create the DataServiceContext using the service URI.
Dim context = New NorthwindEntities(svcUri)
' Create the separate query URI's, one that returns
' a single customer and another that returns all Products.
Dim customerUri = New Uri(svcUri.AbsoluteUri & _
"/Customers('" & customerId & "')/?$expand=Orders")
Dim productsUri = New Uri(svcUri.AbsoluteUri & _
"/Products")
' Create the query requests.
Dim customerQuery = New DataServiceRequest(Of Customer)(customerUri)
Dim productsQuery = New DataServiceRequest(Of Product)(productsUri)
' Add the query requests to a batch request array.
Dim batchRequests = _
New DataServiceRequest() {customerQuery, productsQuery}
Dim batchResponse As DataServiceResponse
Try
' Execute the query batch and get the response.
batchResponse = context.ExecuteBatch(batchRequests)
If batchResponse.IsBatchResponse Then
' Parse the batchResponse.BatchHeaders.
End If
' Enumerate over the results of the query.
For Each response As QueryOperationResponse In batchResponse
' Handle an error response.
If response.StatusCode > 299 OrElse response.StatusCode < 200 Then
Console.WriteLine("An error occurred.")
Console.WriteLine(response.Error.Message)
Else
' Find the response for the Customers query.
If response.Query.ElementType Is GetType(Customer) Then
For Each customer As Customer In response
Console.WriteLine("Customer: {0}", customer.CompanyName)
For Each order As Order In customer.Orders
Console.WriteLine("Order ID: {0} - Freight: {1}", _
order.OrderID, order.Freight)
Next
Next
' Find the response for the Products query.
ElseIf response.Query.ElementType Is GetType(Product) Then
For Each product As Product In response
Console.WriteLine("Product: {0}", product.ProductName)
Next
End If
End If
Next
' This type of error is raised when the data service returns with
' a response code < 200 or >299 in the top level element.
Catch ex As DataServiceRequestException
' Get the response from the exception.
batchResponse = ex.Response
If (batchResponse.IsBatchResponse) Then
' Parse the batchResponse.BatchHeaders.
End If
For Each response As QueryOperationResponse In batchResponse
If response.Error IsNot Nothing Then
Console.WriteLine("An error occurred.")
Console.WriteLine(response.Error.Message)
End If
Next
End Try
string customerId = "ALFKI";
// Create the DataServiceContext using the service URI.
NorthwindEntities context = new NorthwindEntities(svcUri);
// Create the separate query URI's, one that returns
// a single customer and another that returns all Products.
Uri customerUri = new Uri(svcUri.AbsoluteUri +
"/Customers('" + customerId + "')/?$expand=Orders");
Uri productsUri = new Uri(svcUri.AbsoluteUri +
"/Products");
// Create the query requests.
DataServiceRequest<Customer> customerQuery =
new DataServiceRequest<Customer>(customerUri);
DataServiceRequest<Product> productsQuery =
new DataServiceRequest<Product>(productsUri);
// Add the query requests to a batch request array.
DataServiceRequest[] batchRequests =
new DataServiceRequest[]{customerQuery, productsQuery};
DataServiceResponse batchResponse;
try
{
// Execute the query batch and get the response.
batchResponse = context.ExecuteBatch(batchRequests);
if (batchResponse.IsBatchResponse)
{
// Parse the batchResponse.BatchHeaders.
}
// Enumerate over the results of the query.
foreach (QueryOperationResponse response in batchResponse)
{
// Handle an error response.
if (response.StatusCode > 299 || response.StatusCode < 200)
{
Console.WriteLine("An error occurred.");
Console.WriteLine(response.Error.Message);
}
else
{
// Find the response for the Customers query.
if (response.Query.ElementType == typeof(Customer))
{
foreach (Customer customer in response)
{
Console.WriteLine("Customer: {0}", customer.CompanyName);
foreach (Order order in customer.Orders)
{
Console.WriteLine("Order ID: {0} - Freight: {1}",
order.OrderID, order.Freight);
}
}
}
// Find the response for the Products query.
else if (response.Query.ElementType == typeof(Product))
{
foreach (Product product in response)
{
Console.WriteLine("Product: {0}", product.ProductName);
}
}
}
}
}
// This type of error is raised when the data service returns with
// a response code < 200 or >299 in the top level element.
catch (DataServiceRequestException e)
{
// Get the response from the exception.
batchResponse = e.Response;
if (batchResponse.IsBatchResponse)
{
// Parse the batchResponse.BatchHeaders.
}
foreach (QueryOperationResponse response in batchResponse)
{
if (response.Error != null)
{
Console.WriteLine("An error occurred.");
Console.WriteLine(response.Error.Message);
}
}
}