방법: 개체 추가, 수정 및 삭제(Entity Framework)

이 항목에서는 개체 컨텍스트에서 개체를 수정하고 해당 데이터를 데이터베이스에 저장하는 방법을 보여 줍니다.

이 항목의 예제는 Adventure Works Sales 모델을 기반으로 합니다. 이 항목의 코드를 실행하려면 프로젝트에 Adventure Works Sales 모델을 추가하고 프로젝트에서 Entity Framework를 사용하도록 구성해야 합니다. 자세한 내용은 방법: 엔터티 데이터 모델 마법사 사용(Entity Framework) 또는 방법: Entity Framework 프로젝트 수동 구성 및 방법: 엔터티 데이터 모델 수동 정의(Entity Framework)를 참조하십시오.

예제

이 예제에서 개체 쿼리는 지정된 SalesOrderID에 따라 단일 SalesOrderHeader 개체를 반환합니다. 주문의 상태를 5(발송됨)에서 1(처리 중)로 변경하고, 새 항목을 주문에 추가하며, 기존 첫 번째 항목을 삭제합니다. 그런 후 SaveChanges 메서드를 호출하여 변경 내용을 데이터베이스에 씁니다. 그런 다음 주문의 결과 상태를 콘솔에 씁니다.

' Specify the order to update. 
Dim orderId As Integer = 43680

Using context As New AdventureWorksEntities()
    Try
        Dim order = (From o In context.SalesOrderHeaders
            Where o.SalesOrderID = orderId
            Select o).First()

        ' Change the status and ship date of an existing order. 
        order.Status = 1
        order.ShipDate = DateTime.Today

        ' You do not have to call the Load method to load the details for the order, 
        ' because lazy loading is set to true 
        ' by the constructor of the AdventureWorksEntities object. 
        ' With lazy loading set to true the related objects are loaded when 
        ' you access the navigation property. In this case SalesOrderDetails. 

        ' Delete the first item in the order. 
        context.DeleteObject(order.SalesOrderDetails.First())

        ' Create a new SalesOrderDetail object. 
        ' You can use the static CreateObjectName method (the Entity Framework 
        ' adds this method to the generated entity types) instead of the new operator: 
        ' SalesOrderDetail.CreateSalesOrderDetail(1, 0, 2, 750, 1, (decimal)2171.2942, 0, 0, 
        ' Guid.NewGuid(), DateTime.Today)) 
        Dim detail = New SalesOrderDetail With
        {
            .SalesOrderID = 0,
            .SalesOrderDetailID = 0,
            .OrderQty = 2,
            .ProductID = 750,
            .SpecialOfferID = 1,
            .UnitPrice = CDec(2171.2942),
            .UnitPriceDiscount = 0,
            .LineTotal = 0,
            .rowguid = Guid.NewGuid(),
            .ModifiedDate = DateTime.Now
        }
        order.SalesOrderDetails.Add(detail)

        ' Save changes in the object context to the database. 
        Dim changes As Integer = context.SaveChanges()

        Console.WriteLine(changes.ToString() + " changes saved!")
        Console.WriteLine("Updated item for order: {0}", order.SalesOrderID.ToString())

        For Each item As SalesOrderDetail In order.SalesOrderDetails
            Console.WriteLine("Item ID: {0}", item.SalesOrderDetailID.ToString())
            Console.WriteLine("Product: {0}", item.ProductID.ToString())
            Console.WriteLine("Quantity: {0}", item.OrderQty.ToString())
        Next
    Catch ex As UpdateException
        Console.WriteLine(ex.ToString())
    End Try
End Using

// Specify the order to update.
int orderId = 43680;

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    try
    {
        var order = (from o in context.SalesOrderHeaders
                     where o.SalesOrderID == orderId
                     select o).First();

        // Change the status and ship date of an existing order.
        order.Status = 1;
        order.ShipDate = DateTime.Today;

        // You do not have to call the Load method to load the details for the order,
        // because  lazy loading is set to true 
        // by the constructor of the AdventureWorksEntities object. 
        // With  lazy loading set to true the related objects are loaded when
        // you access the navigation property. In this case SalesOrderDetails.

        // Delete the first item in the order.
        context.DeleteObject(order.SalesOrderDetails.First());

        // Create a new SalesOrderDetail object.
        // You can use the static CreateObjectName method (the Entity Framework
        // adds this method to the generated entity types) instead of the new operator:
        // SalesOrderDetail.CreateSalesOrderDetail(1, 0, 2, 750, 1, (decimal)2171.2942, 0, 0,
        //                                         Guid.NewGuid(), DateTime.Today));
        SalesOrderDetail detail = new SalesOrderDetail
        {
            SalesOrderID = 1,
            SalesOrderDetailID = 0,
            OrderQty = 2,
            ProductID = 750,
            SpecialOfferID = 1,
            UnitPrice = (decimal)2171.2942,
            UnitPriceDiscount = 0,
            LineTotal = 0,
            rowguid = Guid.NewGuid(),
            ModifiedDate = DateTime.Now
        };

        order.SalesOrderDetails.Add(detail);

        // Save changes in the object context to the database.
        int changes = context.SaveChanges();

        Console.WriteLine(changes.ToString() + " changes saved!");
        Console.WriteLine("Updated item for order: "
            + order.SalesOrderID.ToString());

        foreach (SalesOrderDetail item in order.SalesOrderDetails)
        {
            Console.WriteLine("Item ID: "
                + item.SalesOrderDetailID.ToString() + "  Product: "
                + item.ProductID.ToString() + "  Quantity: "
                + item.OrderQty.ToString());
        }
    }
    catch (UpdateException ex)
    {
        Console.WriteLine(ex.ToString());
    }
}

참고 항목

개념

개체 만들기, 추가, 수정 및 삭제(Entity Framework)
개체 사용(Entity Framework)