Exemplos de sintaxe da consulta com base em método: Adição a operadoresMethod-Based Query Syntax Examples: Join Operators

Os exemplos neste tópico demonstram como usar os Join métodos e GroupJoin para consultar o modelo de vendas AdventureWorks usando a sintaxe de consulta baseada em método.The examples in this topic demonstrate how to use the Join and GroupJoin methods to query the AdventureWorks Sales Model using method-based query syntax. O Modelo de vendas AdventureWorks usado nesses exemplos é criado a partir das tabelas Contact, Address, Product, SalesOrderHeader e SalesOrderDetail no banco de dados de exemplo AdventureWorks.The AdventureWorks Sales Model used in these examples is built from the Contact, Address, Product, SalesOrderHeader, and SalesOrderDetail tables in the AdventureWorks sample database.

Os exemplos neste tópico usam as seguintes using / Imports instruções:The examples in this topic use the following using/Imports statements:

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

GroupJoinGroupJoin

ExemploExample

O exemplo a seguir executa um GroupJoin nas tabelas SalesOrderHeader e SalesOrderDetail para localizar o número de pedidos por cliente.The following example performs a GroupJoin over the SalesOrderHeader and SalesOrderDetail tables to find the number of orders per customer. Um group join é o equivalente a um left outer join, que retorna cada elemento da primeira fonte de dados (esquerda), mesmo se nenhum elemento correlacionado estiver na outra fonte de dados.A group join is the equivalent of a left outer join, which returns each element of the first (left) data source, even if no correlated elements are in the other data source.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    ObjectSet<SalesOrderHeader> orders = context.SalesOrderHeaders;
    ObjectSet<SalesOrderDetail> details = context.SalesOrderDetails;

    var query = orders.GroupJoin(details,
        order => order.SalesOrderID,
        detail => detail.SalesOrderID,
        (order, orderGroup) => new
        {
            CustomerID = order.SalesOrderID,
            OrderCount = orderGroup.Count()
        });

    foreach (var order in query)
    {
        Console.WriteLine("CustomerID: {0}  Orders Count: {1}",
            order.CustomerID,
            order.OrderCount);
    }
}
Using context As New AdventureWorksEntities
    Dim orders As ObjectSet(Of SalesOrderHeader) = context.SalesOrderHeaders
    Dim details As ObjectSet(Of SalesOrderDetail) = context.SalesOrderDetails

    Dim query = orders.GroupJoin(details, _
            Function(order) order.SalesOrderID, _
            Function(detail) detail.SalesOrderID, _
            Function(order, orderGroup) New With _
            { _
                .CustomerID = order.SalesOrderID, _
                .OrderCount = orderGroup.Count() _
            })

    For Each order In query
        Console.WriteLine("CustomerID: {0}  Orders Count: {1}", _
            order.CustomerID, order.OrderCount)
    Next

End Using

ExemploExample

O exemplo a seguir executa um GroupJoin nas tabelas Contact e SalesOrderHeader para localizar o número de pedidos por contato.The following example performs a GroupJoin over the Contact and SalesOrderHeader tables to find the number of orders per contact. A contagem do pedido e as identificações para cada contato são exibidos.The order count and IDs for each contact are displayed.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    ObjectSet<Contact> contacts = context.Contacts;
    ObjectSet<SalesOrderHeader> orders = context.SalesOrderHeaders;

    var query = contacts.GroupJoin(orders,
        contact => contact.ContactID,
        order => order.Contact.ContactID,
        (contact, contactGroup) => new
        {
            ContactID = contact.ContactID,
            OrderCount = contactGroup.Count(),
            Orders = contactGroup
        });

    foreach (var group in query)
    {
        Console.WriteLine("ContactID: {0}", group.ContactID);
        Console.WriteLine("Order count: {0}", group.OrderCount);
        foreach (var orderInfo in group.Orders)
        {
            Console.WriteLine("   Sale ID: {0}", orderInfo.SalesOrderID);
        }
        Console.WriteLine("");
    }
    }
Using context As New AdventureWorksEntities
    Dim contacts As ObjectSet(Of Contact) = context.Contacts
    Dim orders As ObjectSet(Of SalesOrderHeader) = context.SalesOrderHeaders

    Dim query = contacts.GroupJoin(orders, _
            Function(contact) contact.ContactID, _
            Function(order) order.Contact.ContactID, _
            Function(contact, contactGroup) New With _
            { _
                .ContactID = contact.ContactID, _
                .OrderCount = contactGroup.Count(), _
                .orders = contactGroup.Select(Function(order) order) _
            })

    For Each group In query
        Console.WriteLine("ContactID: {0}", group.ContactID)
        Console.WriteLine("Order count: {0}", group.OrderCount)

        For Each orderInfo In group.orders
            Console.WriteLine("   Sale ID: {0}", orderInfo.SalesOrderID)
        Next

        Console.WriteLine("")
    Next
End Using

JoinJoin

ExemploExample

O exemplo a seguir executa uma união sobre as tabelas de contatos e de SalesOrderHeader.The following example performs a join over the Contact and SalesOrderHeader tables.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    ObjectSet<Contact> contacts = context.Contacts;
    ObjectSet<SalesOrderHeader> orders = context.SalesOrderHeaders;

    var query =
        contacts.Join(
            orders,
            order => order.ContactID,
            contact => contact.Contact.ContactID,
            (contact, order) => new
            {
                ContactID = contact.ContactID,
                SalesOrderID = order.SalesOrderID,
                FirstName = contact.FirstName,
                Lastname = contact.LastName,
                TotalDue = order.TotalDue
            });

    foreach (var contact_order in query)
    {
        Console.WriteLine("ContactID: {0} "
                        + "SalesOrderID: {1} "
                        + "FirstName: {2} "
                        + "Lastname: {3} "
                        + "TotalDue: {4}",
            contact_order.ContactID,
            contact_order.SalesOrderID,
            contact_order.FirstName,
            contact_order.Lastname,
            contact_order.TotalDue);
    }
}
Using context As New AdventureWorksEntities
    Dim contacts As ObjectSet(Of Contact) = context.Contacts
    Dim orders As ObjectSet(Of SalesOrderHeader) = context.SalesOrderHeaders

    Dim query = _
        contacts.Join( _
            orders, _
            Function(ord) ord.ContactID, _
            Function(cont) cont.Contact.ContactID, _
            Function(cont, ord) New With _
                { _
                    .ContactID = cont.ContactID, _
                    .SalesOrderID = ord.SalesOrderID, _
                    .FirstName = cont.FirstName, _
                    .Lastname = cont.LastName, _
                    .TotalDue = ord.TotalDue _
                })

    For Each contact_order In query
        Console.WriteLine("ContactID: {0} " _
            & "SalesOrderID: {1} " & "FirstName: {2} " _
            & "Lastname: {3} " & "TotalDue: {4}", _
            contact_order.ContactID, _
            contact_order.SalesOrderID, _
            contact_order.FirstName, _
            contact_order.Lastname, _
            contact_order.TotalDue)
    Next
End Using

ExemploExample

O exemplo a seguir executa uma união sobre as tabelas de contatos e de SalesOrderHeader, agrupamento os resultados pela identificação de contatosThe following example performs a join over the Contact and SalesOrderHeader tables, grouping the results by contact ID.

using (AdventureWorksEntities context = new AdventureWorksEntities())
{
    ObjectSet<Contact> contacts = context.Contacts;
    ObjectSet<SalesOrderHeader> orders = context.SalesOrderHeaders;

    var query = contacts.Join(
        orders,
        order => order.ContactID,
        contact => contact.Contact.ContactID,
        (contact, order) => new
        {
            ContactID = contact.ContactID,
            SalesOrderID = order.SalesOrderID,
            FirstName = contact.FirstName,
            Lastname = contact.LastName,
            TotalDue = order.TotalDue
        })
            .GroupBy(record => record.ContactID);

    foreach (var group in query)
    {
        foreach (var contact_order in group)
        {
            Console.WriteLine("ContactID: {0} "
                            + "SalesOrderID: {1} "
                            + "FirstName: {2} "
                            + "Lastname: {3} "
                            + "TotalDue: {4}",
                contact_order.ContactID,
                contact_order.SalesOrderID,
                contact_order.FirstName,
                contact_order.Lastname,
                contact_order.TotalDue);
        }
    }
}
Using context As New AdventureWorksEntities
    Dim contacts As ObjectSet(Of Contact) = context.Contacts
    Dim orders As ObjectSet(Of SalesOrderHeader) = context.SalesOrderHeaders

    Dim query = _
        contacts.Join( _
            orders, _
            Function(ord) ord.ContactID, _
            Function(cont) cont.Contact.ContactID, _
            Function(cont, ord) New With _
                { _
                    .ContactID = cont.ContactID, _
                    .SalesOrderID = ord.SalesOrderID, _
                    .FirstName = cont.FirstName, _
                    .Lastname = cont.LastName, _
                    .TotalDue = ord.TotalDue _
                }) _
                .GroupBy(Function(record) record.ContactID)

    For Each group In query
        For Each contact_order In group
            Console.WriteLine("ContactID: {0} " _
                & "SalesOrderID: {1} " & "FirstName: {2} " _
                & "Lastname: {3} " & "TotalDue: {4}", _
                contact_order.ContactID, _
                contact_order.SalesOrderID, _
                contact_order.FirstName, _
                contact_order.Lastname, _
                contact_order.TotalDue)
        Next
    Next
End Using

Veja tambémSee also