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プロジェクトの1つで構成に問題があり、SQL EFが生成しているのは、（少なくとも私にとっては）予期しないネストを示しているようです。この質問は少し時間がかかりますが、ご容赦ください。

だから、私は次のように設定しているとしましょう：

public class Order
{
    public int Id { get; set; }
    public decimal Amount { get; set; }
    public Address ShippingAddress { get; set; }
}

public class Person
{
    public int Id { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public Address Address { get; set; }
}

public class Address
{
    public int Id { get; set; }
    public string StreetAddress { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public string ZipCode { get; set; }
}

そのように構成されたエンティティを使用して：

public class OrderConfiguration : EntityTypeConfiguration<Order>
{
    public OrderConfiguration()
    {
        ToTable("Orders");

        HasRequired(order => order.ShippingAddress)
            .WithRequiredDependent()
            .Map(mapping => mapping.MapKey("ShippingAddressId"));
    }
}

public class PersonConfiguration : EntityTypeConfiguration<Person>
{
    public PersonConfiguration()
    {
        ToTable("Persons");

        HasRequired(person => person.Address)
            .WithRequiredDependent()
            .Map(mapping => mapping.MapKey("AddressId"));
    }
}

私の目標は、住所が含まれている注文を取得することなので、次のような簡単なクエリを実行します。

var orders = context.Orders
    .Include(order => order.ShippingAddress)
    .Where(order => order.ShippingAddress.State == "FL")
    .ToList();

SQLプロファイラーを監視しているときに、Ordersテーブルから選択してAddressテーブルで内部結合を実行するSQLが生成されることを期待しています。

 SELECT * FROM [dbo].[Orders] AS [Extent1] 
     INNER JOIN [dbo].[Addresses] AS [Extent2] ON [Extent1].[AddressId] = [Extentd2].[Id]
     WHERE [Extent2].[State] == 'FL'

代わりに、私はこれが生成されていることを発見しています：

SELECT 
[Extent1].[Id] AS [Id], 
[Extent1].[Amount] AS [Amount], 
[Join5].[Id1] AS [Id1], 
[Join5].[StreetAddress] AS [StreetAddress], 
[Join5].[City] AS [City], 
[Join5].[State] AS [State], 
[Join5].[ZipCode] AS [ZipCode], 
[Join8].[Id2] AS [Id2], 
[Join11].[Id3] AS [Id3]
FROM     [dbo].[Orders] AS [Extent1]
INNER JOIN  (SELECT [Extent2].[State] AS [State], [Extent3].[Id] AS [Id4]
    FROM   [dbo].[Addresses] AS [Extent2]
    LEFT OUTER JOIN [dbo].[Orders] AS [Extent3] ON [Extent2].[Id] = [Extent3].[ShippingAddressId]
    LEFT OUTER JOIN [dbo].[Persons] AS [Extent4] ON [Extent2].[Id] = [Extent4].[AddressId] ) AS [Join2] ON [Extent1].[Id] = [Join2].[Id4]
LEFT OUTER JOIN  (SELECT [Extent5].[Id] AS [Id1], [Extent5].[StreetAddress] AS [StreetAddress], [Extent5].[City] AS [City], [Extent5].[State] AS [State], [Extent5].[ZipCode] AS [ZipCode], [Extent6].[Id] AS [Id5]
    FROM   [dbo].[Addresses] AS [Extent5]
    LEFT OUTER JOIN [dbo].[Orders] AS [Extent6] ON [Extent5].[Id] = [Extent6].[ShippingAddressId]
    LEFT OUTER JOIN [dbo].[Persons] AS [Extent7] ON [Extent5].[Id] = [Extent7].[AddressId] ) AS [Join5] ON [Extent1].[Id] = [Join5].[Id5]
LEFT OUTER JOIN  (SELECT [Extent9].[Id] AS [Id2]
    FROM   [dbo].[Addresses] AS [Extent8]
    LEFT OUTER JOIN [dbo].[Orders] AS [Extent9] ON [Extent8].[Id] = [Extent9].[ShippingAddressId]
    LEFT OUTER JOIN [dbo].[Persons] AS [Extent10] ON [Extent8].[Id] = [Extent10].[AddressId] ) AS [Join8] ON [Extent1].[Id] = [Join8].[Id2]
LEFT OUTER JOIN  (SELECT [Extent12].[Id] AS [Id6], [Extent13].[Id] AS [Id3]
    FROM   [dbo].[Addresses] AS [Extent11]
    LEFT OUTER JOIN [dbo].[Orders] AS [Extent12] ON [Extent11].[Id] = [Extent12].[ShippingAddressId]
    LEFT OUTER JOIN [dbo].[Persons] AS [Extent13] ON [Extent11].[Id] = [Extent13].[AddressId] ) AS [Join11] ON [Extent1].[Id] = [Join11].[Id6]
WHERE N'FL' = [Join2].[State]

明らかに、これは必要以上の作業です。これを行う簡単な方法はありますか、それともエンティティが正しく構成されていませんか？なぜこれらの余分な結合がすべて引き戻されるのか、またはそれらをその時点で必要なテーブルだけに制限する方法がわかりません。どんな洞察も大歓迎です！

ありがとう、デレク

4

1 に答える 1

1

お気づきのように、.Include()恐ろしい SQL が生成されることがあります。

この状況で最も簡単な解決策は、必要な関連エンティティを初期ロードの直後に明示的にロードすることです。これの欠点は、追加のデータベース呼び出しです。注文ごとに 1 回呼び出されます。

var orders = (
    from order in context.Orders
    where order.ShippingAddress.State == "FL"
    select order)
    .ToList();

var t1 = (
    from order in orders
    from address in order.ShippingAddress
    select address)
    .ToList();
于 2013-03-11T15:30:11.477 に答える