Язык программирования C#9 и платформа .NET5 - Троелсен Эндрю

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[Fact]

public void ShouldGetCarsOnOrderWithRelatedPropertiesAsSplitQuery()

{

IQueryable<Car> query = Context.Cars.Where(c => c.Orders.Any())

.Include(c => c.MakeNavigation)

.Include(c => c.Orders).ThenInclude(o => o.CustomerNavigation)

<b>.AsSplitQuery()</b>;

var cars = query.ToList();

Assert.Equal(4, cars.Count);

cars.ForEach(c =>

{

Assert.NotNull(c.MakeNavigation);

Assert.NotNull(c.Orders.ToList()[0].CustomerNavigation);

});

}

Метод

ToQueryString()

возвращает только первый запрос, поэтому последующие запросы были получены с применением профилировщика SQL Server:

SELECT [i].[Id], [i].[Color], [i].[IsDrivable], [i].[MakeId],

[i].[PetName], [i].

[TimeStamp], [m].[Id], [m].[Name], [m].[TimeStamp]

FROM [dbo].[Inventory] AS [i]

INNER JOIN [dbo].[Makes] AS [m] ON [i].[MakeId] = [m].[Id]

WHERE ([i].[IsDrivable] = CAST(1 AS bit)) AND EXISTS (

SELECT 1

FROM [Dbo].[Orders] AS [o]

INNER JOIN (

SELECT [i0].[Id], [i0].[Color], [i0].[IsDrivable], [i0].[MakeId],

[i0].[PetName],

[i0].[TimeStamp]

FROM [dbo].[Inventory] AS [i0]

WHERE [i0].[IsDrivable] = CAST(1 AS bit)

) AS [t] ON [o].[CarId] = [t].[Id]

WHERE ([t].[IsDrivable] = CAST(1 AS bit)) AND ([i].[Id] = [o].[CarId]))

ORDER BY [i].[Id], [m].[Id]

SELECT [t0].[Id], [t0].[CarId], [t0].[CustomerId], [t0].[TimeStamp],

[t0].[Id1], [t0].

[TimeStamp1], [t0].[FirstName], [t0].[FullName],

[t0].[LastName], [i].[Id], [m].[Id]

FROM [dbo].[Inventory] AS [i]

INNER JOIN [dbo].[Makes] AS [m] ON [i].[MakeId] = [m].[Id]

INNER JOIN (

SELECT [o].[Id], [o].[CarId], [o].[CustomerId], [o].[TimeStamp],

[c].[Id] AS [Id1], [c].

[TimeStamp] AS [TimeStamp1], [c].[FirstName],

[c].[FullName], [c].[LastName]

FROM [Dbo].[Orders] AS [o]

INNER JOIN (

SELECT [i0].[Id], [i0].[IsDrivable]

FROM [dbo].[Inventory] AS [i0]

WHERE [i0].[IsDrivable] = CAST(1 AS bit)

) AS [t] ON [o].[CarId] = [t].[Id]

INNER JOIN [Dbo].[Customers] AS [c] ON [o].[CustomerId] = [c].[Id]

WHERE [t].[IsDrivable] = CAST(1 AS bit)

) AS [t0] ON [i].[Id] = [t0].[CarId]

WHERE ([i].[IsDrivable] = CAST(1 AS bit)) AND EXISTS (

SELECT 1

FROM [Dbo].[Orders] AS [o0]

INNER JOIN (

SELECT [i1].[Id], [i1].[Color], [i1].[IsDrivable], [i1].[MakeId],

[i1].[PetName],

[i1].[TimeStamp]

FROM [dbo].[Inventory] AS [i1]

WHERE [i1].[IsDrivable] = CAST(1 AS bit)

) AS [t1] ON [o0].[CarId] = [t1].[Id]

WHERE ([t1].[IsDrivable] = CAST(1 AS bit)) AND ([i].[Id] = [o0].[CarId]))

ORDER BY [i].[Id], [m].[Id]

Будете вы разделять свои запросы или нет, зависит от существующих бизнес-требований.

Фильтрация связанных данных

В версии EF Core 5 появилась возможность фильтрации при включении навигационных свойств типа коллекций. До выхода EF Core 5 единственным способом получения отфильтрованного списка для навигационного свойства типа коллекций было использование явной загрузки. Добавьте в

MakeTests.cs

следующий тест, который демонстрирует получение записей производителей, выпускающих автомобили желтого цвета:

[Fact]

public void ShouldGetAllMakesAndCarsThatAreYellow()

{

var query = Context.Makes.IgnoreQueryFilters()

<b> .Include(x => x.Cars.Where(x => x.Color == "Yellow"));</b>

var qs = query.ToQueryString();

var makes = query.ToList();

Assert.NotNull(makes);

Assert.NotEmpty(makes);

Assert.NotEmpty(makes.Where(x => x.Cars.Any()));