FROM [dbo].[Inventory] AS [i]
INNER JOIN [dbo].[Makes] AS [m] ON [i].[MakeId]=[m].[Id]
LEFT JOIN(SELECT [o].[Id], [o].[CarId], [o].[CustomerId], [o].[TimeStamp],
[c].[Id] AS [Id0], [c].[TimeStamp] AS [TimeStamp0],
[c].[FirstName], [c].[FullName], [c].[LastName], [t].[Id] AS [Id1]
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], [t0].[Id], [t0].[Id1], [t0].[Id0];
Чем больше соединений добавляется в запрос LINQ, тем сложнее становится результирующий запрос. В версии EF Core 5 появилась возможность выполнять сложные соединения как разделенные запросы. Детальное обсуждение ищите в предыдущей главе, но вкратце помещение в запрос LINQ вызова метода AsSplitQuery инструктирует инфраструктуру EF Core о необходимости разделения одного обращения к базе данных на несколько обращений. В итоге может повыситься эффективность, но возникает риск несогласованности данных. Добавьте в тестовую оснастку приведенный далее тест:
[Fact]
public void ShouldGetCarsOnOrderWithRelatedPropertiesAsSplitQuery
{
IQueryable
.Include(c => c.MakeNavigation)
.Include(c => c.Orders).ThenInclude(o => o.CustomerNavigation)
.AsSplitQuery;
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],
