EF Core，使用包含或再次上下文

Question

开始于：

"Eager loading a collection navigation in a single query may cause performance issues."

参见：Source

并且建议使用带有 include 的拆分查询。我想知道是否不是包含在下面的查询中：

            var task = await context.Tasks                   
                .Include(x => x.TaskDependencies)                 
                .Select(x => new TaskBaseModel
                {
                    Id = x.Id,
                    Name = x.Name,
                    Description = x.Description,                        
                    TaskDependencies= x.TaskDependencies.ToArray()
                })
                .SingleOrDefaultAsync(x => x.Id == _id);

我应该这样做：

                var task = await context.Tasks                                                       
                    .Select(x => new TaskBaseModel
                    {
                        Id = x.Id,
                        Name = x.Name,
                        Description = x.Description,                        
                        TaskDependencies= context.TaskDependencies
                           .Where(y => y.TaskId == x.Id).ToArray()
                    })
                    .SingleOrDefaultAsync(x => x.Id == _id);  

有人知道这方面的信息吗？关于性能等..

此致

Answer 1

两个查询应该具有相同的性能 SQL。请注意，Include 后跟 Select 会被 EF Core 忽略。

所以，最舒服的查询是：

var task = await context.Tasks                   
    .Select(x => new TaskBaseModel
    {
        Id = x.Id,
        Name = x.Name,
        Description = x.Description,                        
        TaskDependencies = x.TaskDependencies.ToArray()
    })
    .SingleOrDefaultAsync(x => x.Id == _id);