太多的數據庫調用 - NHibernate

我有一個循環瀏覽記錄並在每條記錄上執行選擇的方法。我想要一些指導，以便所有查詢都彙總並在一次往返中發送到數據庫。我知道CreateMultiQuery（）和CreateMultiCriteria（）方法，但我不確定如何在下面的當前代碼中實現？太多的數據庫調用 - NHibernate

感謝

foreach (Roll roll in attendanceRegisterRolls.Items) 
       { 
        RollAttendeeUpdater attendeeUpdater = new RollAttendeeUpdater(enrolmentRepository, roll); 
        attendeeUpdater.**AddNewStudentEnrolmentsAsAttendees();** 
        attendeeUpdater.RefreshEffectiveAttendance(register); 
       } 

**Constructor** 
public RollAttendeeUpdater(IEnrolmentRepository enrolmentRepository, Roll roll) 
    { 
     _roll = roll; 
     _enrolments = enrolmentRepository.GetByRoll(_roll); 
    } 

public interface IEnrolmentRepository : IRepository<Enrolment> 
{ 
    IEnumerable<Enrolment> GetByRoll(Roll roll); 
    bool IsStudyCompleted(string resultCode); 
} 
public IEnumerable<Enrolment> GetByRoll(Roll roll) 
    { 
     var query = _session.CreateQuery(
      @"select e 
      from Enrolment e 
      join fetch e.Student 
      where e.Roll.Id.RollNumber = :rollNumber and e.Roll.Id.Year = :year 
      order by e.EnrolmentStatus"); 

     query.SetString("rollNumber", roll.Id.RollNumber); 
     query.SetString("year", roll.Id.YearAsTwoDigitString); 
     return query.List<Enrolment>(); 
    } 
public void **AddNewStudentEnrolmentsAsAttendees()** 
    { 

     foreach (Enrolment enrolment in _enrolments) 
     { 
      Student student = enrolment.Student; 

      if (student.IsActive) 
       if (_roll.HasAttendee(student.Id) == false) 
        _roll.AddAttendee(student, new DateTimeRange(enrolment.StudyStartDate, enrolment.StudyEndDate)); 
     } 
    } 

public virtual bool HasAttendee(string studentId) 
    { 
     return _attendees.Any(a => a.Student.Id == studentId); 
    }

的AddNewStudentEnrolmentsAsAttendees（）和enrolmentRepository.GetByRoll（_roll）方法返回的SQL語句：

select 
enrolment0_.id_enrolment as id1_1_0_, 
enrolledst1_.id_student as id1_10_1_, 
enrolment0_.study_start_date as study2_1_0_, 
enrolment0_.study_end_date as study3_1_0_, 
enrolment0_.id_eft as id4_1_0_, 
enrolment0_.enrolment_date as enrolment5_1_0_, 
enrolment0_.enrolment_start_date as enrolment6_1_0_, 
enrolment0_.enrolment_status as enrolment7_1_0_, 
enrolment0_.fee_band as fee8_1_0_, 
enrolment0_.id_course as id9_1_0_, 
enrolment0_.limitation_date as limitation10_1_0_, 
enrolment0_.result_date as result11_1_0_, 
enrolment0_.roll_number as roll12_1_0_, 
enrolment0_.year as year1_0_, 
enrolment0_.id_student as id14_1_0_, 
enrolment0_.result_code as result15_1_0_, 
enrolledst1_.surname as surname10_1_, 
enrolledst1_.given_names as given3_10_1_, 
enrolledst1_.preferred_name as preferred4_10_1_, 
enrolledst1_.title as title10_1_, 
enrolledst1_.gender as gender10_1_, 
enrolledst1_.tafe_international_id as tafe7_10_1_, 
enrolledst1_.active_ind as active8_10_1_, 
enrolledst1_.date_of_birth as date9_10_1_ 
from dt_modular_enrolment enrolment0_ inner join dt_student enrolledst1_ on enrolment0_.id_student=enrolledst1_.id_student 
where (
enrolment0_.roll_number=?) 
and 
(
    enrolment0_.year=?) 
order by enrolment0_.enrolment_status; p0 = 'AH0130', 
p1 = '12' 

SELECT 
attendees0_.roll_number as roll5_1_, 
attendees0_.year as year1_, 
attendees0_.id_class_attendee as id1_1_, 
attendees0_.id_class_attendee as id1_12_0_, 
attendees0_.attendance_start_date as attendance2_12_0_, 
attendees0_.attendance_end_date as attendance3_12_0_, 
attendees0_.enrolled_ind as enrolled4_12_0_, 
attendees0_.roll_number as roll5_12_0_, 
attendees0_.year as year12_0_, 
attendees0_.prospective_ind as prospect7_12_0_, 
attendees0_.student_identification as student8_12_0_ 
FROM dt_class_attendee attendees0_ 
WHERE attendees0_.roll_number=? and 
attendees0_.year=?; p0 = 'AH0130', 
p1 = '12'

來源

2012-10-11 Darren

您當前發佈的代碼不包含任何NHibernate查詢。你能更新你的問題，並在下面的方法中顯示你的代碼的樣子：enrolmentRepository.GetByRoll（）？ –

爲什麼你在'RollAttendeeUpdater'中使用'enrolmentRepository'而不是在構造函數中給它註冊。然後，您可以輕鬆批量選擇 – Firo

@Randy - 上面顯示了GetByRoll（）方法，它位於IEnrolmentRepository接口中。我認爲sql是在AddNewStudentEnrolmentsAsAttendees（）上創建的？如果任何人可以張貼他們的想法樣本，我將不勝感激 - 謝謝。 – Darren

也許你應該給RollAttendeeUpdater整個輥組進行更新 - 那麼它就有足夠的知識在同一時間爲所有卷執行GetByRoll（）的一些變體。

或者，讓查詢由調用者完成，並傳入滾動和註冊列表，而不是傳遞存儲庫實例。

來源

2012-10-11 07:25:42

謝謝奧斯卡獎 - 你能給我看一個你的回答的例子嗎？ - 謝謝 – Darren

太多的數據庫調用 - NHibernate

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