Question

I don’t know if I am doing the below method correctly when using sql but here it goes.

I want to display all exam details (exams details (Also know as Session), questions in exam, answers, penalty, images, videos etc) But the way I am trying to do it is one big query but it is not working as no rows are being displayed.

Below are what I want to display for one exam (and only one exam):

• Exam Details
• All questions in Exam
• All Answers to each question and marks each answer worth
• Penalty (see if enabled or not)
• Penalty marks for incorrect answers
• Images in question
• Videos in questions
• Audio in questions
• Module Details
• Student

Below show the fields each section above require from database:

• Exam Details

  SessionId, SessionName, SessionDuration, TotalMarks, SessionWeight

• All questions in Exam

  QuestionId, QuestionNo, QuestionContent, NoofAnswers, QuestionMarks, OptionId, OptionType, ReplyId, ReplyType

• All Answers to each question and marks each answer worth

AnswerId, Answer, AnswerMarks

• Penalty (see if enabled or not)

PenaltyEnabled

• Penalty answers

PenaltyAnswerId, PenaltyAnswer, PenaltyMarks

• Images in question

ImageId, ImageFile

• Videos in questions

VideoId VideoFile

• Audio in questions

AudioId, AudioFile

• Module Details

ModuleId, ModuleNo, ModuleName

• Student

StudentId

My question is how should the SQL code be written in order for all these data to be shown? Do I just need one big query or a lot of little queries? My attempt is at bottom of question but below is the database tables which shows details dealing with one exam and all its details.

TABLES:

Student

StudentId (PK)  StudentForename  StudentSurname
1              James            Parker

Student_Session

SessionId (FK)  StudentId (FK)
1              1

Session

SessionId (PK) SessionName  SessionDuration  TotalMarks  SessionWeight  ModuleId (FK)
1             AAA          01:00:00        30         20            1

Module

ModuleId (PK)  ModuleNo  ModuleName
1              CHI2513   ICT

Question

SessionId FK) QuestionId (PK)  QuestionNo QuestionContent NoofAnswers QuestionMarks OptionId (FK) ReplyId (FK)
1             4                1           Question 1      1           5              1            1
1             5                2           Question 2      1           3              2            1
1             6                3           Question 3      2           6              2            2
1             7                4           Question 4      3           7              5            2
1             8                5           Question 5      1           9              5            1

Answer:

AnswerId (PK) Answer  QuestionId (FK)
1              A       4
2              C       5
3              A       6
4              B       6
5              B       7
6              D       7
7              E       7
8              G       8

Individual Answer

IndividualId (PK)  AnswerId (FK) AnswerMarks  
1                    1              3       
2                    2              5       
3                    3              3       
4                    4              3       
5                    5              2       
6                    6              2       
7                    7              3       
8                    8              9       

Penalty

PenaltyId(PK) SessionId (FK)  PenaltyEnalbed
1             1               1

PenaltyMarks

PenaltyAnswerId (PK) PenaltyAnswer PenaltyMarks QuestionId (FK)
1                     B            1            4
2                     C            1            4
3                     A            1            5
4                     B            1            5
5                     D            1            5
6                     C            2            6
7                     D            2            6
8                     A            1            7
9                     C            1            7
10                    F            1            7
11                    G            1            7
12                    A            0            8
13                    B            0            8
14                    C            1            8
15                    D            1            8
16                    E            1            8
17                    F            0            8

Reply

ReplyId (PK)  ReplyType
1               Single
2               Multiple

Option_Table

OptionId (PK)  OptionType
1               A-C        
2               A-D
3               A-E
4               A-F
5               A-G

Image

ImageId (PK)  ImageFile
1              ImageFile/Tulips.png
2              ImageFile/Daisys.png

Video

VideoId (PK) VideoFile
1              VideoFile/Speech.png

Audio

AudioId (PK) AudioFile
1               AudioFile/Song.png

Image_Question

   ImageQuestionId (PK) ImageId (FK) SessionId (FK)  QuestionNo (FK)
   1                    1             1                2

Video_Question

VideoQuestionId (PK) VideoId (FK) SessionId (FK)  QuestionNo (FK)
1                      1            1                   4

Audio_Question

AudioQuestionId (PK) AudioId (FK) SessionId (FK)  QuestionNo (FK)
1                      1            1                  5

Below was my failed attempt:

SELECT s.SessionId, 
       SessionName, 
       SessionDuration, 
       TotalMarks, 
       SessionWeight, 
       q.QuestionId, 
       q.QuestionNo, 
       QuestionContent, 
       QuestionMarks, 
       q.OptionId, 
       OptionType, 
       q.ReplyId, 
       ReplyType, 
       a.AnswerId, 
       Answer, 
       NoofAnswers, 
       AnswerMarks, 
       PenaltyEnabled, 
       PenaltyAnswerId, 
       PenaltyAnswer, 
       PenaltyMarks, 
       i.ImageId, 
       au.AudioId, 
       v.VideoId, 
       ImageFile, 
       AudioFile, 
       VideoFile, 
       s.ModuleId, 
       ModuleNo, 
       ModuleName, 
       ss.StudentId 
FROM   Student st 
       INNER JOIN Student_Session ss 
               ON st.StudentId = ss.StudentId 
       INNER JOIN Session s 
               ON ss.SessionId = s.SessionId 
       INNER JOIN Question q 
               ON s.SessionId = q.SessionId 
       INNER JOIN Answer a 
               ON q.QuestionId = a.AnswerId 
       INNER JOIN Individual_Answer ia 
               ON a.AnswerId = ia.AnswerId 
       LEFT JOIN Module m 
              ON s.ModuleId = m.ModuleId 
       LEFT JOIN Penalty p 
              ON q.SessionId = p.SessionId 
       LEFT JOIN Option_Table o 
              ON q.OptionId = o.OptionId 
       LEFT JOIN Reply r 
              ON q.ReplyId = r.ReplyId 
       LEFT JOIN Penalty_Marks pm 
              ON q.QuestionId = pm.QuestionId 
       LEFT JOIN Image_Question iq 
              ON q.QuestionId = iq.QuestionNo 
       INNER JOIN Image i 
               ON iq.ImageId = i.ImageId 
       LEFT JOIN Audio_Question aq 
              ON q.QuestionId = aq.QuestionNo 
       INNER JOIN Audio au 
               ON aq.AudioId = au.AudioId 
       LEFT JOIN Video_Question vq 
              ON q.QuestionId = vq.QuestionNo 
       INNER JOIN Video v 
               ON vq.VideoId = v.VideoId 
WHERE  s.SessionId = 1
ORDER  BY q.QuestionId 

UPDATE:

Will the code below be able to insert QuestionId into Image_Question Table after questions submitted: (This is something I found on SO but updated to my table design)

ImageQuestionToken
{
  ImageToken (PK auto)
  SessionId
}

Image{
   ImageId 
   ImageFile
}

Image_Question
{
  Image_QuestionId
  ImageId FK references Image(ImageId)
  QuestionId FK references Question(QuestionId)

}

Question
{
  QuestionId (PK Auto)
  QuestionNo
  QuestionContent
  ....
}

TempImage
{
  ImageToken FK references ImageQuestionToken(ImageToken)
  ImageFile
}

And the logic like so:

1. User requests question form. Server sets token and includes in response to user.
2. User uploads picture including token. Image is stored in temporary table.
3. Step 2 repeated n times.
4. If user submits question with token value, an entry is placed in the questions table and an id is assigned. All images in the TempImage table that share the token get inserted to the image table with the now known QuestionId. The ImageQuestionToken entry is then deleted and cascade deletes the temp images in TempImage.
5. Else user doesn’t submit question then files are deleted and ImageQuestionToken entry deleted.

Answer 1

There’s a problem with your foreign keys in these tables: Image_Question, Audio_Question, and Video_Question.

You are using the column QuestionNo which is not indexed by the table Question.
I would suggest replacing the columns as QuestionId instead and used their values.

Image_Question

ImageQuestionId (PK) ImageId (FK) SessionId (FK)  QuestionNo(FK)
   1                    1             1                2

Video_Question

VideoQuestionId (PK) VideoId (FK) SessionId (FK)  QuestionNo(FK)
   1                      1            1               4

Audio_Question

AudioQuestionId (PK) AudioId (FK) SessionId (FK)  QuestionNo(FK)
   1                      1            1               5

and your statement should look like this:

SELECT s.SessionId, 
       SessionName, 
       SessionDuration, 
       TotalMarks, 
       SessionWeight, 
       q.QuestionId, 
       q.QuestionNo, 
       QuestionContent, 
       QuestionMarks, 
       q.OptionId, 
       OptionType, 
       q.ReplyId, 
       ReplyType, 
       a.AnswerId, 
       Answer, 
       NoofAnswers, 
       AnswerMarks, 
       PenaltyEnabled, 
       PenaltyAnswerId, 
       PenaltyAnswer, 
       PenaltyMarks, 
       i.ImageId, 
       au.AudioId, 
       v.VideoId, 
       ImageFile, 
       AudioFile, 
       VideoFile, 
       s.ModuleId, 
       ModuleNo, 
       ModuleName, 
       ss.StudentId 
FROM   Student st 
       INNER JOIN Student_Session ss 
               ON st.StudentId = ss.StudentId 
       INNER JOIN Session s 
               ON ss.SessionId = s.SessionId 
       INNER JOIN Question q 
               ON s.SessionId = q.SessionId 
       INNER JOIN Answer a 
               ON q.QuestionId = a.AnswerId 
       INNER JOIN Individual_Answer ia 
               ON a.AnswerId = ia.AnswerId 
       LEFT JOIN Module m 
              ON s.ModuleId = m.ModuleId 
       LEFT JOIN Penalty p 
              ON q.SessionId = p.SessionId 
       LEFT JOIN Option_Table o 
              ON q.OptionId = o.OptionId 
       LEFT JOIN Reply r 
              ON q.ReplyId = r.ReplyId 
       LEFT JOIN Penalty_Marks pm 
              ON q.QuestionId = pm.QuestionId 
       LEFT JOIN Image_Question iq 
              ON q.QuestionNo= iq.QuestionNo
       LEFT JOIN Image i
               ON iq.ImageId = i.ImageId 
       LEFT JOIN Audio_Question aq 
              ON q.QuestionNo= aq.QuestionNo
       LEFT JOIN Audio au 
               ON aq.AudioId = au.AudioId 
       LEFT JOIN Video_Question vq 
              ON q.QuestionNo= vq.QuestionNo
       LEFT JOIN Video v 
               ON vq.VideoId = v.VideoId 
WHERE  s.SessionId = 1
ORDER  BY q.QuestionId

update:
You can use the column QuestionNo afterall, you could just add index so you don’t have to overhaul your codes. hehehe

i suggest you add this:

ALTER TABLE `your_schema`.`Question` 
ADD INDEX `your_idx` (`QuestionNo` ASC);

and instead of these:

  LEFT JOIN Image_Question iq 
    ON q.QuestionId = iq.QuestionId -- from iq.QuestionNo
  LEFT JOIN Image i
    ON iq.ImageId = i.ImageId 
  LEFT JOIN Audio_Question aq 
    ON q.QuestionId = aq.QuestionId -- from aq.QuestionNo
  LEFT JOIN Audio au 
    ON aq.AudioId = au.AudioId 
  LEFT JOIN Video_Question vq 
    ON q.QuestionId = vq.QuestionId -- from vq.QuestionNo
  LEFT JOIN Video v 
    ON vq.VideoId = v.VideoId

you use these:

  LEFT JOIN Image_Question iq 
    ON q.QuestionNo= iq.QuestionNo
  LEFT JOIN Image i
    ON iq.ImageId = i.ImageId 
  LEFT JOIN Audio_Question aq 
    ON q.QuestionNo= aq.QuestionNo
  LEFT JOIN Audio au 
    ON aq.AudioId = au.AudioId 
  LEFT JOIN Video_Question vq 
    ON q.QuestionNo= vq.QuestionNo
  LEFT JOIN Video v 
    ON vq.VideoId = v.VideoId