Marking scheme for the misdterm 
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Hello all,

Below are some guide lines for marking the midterm.

Questions  1 and 2 (50 points)
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  - For each missing aggegation take off 3 points.
  - For missing VISITS weak entity I take off 5 points.
  - For each missing weak entity (both the entity set and the 
                         identifying relationship) take off 3 points.
  - For each missing key constraint take off 2 points.
  - For each missing total participation take off 2 points.
  - For each missing entity set take off 1 point.
  - For each missing relationship set take off 1 points.
  - For each missing indication of key attribute take off 1 point.
  - For each missing indication of partial key attribute 
                         take off 1 point. 
  - For each missing table, take off 1 point. 
  - For missing assertion (or check) take off 4 points.
  - For each missing primary or foreign key constraint take off 
               0.5 point.
 
 Remark:  
         1) I don't take off any mark for missing attributes of entities.
         2) Students may have different, but correct diagrams or tables, 
            in which case they receive full marks. 


Question 3 and 4 (30 points)
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  The relational agebra and calculus questions have each 5 points. 

  The SQL queries and constraint have each the points indicated 
  on the exam sheet.

In general, I do the following:
   
    - I give 3/4 of the marks if at least half of the solution is there. 
    - Whenever I see that the student has the right idea but the syntax 
      is slightly wrong, I give full marks.
    - I am leniant on the SQL syntax. 
    - For each missing element (attribute, table name, join etc) I take 
      off 1 point, except for missing table (in the FROM clause) where I 
      take off 2 points.
    - If you add unnecessary tables in joins, I take off 1 point.
    - Each missing clause in SQL costs you 1 point. 
    


Question 5
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In case of hesitation, I give you the benefit of dought.