Re: First portion of data structure to start from

["Alexey Parshin" <alexeyp@gmail.com>]

Please, consider this structure as a proposition and not as a statement.

2006/4/30, Anatoly Volynets <av@total-knowledge.com>:

Now, I want some clarifications:

Person to Course relation:
  Type: many to many ------ means many people can relate to the same
course, while a person can relate to many courses
  Fields:
    type (student/apprentice/author) ----- so these are fields of the
intermediate table?

1) Yes 2) No, these are the possible values for the field "type" (assumed the referrence to some table of three or more rows)
 

BTW, I am not sure, I remember what exactly an apprentice is here? A
co-author or teacher with some limited rights or a student with some
expanded duties (makes sense if we talk about a group of students)? Any
suggestions?

IMHO,  an apprentice is a trusted student, with some extra rights/duties.

Topic to Required Topics relation:
  Type: one to many ----------- means a topic can be optional or
mandatory? We have related issue in specs: prerequisites for a topic,
but it seems to be much complicated. There can be many
topics/courses/texts/problems/tests/games/other objects pre-required for
the given topic, or course,  or  problem, or  game, or....  Thus we
need  to  provide  one-to-many prerequisite-relation for an object in a
course to objects from Repository (I start to think)?

Means - a topic may require an optional list of other topics. And yes, this is one of the required relations, probably the most important. It means - the person can't start topic if he/she didn't complete the required topics.

Keyword to Topic relation
  Type: one to many
  Fields:
    keyword

One keyword an be used in many topics, courses and so forth, while many
keywords can be used in a course, topic, explanation, etc. So it is
many-to-many and involves many objects, not only topics.

Yes, however if we do it this way - we have more complicated structure with not so much of the gain. It may be done both ways, with some pros and cons.

Explanation to Topic relation
  Type: one to many ---- if one-to-many, then Topic to Explanation:
there supposed to be many explanations for a topic

Explanation to Person relation - I'm not sure we need this at all
  Type: one to many

Explanation
  Fields:
    name,
    reference to source, ---- Why we need this? If an author refers
students to a text from Repository instead of writing his own text (next
field)? I think this situation does not differ from usage of other objects.
    text

Don't you want to know - where (from outside) this text came from? The Bible, a book, etc.. It's optional.

Person
  Fields:
    first name,
    last name,
    address,
    email

Topic
  Property of: course
  Fields:
    title,
    summary,
    problem ------- there can be a lot of problems within a topic

Then we just need another table, "Problem".
    Property of: Topic
    Fields:
       name,
       description

-- 
Alexey Parshin,
http://www.sptk.net