Hi guys!
I am an old procedural programmer learning Rails and object
orientation. :)
I wish to create a little system to help my wife who is a teacher.
The attached PDF file has the preliminary Entity-Relationship model.
I am having a rough time trying to put this model into Rails... :(
Looking at the model I can think about the SQL code necessary. But I
think Ruby and Rails is here to help and speed the development process.
;)
For some examples:
Who teaches at school "x"?
SELECT people.name FROM people WHERE people.id IN
(SELECT team_has_teachers.person_id FROM team_has_teachers WHERE
team_has_teachers.team_id IN
(SELECT teams.id AS team_id FROM teams WHERE teams.school_id =
(SELECT schools.id AS school_id FROM schools WHERE schools.name =
'x')))
Who learns from teacher "x"?
SELECT people.name FROM people WHERE people.id IN
(SELECT team_has_students.person_id FROM team_has_students WHERE
team_has_students.team_id IN
(SELECT team_has_teachers.team_id FROM team_has_teachers WHERE
team_has_teachers.person_id =
(SELECT people.id FROM people WHERE people.name = 'x')))
Who is in team "x"?
SELECT people.name FROM people WHERE people.id IN
(SELECT team_has_students.person_id FROM team_has_students WHERE
team_has_students.team_id IN
(SELECT teams.id FROM teams WHERE teams.name = 'x'))
Any help is welcome!
Best regards,
Mosoleu
Attachments:
http://www.ruby-forum.com/attachment/8356/ER_model.pdf
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