Thanks guys for your help. I went with Villas/Anthony's idea.
On Thursday, 12 July 2012 00:47:06 UTC+2, Najtsirk wrote:
>
> Hello,
>
> I have a database design dilema. I want to do a e-learning system for a
> course. The course soould have severeal lessons, each lesson can be of
> different type.
>
> Let's say we have following model:
>
> #for definiton of each course
> db.define_table('course',
>
> Field('title', 'string'))
>
>
>
>
> #for the video lesson
> db.define_table('video',
>
> Field('title', 'string'),
>
> Field('video_url', 'string'),
>
> Field('course_id', db.course),
>
> Field('weight', 'integer'))
>
>
> #for the tekst lesson
> db.define_table('text',
>
> Field('title', 'string'),
>
> Field('content', 'text'),
>
> Field('course_id', db.course),
>
> Field('weight', 'integer'))
>
>
> I know how to do this with a raw sql using UNION, like:
>
> db.executesql('SELECT title, course_id, weight FROM video UNION SELECT
> title, course_id, weight FROM text WHERE course_id = *some_value* ORDER
> BY weight')
>
> But i wondering if there is any way I can achieve that with DAL? Maybe I
> should design the database model in a different way?
>
> Thank you for your replies, ideas, thoughts..
>
> Kristjan
>
>
>
>
>
>
