Changes to clean database for 2.0

[ywarnier]

Replace queries where we use c_id + id instead by only iid.
Remove all fields (c_id +) id in corresponding tables.

• delete track_e_uploads.upload_cours_id (c_id already there)
• delete track_e_hotspot.hotspot_course_code (c_id already there)
• convert track_stored_values_stack.course_id to c_id and change type (varchar to int)
• convert track_stored_values.course_id to c_id and change type
• convert track_e_exercises.session_id from smallint to int
• convert course_category.parent_id from varchar(40) to int
• templates.course_code to template.c_id
• gradebook_category.course_code to c_id
• gradebook_evaluation.course_code to c_id
• gradebook_link.course_code to c_id
• gradebook_result_log.id_result to result_id
• add c_quiz_question_category.session_id
• rename track_e_exercises.exe_weighting to track_e_exercises.max_score
• rename track_e_exercises.exe_result to track_e_exercises.score
• add extra_field.helper_text for adding helper texts under form elements
• alter table gradebook_category add index idx_gb_cat_parent (parent_id);
• alter table gradebook_evaluation add index idx_ge_cat (category_id);
• alter table gradebook_result add index idx_gb_uid_eid (user_id, evaluation_id);
• alter table gradebook_link add index idx_gl_cat (category_id);
• drop course column from personal_agenda table (deprecated)

[jmontoyaa]

add extra_field.comment_text for adding helper texts under form elements

I added the extra_field.description is that the same?

I'm not sure if this is worth it for now:

rename track_e_exercises.exe_weighting to track_e_exercises.max_score
rename track_e_exercises.exe_result to track_e_exercises.score

There are many calls of those fields... are you sure?

[ywarnier]

add extra_field.comment_text for adding helper texts under form elements

I added the extra_field.description is that the same?

I guess. Do you use the extra_field.description field to show the description below the option (like we do in the administration settings)? That's what it should have done for the "comment_text".

I'm not sure if this is worth it for now:
rename track_e_exercises.exe_weighting to track_e_exercises.max_score
rename track_e_exercises.exe_result to track_e_exercises.score
There are many calls of those fields... are you sure?

It's like everything: I think the most we postpone that, the most it's going to bother us. I also think that, because of the very specific name of those fields at the moment (exe_weighting and exe_result) it should be a quick and reliable replacement in the code. The only problem I can see is if another max_score or score field exists in the same queries that we are changing, but if we make sure they all have prefixes, that should work just fine.

[ywarnier]

By the way, what about the other fields, @jmontoyaa ? Did you already change them (c_id etc). Because I think those are much more tricky than weighting.

[jmontoyaa]

Most of the c_id changes were already done in 1.11.x and I finished them in this commit:

09b1417

[jmontoyaa]

Mmm well you proposed "extra_field.description" here:
#2551
So I'm not sure it's the same or not.