My first Rails app: choosing the database schema (newbie here)

Rails
1

Hi there people.

After lot of reading regarding how Rails works
(controllers,models,views,routing,templating etc) and doing some
tutorial
apps, I’ve decided to start building my own application. It will be a
real-world app that my and the other members of my team will use.

It will be a project management & collaboration app, crafted to fit
exactly
our needs: We have an online store running so we want to have a place
where
we will be able to post TO-DOs, ideas & messages. Now let’s get to the
point: These are the database tables as of now (I’m ommiting the ideas &
messages tables since they’re similar to the todos):

[ users ]
[ sections ]
[ subsections ]
[ todos ]

The main point is that first of all will be sections, for example “Site
design”, “Marketing & Promotion”, “Checkout process” etc. I might call
this
table Projects instead, not sure about that yet.
Now, a section may (or may not) have one or more subsections. For
example
the “Site design” section may have a “Footer” subsection and a “Logo”
subsection. Inside these subsections (or if there aren’t any, straight
inside the section) there will be to-do lists, messages & ideas.

I hope you get the point by now. Well, now comes the important part, the
associations. These are my initial thoughts which I think are kinda off,
since there’s a problem if I decide to use a seperate table for the
subsections, because the to-dos etc maybe also in a section. So this is
my
question for now: should I have a separate table for subsections or
should
I do it with one table only (sections)? In other words, I want to
implement
a “nested sections” system.

[ sections ] has_many: [ subsections ]
[ subsections ] belongs_to: [sections]

After I solve this issue, the other tables relations would be like this:
[ sections ] (or subsections) has_many: todos
[ todos ] belongs_to: sections

2

Just to be more specific: I want to have parent and child “Sections”. A
section can be a parent section (top-level section) or a child of
another
section, or a child of another child section. Then, to-dos, messages &
ideas can belong either to a parent or to a child category.

For example, consider this hierarchy:

Site design (parent section, doesn’t belong anywhere)
-Footer design
----Footer links styling
----Social media bookmarks
-Header design
----Logo design
----Menu design
Advertising & Promotion
-Social media advertising
----Twitter
----Facebook
-Offline advertisting
etc…

Looking at this table, I think it would be more flexible to have all the
sections in one table and maybe use a “Parent_id” column in the same
table.
Am I missing something?

Thanks in advance.

3

On 1 February 2012 19:10, Agis A. [email protected] wrote:

----Social media bookmarks
Looking at this table, I think it would be more flexible to have all the
sections in one table and maybe use a “Parent_id” column in the same table.
Am I missing something?

Google for
rails self referential
and you will find many links, rails casts and so on that use this
technique. It is very common.

Colin

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4

since there’s a problem if I decide to use a seperate table for the

subsections, because the to-dos etc maybe also in a section. So this is my
question for now: should I have a separate table for subsections or should
I do it with one table only (sections)? In other words, I want to implement
a “nested sections” system.

Colin’s suggestion for using “self referential” techniques is definitely
recommended. Additionally, from your description it sounds like you
could
possibly have "to do"s and other items associated with with a range of
objects in our site. If you do go down this path, you will want to
investigate Rails’ polymorphic relations. This would allow you to have
"to
do"s associated with sections, subsections, articles, orders, accounts,
etc. I’ve used polymorphism to make one “picture” model available for
association with users, articles, posts, products, etc. and it works
pretty
well.

Don