Relational DB - Related and not Related

[Cameron Gilroy]

Hi

I'm working on a project that has users and groups, users can be members of a group or they can just be a user - what's going to be the best way to deal with this?

I understand the normal has_many relationship just not sure how to do this one. Will try to post some code snippets tomorrow.

Thanks, Cameron

[Dave Aronson]

On Mon, Jun 24, 2013 at 8:54 AM, Cameron Gilroy <m...@camerongilroy.com> wrote:

> users can be members of a group or they can just be a
> user - what's going to be the best way to deal with this?

has_many :through seems perfect for this, given the many-to-many
nature and the possibility you'll want to have additional info about
the relationship (like when they joined, positions held within the
group, etc.).

-Dave

--
Dave Aronson, the T. Rex of Codosaurus LLC,
secret-cleared freelance software developer
taking contracts in or near NoVa or remote.
See information at http://www.Codosaur.us/.

[Colin Law]

On 24 June 2013 13:54, Cameron Gilroy <m...@camerongilroy.com> wrote:
> Hi
>
> I'm working on a project that has users and groups, users can be members of
> a group or they can just be a user - what's going to be the best way to deal
> with this?

If the user can only be a member of one group then use User belongs_to
group. If a particular member does not belong to a group then just
leave group_id nil. You will obviously have to allow for user.group
== nil in the code where appropriate. If he can belong to many (or
no) groups then use has_many :through as Dave suggested. You can test
user.groups to see if he is in any groups.

[Dave Aronson]

On Mon, Jun 24, 2013 at 10:11 AM, Colin Law <cla...@googlemail.com> wrote:

> If the user can only be a member of one group then use User belongs_to
> group.

Oh, good point. I was assuming (and you know what happens then!) that
a User could belong to many Groups.

[Cameron Gilroy]

Thanks Dave & Colin! That was how I had hoped it would work!

[Cameron Gilroy]

Here is an update, I have it working as only a group or as only a non-group user. I have below the create controller and was wondering what would be the best way to allow associations and non-associated records. Thanks

  def create

    if Group.nil?

      @group = Group.find(params[:group_id])

      @user = @group.users.create(params[:user])

    else

      @user = User.new

      @user.ip_address = request.remote_ip

      @user.ua_string = request.user_agent

      @user = User.new(params[:user])

    end

    respond_to do |format|

      if @user.save && @user.group_id == nil

        format.html { redirect_to "/", notice: 'Thank you for registering!' }

      elsif @user.save && @user.group_id != ""

        format.html { redirect_to group_path(@group.token), notice: 'Thank you for registering!' }

      else

        format.html { render action: "new" }

        format.json { render json: @user.errors, status: :unprocessable_entity }

      end

    end

  end

On Monday, June 24, 2013 10:54:14 PM UTC+10, Cameron Gilroy wrote:

[Dave Aronson]

On Tue, Jun 25, 2013 at 9:55 PM, Cameron Gilroy <m...@camerongilroy.com> wrote:

> respond_to do |format|
> if @user.save && @user.group_id == nil
> format.html { redirect_to "/", notice: 'Thank you for registering!'
> }
> elsif @user.save && @user.group_id != ""
> format.html { redirect_to group_path(@group.token), notice: 'Thank
> you for registering!' }
> else
> format.html { render action: "new" }
> format.json { render json: @user.errors, status:
> :unprocessable_entity }
> end

This will do (or at least try) the save twice, if the user has a
group. I'd recommend:

if it saves
redirect to (if it has a group, the group, else /)
else
give error msg
end

Also, look closely at the way you're checking for a group. The first
option will trigger if the group is nil, the second if it's not ""
(empty string)... but what if it *is* ""? That's neither nil nor
not-"", so it will take the "else" path and pretend like it didn't
save. I suggest you use .blank? (or its inverse, .present?) to tell
if it's there or not. Both nil and "" count as blank (and not
present).

[Colin Law]

On 26 June 2013 02:55, Cameron Gilroy <m...@camerongilroy.com> wrote:
> Here is an update, I have it working as only a group or as only a non-group
> user. I have below the create controller and was wondering what would be the
> best way to allow associations and non-associated records. Thanks
>
> def create
> if Group.nil?

Can you explain what the above line is for?

Colin