Hi, I'm trying to figure the most efficient way to model the following. I can think of at least two ways to relate the tables but from a client/server perspective! I'm wondering how to best (and elegantly)relate them from an AR perspective. A project has many people, A person can work on many projects at any time, A project has many roles, A role is performed by a person, A person may perform multiple roles, An organisation has many people, An organisation is a stakeholder (God, I hate that word - makes me feel like Dracula surrounded!)in one or more projects, A stakeholder has many roles within a project. So one way I have Projects HABTM Roles Roles HABTM People Organisation Has_Many People An Organisation Belongs_to a Stakeholder A Stakeholder HABTM Projects A Stakeholder Has_Many Roles Or Projects HABTM People, A Project has_many roles, People HABTM Roles, An Organisation has_many People, An Organisation is a Stakeholder in a Project, A Stakeholder has_many Roles in a Project. I guess the outcome I'm after is a way to view this data from various perspectives. For example, I have a project view that presents static project data at the head of the screen with a set of tabs containing partials with forms for editing stuff like e.g. People Acting_For(Stakeholder), Acting_As (Role). Other perspectives would be like seeing which organisations are doing what within any number of projects - that sorta thing. Whatya think? Eric.
on 2006-01-02 02:43
on 2006-01-03 12:40
Eric, I don't comletely understand the definition of the entity Role. Possibly usefull is to remember that when a project is closed or a person is removed (started working for another company) that the data is stil accessible. To simplify this. When a qoute or invoice is generated there's always a copy used of the contacts data. Because when that person doesn't work for a company anymore and is removed I would still want to be able to view the quote/invoice/whatever without getting 'nil' object errors. Furthermore a look on what historical info you might save could possibly help as well on the relationships you want to maintain. Looks like the 2nd one seems good (couldn't say why though). But how does a project have many roles. Doesn't a project have many people who, in there turn, have many roles within a project? I'm on the virge of diving into a similar mather on my internal administration appliation and I must admit this fun stuff to chew on .. :-) Hope (wonder if) it helps. Regards, Gerard. On Monday 02 January 2006 02:10, Eric Sloane tried to type something like: > A person may perform multiple roles, > An Organisation Belongs_to a Stakeholder > A Stakeholder has_many Roles in a Project. > Eric. > > _______________________________________________ > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails -- "Who cares if it doesn't do anything? It was made with our new Triple-Iso-Bifurcated-Krypton-Gate-MOS process ..." My $Grtz =~ Gerard; ~ :wq!
on 2006-01-03 14:40
I might suggest the following (and I am making the asusmption that the relationships between projects, people and roles is unlimited (untested) people_projects_roles (join table between people and projects and roles) ---------- person_id role_id project_id class Project < ActiveRecord::Base has_and_belongs_to_many :people, :join_table => "people_projects_roles" has_and_belongs_to_many :roles, :join_table => "people_projects_roles" end class Person < ActiveRecord::Base has_and_belongs_to_many :projects, :join_table => "people_projects_roles" has_and_belongs_to_many :roles, :join_table => "people_projects_roles" end class Role < ActiveRecord::Base has_and_belongs_to_many :people, :join_table => "people_projects_roles" has_and_belongs_to_many :projects, :join_table => "people_projects_roles" end now, this allows you to do things such as project = Project.find(1) # "my project" # all people who are associated with "my project" (any role) project.people # all roles associated with "my project" project.roles person = Person.find(1) # "John Smith" # all projects assocated with "John Smith" person.projects # all roles assocated with "John Smith" person.roles role = Role.find(1) # "programmer" # all projects with a "programmer" role role.projects # all people with a "progammer" role role.people now say you want to add John as a "manager" (id = 2) role to Project 10 john = Person.find_by_name("John") manager = Role.find_by_name("Manager") project.find(10) with this information, you could do it several different ways...depending on the situation project.people.push_with_attributes(john, :role_id => manager.id) project.roles.push_with_attributes(manager, :person_id => john.id) john.projects.push_with_attributes(project, :role_id => manager.id) john.roles.push_with_attributes(manager, :project_id => project.id) role.projects.push_with_attributes(project, :person_id => john.id) role.people.push_with_attributes(john, :project_id => project.id) each of these accomplish the same thing, they add John as a Manager to Project 10 now, as far as organisation/projects/roles go, that sounds strange (not being critical)...can an organisation have the same roles as a person? i would assume that organisations have different roles than people so you will want to setup a separate "org roles" table to manage those. can an organisation be involved in many projects and can a project have many organisations (stakeholders)? if so, then i would setup another join table between organisations/projects/org roles and follow the same idea as above now, one thing i would be concerned about is corss referencing (not sure the proper term). you have people associated with projects, organisations assocated with projects and people associated with organisations...this can get messy when you want to start limiting who can do based upon their other associations (ie, given a project/organisation association, can only people associated with the same organisation be assocated with that project?) hope this helps.
on 2006-01-03 22:53
Hi Chris, Thanks for your input. You've hit the nail squarely on the head (ouch). The relationship between Projects, Roles and People is to be unlimited for exactly the reasons you have pointed out - brilliantly I might add. As to Organisations - the relationship there is simply to define a broader role - Client, Contractor, etc. that People act_for. In practice this level of flexibility might be overkill - but I want it there - just in case :~) As I said in response to Gerard(to whom I replied before reading your post) - on paper this looks kinda scary Thanks Again, Eric.
on 2006-01-04 00:33
Eric / Chris, @Chris: Cudo's to you Chris! @Eric: Having gone through Chris' email. I must say now it doesn't just look scary on paper .. :-) Being a Rails fan for a couple of weeks I'm not fully up to speed on the proper, and more important failsafe, OO programming. Nevertheless .. I did another post on a model I'm chewing on, on which I would like some reponse. I think, IMHO, I've got the model covered for now (never now what's around the corner). I'm just somewhat insecure on programming around it. But I guess there's just one lesson .. Practice! Should you or Chris have some comments, they would be appreciated. Regards, Gerard. On Tuesday 03 January 2006 22:49, Eric Sloane tried to type something like: > Thanks Again, > > person_id > > "people_projects_roles" has_and_belongs_to_many :roles, :join_table => > > > > > > > > project.people.push_with_attributes(john, :role_id => manager.id > > <http://project.id>) > > many organisations (stakeholders)? if so, then i would setup another > > > > (started working for another company) that the data is stil > > as well on the relationships you want to maintain. > > > > > Hi, > > > A project has many roles, > > > So one way I have > > > Projects HABTM People, > > > People > > > _______________________________________________ > > > > > Rails mailing list > Rails@lists.rubyonrails.org > http://lists.rubyonrails.org/mailman/listinfo/rails -- "Who cares if it doesn't do anything? It was made with our new Triple-Iso-Bifurcated-Krypton-Gate-MOS process ..." My $Grtz =~ Gerard; ~ :wq!
on 2006-01-19 12:32
Hi, If using proposed solution by Chris, have can you paginate for example person.projects with a condition like roles = 'editors'? Rebus