I had a similar issue with a project I was working on and was able to filter the data using named scopes in my models.
Rails 3.0.4/5 docs Named Scope http://api.rubyonrails.org/classes/ActiveRecord/NamedScope/ClassMethods.html B. On Mon, Feb 28, 2011 at 5:08 PM, Peter <[email protected]> wrote: > (Sorry about the lame title, if someone has a better title let me know > and I think I can edit it) > > Hi, > > I have a design question about the best way to enable filtering of > records at runtime, based on criteria that an end user (i.e. an admin) > can set. I'm sure I'm describing that poorly so let me give a semi > contrived example. Let's say I have the following: > 1) a Program model, a User model, and a join table > 2) Users have the ability to enroll in a Program (hence the join > table) > 3) The Program's that they can enroll in (and thus the ones that are > shown to them) are dependent on: > a) Characteristics of the user (for this example let's say sex Male/ > Female, and marital status Married/Single) > b) Admin configuration of the Program (for example Program #1 > requires them to be Male AND Married, Program #2 requires them to be > Female OR Single, etc.) > 4) For 3a this information is collected during signup and at other > types, for 3b the admins create a new program and need to be able to > set the criteria. > > I'm curious the best way to store these criteria? Right now I have a > criteria field on Program that has a templated (in liquid), logical > condition (parsed with treetop). This accomplishes the features > pretty straightforward: read all programs, evaluate each condition > with a hash of the user attributes, show the ones that return true. > > However, this is clearly bad from a performance scalability standpoint > as the whole Program table needs to be read in, which will grow and > grow. I can't figure out a way to make that issue go away since the > (potential) construction of a SQL condition for the query depends on > the particular criteria for a program. > > Any suggestions? > > Thanks, > \Peter > > -- > You received this message because you are subscribed to the Google Groups > "Ruby on Rails: Talk" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/rubyonrails-talk?hl=en. > > -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/rubyonrails-talk?hl=en.
