I read the rails guide on associations and I have also gone through a bunch of questions here on SO and on reddit, but I am just not getting associations conceptually, I think. I have two specific issues I can use as examples from an app I am working on, but I am really just trying to understand what I am doing. Models for these examples:Listbelongs_to :userhas_many :itemsItembelongs_to :listbelongs_to :userUserhas_many :listshas_many :itemsIssue 1: Rendering associationsI know that to show the related associations in a list I can do something like this in my view:Users/show<%= render @list %>Lists/_list <ol> <%= list.name %><%= render list.items %></ol>Items/_item<li><%= item.name %></li>This seems like magic to me. I know I am calling user.list and then list.item, but when there are multiple Lists, how does rails know to separate them with the associated Items underneath? In my head when I see this code I anticipate the following as output:<ol>List(a)List(b)List(c)<li>item(a)</li><li>item(b)</li></ol>What I am trying to do is render each List as a Tab and render the associated Items as the tab content. Ultimately, I have multiple different List type models I want as tabs and matching multiple different Item type models to render as tab content. Edit: I got rid of my second issue, since the post was long and it could be a separate post. Restating the above, how can a take the above collection and render it successfully in tabs where Lists are the tabs and the associated Items render as the content?I am running into issues if I use the code like this in my Users/show:<div class="row"> <div class="col s12"> <ul class="tabs"><%= render @lists %></ul></div><%=render @items %></div>Lists/_list <li class="tab col s3"><a href="#tab_<%=list.id%>"><%= list.name%></a></li>Items/_item <div id="#tab_<%=list.id%>" class="col s12"><%= item.name %></div>If I try this, then my item partial gives me an error, because I can’t call list.id, and it will just render all of my items without displaying them as an associated collection with the Lists. If I nest this and put everything after the <%=render lists %> inside the list partial, then the collections work, but the closing tags end up causing issues. I am not sure how to resolve this.
I edited and updated my post to clarify what I am looking for more specifically. Thank you for the tip about layouts and rendering. I was really caught up on the associations issue. Actually, I had <%= render list.items %> in my code, but I screwed up when making my post from memory.
Thank you very much. I cannot believe I was overlooking something so simple as what you added to your answer. I really, really appreciate it.