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PORails validation for a has_many association
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  1. PORails validation for a has_many association
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    copied!<p>I am having trouble with validations on a has_many relationship where the children exist, but the parent doesn't. However, when creating/saving the parent object, I want to ensure that specific children (with certain attributes) have already been saved.</p> <p>There is a <code>Parent</code> object that <code>has_many</code> <code>Child</code> objects. The <code>Child</code> objects are persisted into the database first, and thus don't have any reference to the parent. The association structure is:</p> <pre><code>Parent - has_many :children Child - someProperty: string - belongs_to: parent </code></pre> <p>For example, there are three child objects:</p> <pre><code>#1 {someProperty: "bookmark", parent: nil} #2 {someProperty: "history", parent: nil } #2 {someProperty: "window", parent: nil } </code></pre> <p>A parent is valid only if it contains child objects with someProperty <code>history</code> and <code>window</code>.</p> <p>I am setting up the parent inside the controller as:</p> <pre><code>p = Parent.new(params[:data]) for type in %w[bookmark_id history_id window_id] if !params[type].blank? p.children &lt;&lt; Child.find(params[type]) end end // save the parent object p now p.save! </code></pre> <p>When the children are assigned to the parent with <code>&lt;&lt;</code>, they are not saved immediately as the parent's id does not exist. And for the parent to be saved, it must have at least those 2 children. How could I solve this problem? Any input is welcome.</p>
 

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