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POscope through associations : joins and merge
 

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  1. POscope through associations : joins and merge
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    <p>I have three models : <code>User</code>, <code>Product</code> and <code>Transaction</code>. (<code>Transaction</code> belongs_to both, and <code>User</code> has many <code>Product</code> and <code>Product</code> has many <code>User</code>, through <code>Transaction</code>)</p> <p>In my <code>Transaction</code> model, I have a scope for <code>current</code> transactions :</p> <pre class="lang-rb prettyprint-override"><code>scope :current, -&gt; { where 'transactions.start_date IS NOT NULL AND transactions.end_date IS NULL' } </code></pre> <p>I want to be able to do that in the console, in order to retrieve all the products that have a <code>current</code> transaction :</p> <pre class="lang-rb prettyprint-override"><code>User.first.products.owned </code></pre> <p>In the console, I can make it happen with :</p> <pre class="lang-rb prettyprint-override"><code>User.first.products.merge(Transaction.current.ownership) </code></pre> <h2>First try</h2> <p>So I add this in my <code>Product</code> model :</p> <pre class="lang-rb prettyprint-override"><code>def self.owned merge(Transaction.current.ownership) end </code></pre> <p>I type that in the console :</p> <pre class="lang-rb prettyprint-override"><code>User.first.products.owned </code></pre> <p>But here what's rails console tells me :</p> <pre class="lang-rb prettyprint-override"><code>NoMethodError: undefined method `merge' for #&lt;Class:0x00000004e2c0f8&gt; from /home/flo/.rvm/gems/ruby-2.0.0-p195/gems/activerecord-4.0.0.rc1/lib/active_record/dynamic_matchers.rb:22:in `method_missing' </code></pre> <h2>Other try</h2> <p>If I add this in my <code>Product</code> model :</p> <pre class="lang-rb prettyprint-override"><code>def self.owned joins(:transactions).merge(Transaction.current.ownership) end </code></pre> <p>I type that in the console :</p> <pre class="lang-rb prettyprint-override"><code>User.first.products.owned </code></pre> <p>But it retrieve all products with a current transaction, and not only the first user's products with a current transaction.</p> <p>Do you have any idea of what I'm doing wrong ?</p>
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    1. USFlo Rahl
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    1. COReally don't think it'll work but try out : `scoped.merge(Transaction.current.ownership)` Otherwise I'm afraid you're stuck with `merge` but you can shorten the argument you're sending it.
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      1. UScharlysisto
    2. COI tried that and it returns `DEPRECATION WARNING: Model.scoped is deprecated. Please use Model.all instead.` So I did `all.merge(Transaction.current.ownership)` and then it worked ! Thank you ! Do you want to answer properly to my question, in order to validate it for future viewers ?
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      1. USFlo Rahl
    3. COok happy it worked I was afraid scoped aka all wouldn't hold on the user scope - are you sure it does ? Anyway did wrote the answer :-)
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