doc/api/classes/ActiveRecord/Acts/NestedSet/InstanceMethods.html
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<title>Module: ActiveRecord::Acts::NestedSet::InstanceMethods</title>
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<td><strong>Module</strong></td>
<td class="class-name-in-header">ActiveRecord::Acts::NestedSet::InstanceMethods</td>
</tr>
<tr class="top-aligned-row">
<td><strong>In:</strong></td>
<td>
<a href="../../../../files/vendor/rails/activerecord/lib/active_record/acts/nested_set_rb.html">
vendor/rails/activerecord/lib/active_record/acts/nested_set.rb
</a>
<br />
</td>
</tr>
</table>
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<!-- banner header -->
<div id="bodyContent">
<div id="contextContent">
</div>
<div id="method-list">
<h3 class="section-bar">Methods</h3>
<div class="name-list">
<a href="#M000669">add_child</a>
<a href="#M000672">all_children</a>
<a href="#M000674">before_destroy</a>
<a href="#M000667">child?</a>
<a href="#M000670">children_count</a>
<a href="#M000673">direct_children</a>
<a href="#M000671">full_set</a>
<a href="#M000666">root?</a>
<a href="#M000668">unknown?</a>
</div>
</div>
</div>
<!-- if includes -->
<div id="section">
<!-- if method_list -->
<div id="methods">
<h3 class="section-bar">Public Instance methods</h3>
<div id="method-M000669" class="method-detail">
<a name="M000669"></a>
<div class="method-heading">
<a href="#M000669" class="method-signature">
<span class="method-name">add_child</span><span class="method-args">( child )</span>
</a>
</div>
<div class="method-description">
<p>
Adds a child to this object in the tree. If this object hasn‘t been
initialized, it gets set up as a root node. Otherwise, this method will
update all of the other elements in the tree and shift them to the right,
keeping everything balanced.
</p>
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000669-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000669-source">
<pre>
<span class="ruby-comment cmt"># File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 141</span>
141: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">add_child</span>( <span class="ruby-identifier">child</span> )
142: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">reload</span>
143: <span class="ruby-identifier">child</span>.<span class="ruby-identifier">reload</span>
144:
145: <span class="ruby-keyword kw">if</span> <span class="ruby-identifier">child</span>.<span class="ruby-identifier">root?</span>
146: <span class="ruby-identifier">raise</span> <span class="ruby-value str">"Adding sub-tree isn\'t currently supported"</span>
147: <span class="ruby-keyword kw">else</span>
148: <span class="ruby-keyword kw">if</span> ( (<span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">left_col_name</span>] <span class="ruby-operator">==</span> <span class="ruby-keyword kw">nil</span>) <span class="ruby-operator">||</span> (<span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">right_col_name</span>] <span class="ruby-operator">==</span> <span class="ruby-keyword kw">nil</span>) )
149: <span class="ruby-comment cmt"># Looks like we're now the root node! Woo</span>
150: <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">left_col_name</span>] = <span class="ruby-value">1</span>
151: <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">right_col_name</span>] = <span class="ruby-value">4</span>
152:
153: <span class="ruby-comment cmt"># What do to do about validation?</span>
154: <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">nil</span> <span class="ruby-keyword kw">unless</span> <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">save</span>
155:
156: <span class="ruby-identifier">child</span>[<span class="ruby-identifier">parent_column</span>] = <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">id</span>
157: <span class="ruby-identifier">child</span>[<span class="ruby-identifier">left_col_name</span>] = <span class="ruby-value">2</span>
158: <span class="ruby-identifier">child</span>[<span class="ruby-identifier">right_col_name</span>]= <span class="ruby-value">3</span>
159: <span class="ruby-keyword kw">return</span> <span class="ruby-identifier">child</span>.<span class="ruby-identifier">save</span>
160: <span class="ruby-keyword kw">else</span>
161: <span class="ruby-comment cmt"># OK, we need to add and shift everything else to the right</span>
162: <span class="ruby-identifier">child</span>[<span class="ruby-identifier">parent_column</span>] = <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">id</span>
163: <span class="ruby-identifier">right_bound</span> = <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">right_col_name</span>]
164: <span class="ruby-identifier">child</span>[<span class="ruby-identifier">left_col_name</span>] = <span class="ruby-identifier">right_bound</span>
165: <span class="ruby-identifier">child</span>[<span class="ruby-identifier">right_col_name</span>] = <span class="ruby-identifier">right_bound</span> <span class="ruby-operator">+</span> <span class="ruby-value">1</span>
166: <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">right_col_name</span>] <span class="ruby-operator">+=</span> <span class="ruby-value">2</span>
167: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">class</span>.<span class="ruby-identifier">base_class</span>.<span class="ruby-identifier">transaction</span> {
168: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">class</span>.<span class="ruby-identifier">base_class</span>.<span class="ruby-identifier">update_all</span>( <span class="ruby-node">"#{left_col_name} = (#{left_col_name} + 2)"</span>, <span class="ruby-node">"#{scope_condition} AND #{left_col_name} >= #{right_bound}"</span> )
169: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">class</span>.<span class="ruby-identifier">base_class</span>.<span class="ruby-identifier">update_all</span>( <span class="ruby-node">"#{right_col_name} = (#{right_col_name} + 2)"</span>, <span class="ruby-node">"#{scope_condition} AND #{right_col_name} >= #{right_bound}"</span> )
170: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">save</span>
171: <span class="ruby-identifier">child</span>.<span class="ruby-identifier">save</span>
172: }
173: <span class="ruby-keyword kw">end</span>
174: <span class="ruby-keyword kw">end</span>
175: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div id="method-M000672" class="method-detail">
<a name="M000672"></a>
<div class="method-heading">
<a href="#M000672" class="method-signature">
<span class="method-name">all_children</span><span class="method-args">()</span>
</a>
</div>
<div class="method-description">
<p>
Returns a set of all of its children and nested children
</p>
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000672-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000672-source">
<pre>
<span class="ruby-comment cmt"># File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 188</span>
188: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">all_children</span>
189: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">class</span>.<span class="ruby-identifier">base_class</span>.<span class="ruby-identifier">find</span>(<span class="ruby-identifier">:all</span>, <span class="ruby-identifier">:conditions</span> =<span class="ruby-operator">></span> <span class="ruby-node">"#{scope_condition} AND (#{left_col_name} > #{self[left_col_name]}) and (#{right_col_name} < #{self[right_col_name]})"</span> )
190: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div id="method-M000674" class="method-detail">
<a name="M000674"></a>
<div class="method-heading">
<a href="#M000674" class="method-signature">
<span class="method-name">before_destroy</span><span class="method-args">()</span>
</a>
</div>
<div class="method-description">
<p>
Prunes a branch off of the tree, shifting all of the elements on the right
back to the left so the counts still work.
</p>
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000674-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000674-source">
<pre>
<span class="ruby-comment cmt"># File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 199</span>
199: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">before_destroy</span>
200: <span class="ruby-keyword kw">return</span> <span class="ruby-keyword kw">if</span> <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">right_col_name</span>].<span class="ruby-identifier">nil?</span> <span class="ruby-operator">||</span> <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">left_col_name</span>].<span class="ruby-identifier">nil?</span>
201: <span class="ruby-identifier">dif</span> = <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">right_col_name</span>] <span class="ruby-operator">-</span> <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">left_col_name</span>] <span class="ruby-operator">+</span> <span class="ruby-value">1</span>
202:
203: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">class</span>.<span class="ruby-identifier">base_class</span>.<span class="ruby-identifier">transaction</span> {
204: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">class</span>.<span class="ruby-identifier">base_class</span>.<span class="ruby-identifier">delete_all</span>( <span class="ruby-node">"#{scope_condition} and #{left_col_name} > #{self[left_col_name]} and #{right_col_name} < #{self[right_col_name]}"</span> )
205: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">class</span>.<span class="ruby-identifier">base_class</span>.<span class="ruby-identifier">update_all</span>( <span class="ruby-node">"#{left_col_name} = (#{left_col_name} - #{dif})"</span>, <span class="ruby-node">"#{scope_condition} AND #{left_col_name} >= #{self[right_col_name]}"</span> )
206: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">class</span>.<span class="ruby-identifier">base_class</span>.<span class="ruby-identifier">update_all</span>( <span class="ruby-node">"#{right_col_name} = (#{right_col_name} - #{dif} )"</span>, <span class="ruby-node">"#{scope_condition} AND #{right_col_name} >= #{self[right_col_name]}"</span> )
207: }
208: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div id="method-M000667" class="method-detail">
<a name="M000667"></a>
<div class="method-heading">
<a href="#M000667" class="method-signature">
<span class="method-name">child?</span><span class="method-args">()</span>
</a>
</div>
<div class="method-description">
<p>
Returns true is this is a child node
</p>
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000667-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000667-source">
<pre>
<span class="ruby-comment cmt"># File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 126</span>
126: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">child?</span>
127: <span class="ruby-identifier">parent_id</span> = <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">parent_column</span>]
128: <span class="ruby-operator">!</span>(<span class="ruby-identifier">parent_id</span> <span class="ruby-operator">==</span> <span class="ruby-value">0</span> <span class="ruby-operator">||</span> <span class="ruby-identifier">parent_id</span>.<span class="ruby-identifier">nil?</span>) <span class="ruby-operator">&&</span> (<span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">left_col_name</span>] <span class="ruby-operator">></span> <span class="ruby-value">1</span>) <span class="ruby-operator">&&</span> (<span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">right_col_name</span>] <span class="ruby-operator">></span> <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">left_col_name</span>])
129: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div id="method-M000670" class="method-detail">
<a name="M000670"></a>
<div class="method-heading">
<a href="#M000670" class="method-signature">
<span class="method-name">children_count</span><span class="method-args">()</span>
</a>
</div>
<div class="method-description">
<p>
Returns the number of nested children of this object.
</p>
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000670-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000670-source">
<pre>
<span class="ruby-comment cmt"># File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 178</span>
178: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">children_count</span>
179: <span class="ruby-keyword kw">return</span> (<span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">right_col_name</span>] <span class="ruby-operator">-</span> <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">left_col_name</span>] <span class="ruby-operator">-</span> <span class="ruby-value">1</span>)<span class="ruby-operator">/</span><span class="ruby-value">2</span>
180: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div id="method-M000673" class="method-detail">
<a name="M000673"></a>
<div class="method-heading">
<a href="#M000673" class="method-signature">
<span class="method-name">direct_children</span><span class="method-args">()</span>
</a>
</div>
<div class="method-description">
<p>
Returns a set of only this entry‘s immediate children
</p>
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000673-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000673-source">
<pre>
<span class="ruby-comment cmt"># File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 193</span>
193: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">direct_children</span>
194: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">class</span>.<span class="ruby-identifier">base_class</span>.<span class="ruby-identifier">find</span>(<span class="ruby-identifier">:all</span>, <span class="ruby-identifier">:conditions</span> =<span class="ruby-operator">></span> <span class="ruby-node">"#{scope_condition} and #{parent_column} = #{self.id}"</span>)
195: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div id="method-M000671" class="method-detail">
<a name="M000671"></a>
<div class="method-heading">
<a href="#M000671" class="method-signature">
<span class="method-name">full_set</span><span class="method-args">()</span>
</a>
</div>
<div class="method-description">
<p>
Returns a set of itself and all of its nested children
</p>
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000671-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000671-source">
<pre>
<span class="ruby-comment cmt"># File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 183</span>
183: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">full_set</span>
184: <span class="ruby-keyword kw">self</span>.<span class="ruby-identifier">class</span>.<span class="ruby-identifier">base_class</span>.<span class="ruby-identifier">find</span>(<span class="ruby-identifier">:all</span>, <span class="ruby-identifier">:conditions</span> =<span class="ruby-operator">></span> <span class="ruby-node">"#{scope_condition} AND (#{left_col_name} BETWEEN #{self[left_col_name]} and #{self[right_col_name]})"</span> )
185: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div id="method-M000666" class="method-detail">
<a name="M000666"></a>
<div class="method-heading">
<a href="#M000666" class="method-signature">
<span class="method-name">root?</span><span class="method-args">()</span>
</a>
</div>
<div class="method-description">
<p>
Returns true is this is a root node.
</p>
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000666-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000666-source">
<pre>
<span class="ruby-comment cmt"># File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 120</span>
120: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">root?</span>
121: <span class="ruby-identifier">parent_id</span> = <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">parent_column</span>]
122: (<span class="ruby-identifier">parent_id</span> <span class="ruby-operator">==</span> <span class="ruby-value">0</span> <span class="ruby-operator">||</span> <span class="ruby-identifier">parent_id</span>.<span class="ruby-identifier">nil?</span>) <span class="ruby-operator">&&</span> (<span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">left_col_name</span>] <span class="ruby-operator">==</span> <span class="ruby-value">1</span>) <span class="ruby-operator">&&</span> (<span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">right_col_name</span>] <span class="ruby-operator">></span> <span class="ruby-keyword kw">self</span>[<span class="ruby-identifier">left_col_name</span>])
123: <span class="ruby-keyword kw">end</span>
</pre>
</div>
</div>
</div>
<div id="method-M000668" class="method-detail">
<a name="M000668"></a>
<div class="method-heading">
<a href="#M000668" class="method-signature">
<span class="method-name">unknown?</span><span class="method-args">()</span>
</a>
</div>
<div class="method-description">
<p>
Returns true if we have no idea what this is
</p>
<p><a class="source-toggle" href="#"
onclick="toggleCode('M000668-source');return false;">[Source]</a></p>
<div class="method-source-code" id="M000668-source">
<pre>
<span class="ruby-comment cmt"># File vendor/rails/activerecord/lib/active_record/acts/nested_set.rb, line 132</span>
132: <span class="ruby-keyword kw">def</span> <span class="ruby-identifier">unknown?</span>
133: <span class="ruby-operator">!</span><span class="ruby-identifier">root?</span> <span class="ruby-operator">&&</span> <span class="ruby-operator">!</span><span class="ruby-identifier">child?</span>
134: <span class="ruby-keyword kw">end</span>
</pre>
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