docs: collect refreshed mongo-ops wiki site (API-correct overhaul, v0.1.5)

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<span class="md-ellipsis">
02 components
Core Components
</span>
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<input class="md-nav__toggle md-toggle" type="checkbox" id="__toc">
<label class="md-nav__link md-nav__link--active" for="__toc">
@@ -914,6 +916,8 @@
<label class="md-nav__title" for="__toc">
<span class="md-nav__icon md-icon"></span>
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<ul class="md-nav__list" data-md-component="toc" data-md-scrollfix>
<li class="md-nav__item">
<a href="#common-patterns" class="md-nav__link">
<span class="md-ellipsis">
Common Patterns
</span>
</a>
<nav class="md-nav" aria-label="Common Patterns">
<ul class="md-nav__list">
<li class="md-nav__item">
<a href="#pattern-1-service-layer-with-repository" class="md-nav__link">
<span class="md-ellipsis">
Pattern 1: Service Layer with Repository
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</a>
</li>
<li class="md-nav__item">
<li class="md-nav__item">
<a href="#pattern-2-aggregation-pipeline" class="md-nav__link">
<span class="md-ellipsis">
Pattern 2: Aggregation Pipeline
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</a>
</li>
<li class="md-nav__item">
<li class="md-nav__item">
<a href="#pattern-3-bulk-operations" class="md-nav__link">
<span class="md-ellipsis">
Pattern 3: Bulk Operations
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</a>
</li>
</ul>
</nav>
<li class="md-nav__item">
<a href="#pattern-4-transactional-multi-step-write" class="md-nav__link">
<span class="md-ellipsis">
Pattern 4: Transactional Multi-Step Write
</span>
</a>
</li>
<li class="md-nav__item">
<a href="#related" class="md-nav__link">
<span class="md-ellipsis">
Related
</span>
</a>
</li>
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<h1>Common Patterns</h1>
<h2 id="common-patterns">Common Patterns</h2>
<h3 id="pattern-1-service-layer-with-repository">Pattern 1: Service Layer with Repository</h3>
<div class="language-python highlight"><span class="filename">Python</span><pre><span></span><code><a id="__codelineno-0-1" name="__codelineno-0-1" href="#__codelineno-0-1"></a><span class="k">class</span><span class="w"> </span><span class="nc">UserService</span><span class="p">:</span>
<a id="__codelineno-0-2" name="__codelineno-0-2" href="#__codelineno-0-2"></a> <span class="k">def</span><span class="w"> </span><span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">user_repo</span><span class="p">:</span> <span class="n">UserRepository</span><span class="p">):</span>
<a id="__codelineno-0-3" name="__codelineno-0-3" href="#__codelineno-0-3"></a> <span class="bp">self</span><span class="o">.</span><span class="n">user_repo</span> <span class="o">=</span> <span class="n">user_repo</span>
<a id="__codelineno-0-4" name="__codelineno-0-4" href="#__codelineno-0-4"></a>
<a id="__codelineno-0-5" name="__codelineno-0-5" href="#__codelineno-0-5"></a> <span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">register_user</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">username</span><span class="p">:</span> <span class="nb">str</span><span class="p">,</span> <span class="n">email</span><span class="p">:</span> <span class="nb">str</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">User</span><span class="p">:</span>
<a id="__codelineno-0-6" name="__codelineno-0-6" href="#__codelineno-0-6"></a> <span class="c1"># Check if user exists</span>
<a id="__codelineno-0-7" name="__codelineno-0-7" href="#__codelineno-0-7"></a> <span class="n">existing</span> <span class="o">=</span> <span class="k">await</span> <span class="bp">self</span><span class="o">.</span><span class="n">user_repo</span><span class="o">.</span><span class="n">collection</span><span class="o">.</span><span class="n">find_one</span><span class="p">({</span><span class="s2">&quot;email&quot;</span><span class="p">:</span> <span class="n">email</span><span class="p">})</span>
<a id="__codelineno-0-8" name="__codelineno-0-8" href="#__codelineno-0-8"></a> <span class="k">if</span> <span class="n">existing</span><span class="p">:</span>
<a id="__codelineno-0-9" name="__codelineno-0-9" href="#__codelineno-0-9"></a> <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">&quot;Email already exists&quot;</span><span class="p">)</span>
<a id="__codelineno-0-10" name="__codelineno-0-10" href="#__codelineno-0-10"></a>
<a id="__codelineno-0-11" name="__codelineno-0-11" href="#__codelineno-0-11"></a> <span class="c1"># Create user</span>
<a id="__codelineno-0-12" name="__codelineno-0-12" href="#__codelineno-0-12"></a> <span class="n">user</span> <span class="o">=</span> <span class="n">User</span><span class="p">(</span><span class="n">username</span><span class="o">=</span><span class="n">username</span><span class="p">,</span> <span class="n">email</span><span class="o">=</span><span class="n">email</span><span class="p">)</span>
<a id="__codelineno-0-13" name="__codelineno-0-13" href="#__codelineno-0-13"></a> <span class="k">return</span> <span class="k">await</span> <span class="bp">self</span><span class="o">.</span><span class="n">user_repo</span><span class="o">.</span><span class="n">create</span><span class="p">(</span><span class="n">user</span><span class="p">)</span>
<h1 id="common-patterns">Common Patterns</h1>
<p>Reusable code shapes built on <code>BaseRepository</code> and friends.</p>
<hr />
<h2 id="pattern-1-service-layer-with-repository">Pattern 1: Service Layer with Repository</h2>
<p>Keep orchestration out of routes. A service composes one or more repositories and owns the domain rules.</p>
<div class="language-python highlight"><span class="filename">Python</span><pre><span></span><code><a id="__codelineno-0-1" name="__codelineno-0-1" href="#__codelineno-0-1"></a><span class="kn">from</span><span class="w"> </span><span class="nn">mongo_ops</span><span class="w"> </span><span class="kn">import</span> <span class="n">BaseRepository</span><span class="p">,</span> <span class="n">BaseDocument</span>
<a id="__codelineno-0-2" name="__codelineno-0-2" href="#__codelineno-0-2"></a>
<a id="__codelineno-0-3" name="__codelineno-0-3" href="#__codelineno-0-3"></a>
<a id="__codelineno-0-4" name="__codelineno-0-4" href="#__codelineno-0-4"></a><span class="k">class</span><span class="w"> </span><span class="nc">User</span><span class="p">(</span><span class="n">BaseDocument</span><span class="p">):</span>
<a id="__codelineno-0-5" name="__codelineno-0-5" href="#__codelineno-0-5"></a> <span class="n">username</span><span class="p">:</span> <span class="nb">str</span> <span class="o">=</span> <span class="s2">&quot;&quot;</span>
<a id="__codelineno-0-6" name="__codelineno-0-6" href="#__codelineno-0-6"></a> <span class="n">email</span><span class="p">:</span> <span class="nb">str</span> <span class="o">=</span> <span class="s2">&quot;&quot;</span>
<a id="__codelineno-0-7" name="__codelineno-0-7" href="#__codelineno-0-7"></a>
<a id="__codelineno-0-8" name="__codelineno-0-8" href="#__codelineno-0-8"></a>
<a id="__codelineno-0-9" name="__codelineno-0-9" href="#__codelineno-0-9"></a><span class="k">class</span><span class="w"> </span><span class="nc">UserRepository</span><span class="p">(</span><span class="n">BaseRepository</span><span class="p">[</span><span class="n">User</span><span class="p">]):</span>
<a id="__codelineno-0-10" name="__codelineno-0-10" href="#__codelineno-0-10"></a> <span class="k">def</span><span class="w"> </span><span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<a id="__codelineno-0-11" name="__codelineno-0-11" href="#__codelineno-0-11"></a> <span class="nb">super</span><span class="p">()</span><span class="o">.</span><span class="fm">__init__</span><span class="p">(</span><span class="s2">&quot;users&quot;</span><span class="p">,</span> <span class="n">User</span><span class="p">)</span>
<a id="__codelineno-0-12" name="__codelineno-0-12" href="#__codelineno-0-12"></a>
<a id="__codelineno-0-13" name="__codelineno-0-13" href="#__codelineno-0-13"></a> <span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">find_by_email</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">email</span><span class="p">:</span> <span class="nb">str</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">User</span> <span class="o">|</span> <span class="kc">None</span><span class="p">:</span>
<a id="__codelineno-0-14" name="__codelineno-0-14" href="#__codelineno-0-14"></a> <span class="n">doc</span> <span class="o">=</span> <span class="k">await</span> <span class="bp">self</span><span class="o">.</span><span class="n">collection</span><span class="o">.</span><span class="n">find_one</span><span class="p">({</span><span class="s2">&quot;email&quot;</span><span class="p">:</span> <span class="n">email</span><span class="p">})</span>
<a id="__codelineno-0-15" name="__codelineno-0-15" href="#__codelineno-0-15"></a> <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="p">(</span><span class="o">**</span><span class="n">doc</span><span class="p">)</span> <span class="k">if</span> <span class="n">doc</span> <span class="k">else</span> <span class="kc">None</span>
<a id="__codelineno-0-16" name="__codelineno-0-16" href="#__codelineno-0-16"></a>
<a id="__codelineno-0-17" name="__codelineno-0-17" href="#__codelineno-0-17"></a>
<a id="__codelineno-0-18" name="__codelineno-0-18" href="#__codelineno-0-18"></a><span class="k">class</span><span class="w"> </span><span class="nc">UserService</span><span class="p">:</span>
<a id="__codelineno-0-19" name="__codelineno-0-19" href="#__codelineno-0-19"></a> <span class="k">def</span><span class="w"> </span><span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">user_repo</span><span class="p">:</span> <span class="n">UserRepository</span><span class="p">):</span>
<a id="__codelineno-0-20" name="__codelineno-0-20" href="#__codelineno-0-20"></a> <span class="bp">self</span><span class="o">.</span><span class="n">user_repo</span> <span class="o">=</span> <span class="n">user_repo</span>
<a id="__codelineno-0-21" name="__codelineno-0-21" href="#__codelineno-0-21"></a>
<a id="__codelineno-0-22" name="__codelineno-0-22" href="#__codelineno-0-22"></a> <span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">register_user</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">username</span><span class="p">:</span> <span class="nb">str</span><span class="p">,</span> <span class="n">email</span><span class="p">:</span> <span class="nb">str</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="n">User</span><span class="p">:</span>
<a id="__codelineno-0-23" name="__codelineno-0-23" href="#__codelineno-0-23"></a> <span class="k">if</span> <span class="k">await</span> <span class="bp">self</span><span class="o">.</span><span class="n">user_repo</span><span class="o">.</span><span class="n">find_by_email</span><span class="p">(</span><span class="n">email</span><span class="p">):</span>
<a id="__codelineno-0-24" name="__codelineno-0-24" href="#__codelineno-0-24"></a> <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">&quot;Email already exists&quot;</span><span class="p">)</span>
<a id="__codelineno-0-25" name="__codelineno-0-25" href="#__codelineno-0-25"></a> <span class="k">return</span> <span class="k">await</span> <span class="bp">self</span><span class="o">.</span><span class="n">user_repo</span><span class="o">.</span><span class="n">create</span><span class="p">(</span><span class="n">User</span><span class="p">(</span><span class="n">username</span><span class="o">=</span><span class="n">username</span><span class="p">,</span> <span class="n">email</span><span class="o">=</span><span class="n">email</span><span class="p">))</span>
</code></pre></div>
<h3 id="pattern-2-aggregation-pipeline">Pattern 2: Aggregation Pipeline</h3>
<div class="language-python highlight"><span class="filename">Python</span><pre><span></span><code><a id="__codelineno-1-1" name="__codelineno-1-1" href="#__codelineno-1-1"></a><span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">get_user_stats</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">user_id</span><span class="p">:</span> <span class="nb">str</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">dict</span><span class="p">:</span>
<a id="__codelineno-1-2" name="__codelineno-1-2" href="#__codelineno-1-2"></a> <span class="n">pipeline</span> <span class="o">=</span> <span class="p">[</span>
<a id="__codelineno-1-3" name="__codelineno-1-3" href="#__codelineno-1-3"></a> <span class="p">{</span><span class="s2">&quot;$match&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;author_id&quot;</span><span class="p">:</span> <span class="n">user_id</span><span class="p">}},</span>
<a id="__codelineno-1-4" name="__codelineno-1-4" href="#__codelineno-1-4"></a> <span class="p">{</span><span class="s2">&quot;$group&quot;</span><span class="p">:</span> <span class="p">{</span>
<a id="__codelineno-1-5" name="__codelineno-1-5" href="#__codelineno-1-5"></a> <span class="s2">&quot;_id&quot;</span><span class="p">:</span> <span class="kc">None</span><span class="p">,</span>
<a id="__codelineno-1-6" name="__codelineno-1-6" href="#__codelineno-1-6"></a> <span class="s2">&quot;total_posts&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;$sum&quot;</span><span class="p">:</span> <span class="mi">1</span><span class="p">},</span>
<a id="__codelineno-1-7" name="__codelineno-1-7" href="#__codelineno-1-7"></a> <span class="s2">&quot;total_likes&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;$sum&quot;</span><span class="p">:</span> <span class="s2">&quot;$likes&quot;</span><span class="p">}</span>
<a id="__codelineno-1-8" name="__codelineno-1-8" href="#__codelineno-1-8"></a> <span class="p">}}</span>
<a id="__codelineno-1-9" name="__codelineno-1-9" href="#__codelineno-1-9"></a> <span class="p">]</span>
<a id="__codelineno-1-10" name="__codelineno-1-10" href="#__codelineno-1-10"></a> <span class="n">result</span> <span class="o">=</span> <span class="k">await</span> <span class="n">post_repo</span><span class="o">.</span><span class="n">collection</span><span class="o">.</span><span class="n">aggregate</span><span class="p">(</span><span class="n">pipeline</span><span class="p">)</span><span class="o">.</span><span class="n">to_list</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>
<a id="__codelineno-1-11" name="__codelineno-1-11" href="#__codelineno-1-11"></a> <span class="k">return</span> <span class="n">result</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="k">if</span> <span class="n">result</span> <span class="k">else</span> <span class="p">{</span><span class="s2">&quot;total_posts&quot;</span><span class="p">:</span> <span class="mi">0</span><span class="p">,</span> <span class="s2">&quot;total_likes&quot;</span><span class="p">:</span> <span class="mi">0</span><span class="p">}</span>
</code></pre></div>
<h3 id="pattern-3-bulk-operations">Pattern 3: Bulk Operations</h3>
<div class="language-python highlight"><span class="filename">Python</span><pre><span></span><code><a id="__codelineno-2-1" name="__codelineno-2-1" href="#__codelineno-2-1"></a><span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">bulk_update_status</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">ids</span><span class="p">:</span> <span class="n">List</span><span class="p">[</span><span class="nb">str</span><span class="p">],</span> <span class="n">status</span><span class="p">:</span> <span class="nb">str</span><span class="p">):</span>
<a id="__codelineno-2-2" name="__codelineno-2-2" href="#__codelineno-2-2"></a> <span class="kn">from</span><span class="w"> </span><span class="nn">bson</span><span class="w"> </span><span class="kn">import</span> <span class="n">ObjectId</span>
<a id="__codelineno-2-3" name="__codelineno-2-3" href="#__codelineno-2-3"></a> <span class="n">object_ids</span> <span class="o">=</span> <span class="p">[</span><span class="n">ObjectId</span><span class="p">(</span><span class="nb">id</span><span class="p">)</span> <span class="k">for</span> <span class="nb">id</span> <span class="ow">in</span> <span class="n">ids</span><span class="p">]</span>
<a id="__codelineno-2-4" name="__codelineno-2-4" href="#__codelineno-2-4"></a> <span class="k">await</span> <span class="bp">self</span><span class="o">.</span><span class="n">collection</span><span class="o">.</span><span class="n">update_many</span><span class="p">(</span>
<a id="__codelineno-2-5" name="__codelineno-2-5" href="#__codelineno-2-5"></a> <span class="p">{</span><span class="s2">&quot;_id&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;$in&quot;</span><span class="p">:</span> <span class="n">object_ids</span><span class="p">}},</span>
<a id="__codelineno-2-6" name="__codelineno-2-6" href="#__codelineno-2-6"></a> <span class="p">{</span><span class="s2">&quot;$set&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;status&quot;</span><span class="p">:</span> <span class="n">status</span><span class="p">,</span> <span class="s2">&quot;updated_at&quot;</span><span class="p">:</span> <span class="n">datetime</span><span class="o">.</span><span class="n">utcnow</span><span class="p">()}}</span>
<a id="__codelineno-2-7" name="__codelineno-2-7" href="#__codelineno-2-7"></a> <span class="p">)</span>
<blockquote>
<p>Register a unique index on <code>email</code> via <code>ModelRegistry</code> so the race is also caught by <code>DuplicateKeyError</code> — see <a href="../03_use_cases/13_index_creation/">use case 13</a>.</p>
</blockquote>
<hr />
<h2 id="pattern-2-aggregation-pipeline">Pattern 2: Aggregation Pipeline</h2>
<p>Aggregations hit the raw Motor collection — wrap them in a repository method so callers stay at the domain level.</p>
<div class="language-python highlight"><span class="filename">Python</span><pre><span></span><code><a id="__codelineno-1-1" name="__codelineno-1-1" href="#__codelineno-1-1"></a><span class="kn">from</span><span class="w"> </span><span class="nn">mongo_ops</span><span class="w"> </span><span class="kn">import</span> <span class="n">BaseRepository</span><span class="p">,</span> <span class="n">BaseDocument</span>
<a id="__codelineno-1-2" name="__codelineno-1-2" href="#__codelineno-1-2"></a>
<a id="__codelineno-1-3" name="__codelineno-1-3" href="#__codelineno-1-3"></a>
<a id="__codelineno-1-4" name="__codelineno-1-4" href="#__codelineno-1-4"></a><span class="k">class</span><span class="w"> </span><span class="nc">Post</span><span class="p">(</span><span class="n">BaseDocument</span><span class="p">):</span>
<a id="__codelineno-1-5" name="__codelineno-1-5" href="#__codelineno-1-5"></a> <span class="n">author_id</span><span class="p">:</span> <span class="nb">str</span> <span class="o">=</span> <span class="s2">&quot;&quot;</span>
<a id="__codelineno-1-6" name="__codelineno-1-6" href="#__codelineno-1-6"></a> <span class="n">title</span><span class="p">:</span> <span class="nb">str</span> <span class="o">=</span> <span class="s2">&quot;&quot;</span>
<a id="__codelineno-1-7" name="__codelineno-1-7" href="#__codelineno-1-7"></a> <span class="n">likes</span><span class="p">:</span> <span class="nb">int</span> <span class="o">=</span> <span class="mi">0</span>
<a id="__codelineno-1-8" name="__codelineno-1-8" href="#__codelineno-1-8"></a>
<a id="__codelineno-1-9" name="__codelineno-1-9" href="#__codelineno-1-9"></a>
<a id="__codelineno-1-10" name="__codelineno-1-10" href="#__codelineno-1-10"></a><span class="k">class</span><span class="w"> </span><span class="nc">PostRepository</span><span class="p">(</span><span class="n">BaseRepository</span><span class="p">[</span><span class="n">Post</span><span class="p">]):</span>
<a id="__codelineno-1-11" name="__codelineno-1-11" href="#__codelineno-1-11"></a> <span class="k">def</span><span class="w"> </span><span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<a id="__codelineno-1-12" name="__codelineno-1-12" href="#__codelineno-1-12"></a> <span class="nb">super</span><span class="p">()</span><span class="o">.</span><span class="fm">__init__</span><span class="p">(</span><span class="s2">&quot;posts&quot;</span><span class="p">,</span> <span class="n">Post</span><span class="p">)</span>
<a id="__codelineno-1-13" name="__codelineno-1-13" href="#__codelineno-1-13"></a>
<a id="__codelineno-1-14" name="__codelineno-1-14" href="#__codelineno-1-14"></a> <span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">get_user_stats</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">user_id</span><span class="p">:</span> <span class="nb">str</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">dict</span><span class="p">:</span>
<a id="__codelineno-1-15" name="__codelineno-1-15" href="#__codelineno-1-15"></a> <span class="n">pipeline</span> <span class="o">=</span> <span class="p">[</span>
<a id="__codelineno-1-16" name="__codelineno-1-16" href="#__codelineno-1-16"></a> <span class="p">{</span><span class="s2">&quot;$match&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;author_id&quot;</span><span class="p">:</span> <span class="n">user_id</span><span class="p">}},</span>
<a id="__codelineno-1-17" name="__codelineno-1-17" href="#__codelineno-1-17"></a> <span class="p">{</span><span class="s2">&quot;$group&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;_id&quot;</span><span class="p">:</span> <span class="kc">None</span><span class="p">,</span> <span class="s2">&quot;total_posts&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;$sum&quot;</span><span class="p">:</span> <span class="mi">1</span><span class="p">},</span> <span class="s2">&quot;total_likes&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;$sum&quot;</span><span class="p">:</span> <span class="s2">&quot;$likes&quot;</span><span class="p">}}},</span>
<a id="__codelineno-1-18" name="__codelineno-1-18" href="#__codelineno-1-18"></a> <span class="p">]</span>
<a id="__codelineno-1-19" name="__codelineno-1-19" href="#__codelineno-1-19"></a> <span class="n">result</span> <span class="o">=</span> <span class="k">await</span> <span class="bp">self</span><span class="o">.</span><span class="n">collection</span><span class="o">.</span><span class="n">aggregate</span><span class="p">(</span><span class="n">pipeline</span><span class="p">)</span><span class="o">.</span><span class="n">to_list</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>
<a id="__codelineno-1-20" name="__codelineno-1-20" href="#__codelineno-1-20"></a> <span class="k">return</span> <span class="n">result</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="k">if</span> <span class="n">result</span> <span class="k">else</span> <span class="p">{</span><span class="s2">&quot;total_posts&quot;</span><span class="p">:</span> <span class="mi">0</span><span class="p">,</span> <span class="s2">&quot;total_likes&quot;</span><span class="p">:</span> <span class="mi">0</span><span class="p">}</span>
</code></pre></div>
<hr />
<h2 id="pattern-3-bulk-operations">Pattern 3: Bulk Operations</h2>
<p>Multi-document mutation in one call — again wrapped at the repository boundary.</p>
<div class="language-python highlight"><span class="filename">Python</span><pre><span></span><code><a id="__codelineno-2-1" name="__codelineno-2-1" href="#__codelineno-2-1"></a><span class="kn">from</span><span class="w"> </span><span class="nn">datetime</span><span class="w"> </span><span class="kn">import</span> <span class="n">datetime</span>
<a id="__codelineno-2-2" name="__codelineno-2-2" href="#__codelineno-2-2"></a>
<a id="__codelineno-2-3" name="__codelineno-2-3" href="#__codelineno-2-3"></a><span class="kn">from</span><span class="w"> </span><span class="nn">bson</span><span class="w"> </span><span class="kn">import</span> <span class="n">ObjectId</span>
<a id="__codelineno-2-4" name="__codelineno-2-4" href="#__codelineno-2-4"></a><span class="kn">from</span><span class="w"> </span><span class="nn">mongo_ops</span><span class="w"> </span><span class="kn">import</span> <span class="n">BaseRepository</span><span class="p">,</span> <span class="n">BaseDocument</span>
<a id="__codelineno-2-5" name="__codelineno-2-5" href="#__codelineno-2-5"></a>
<a id="__codelineno-2-6" name="__codelineno-2-6" href="#__codelineno-2-6"></a>
<a id="__codelineno-2-7" name="__codelineno-2-7" href="#__codelineno-2-7"></a><span class="k">class</span><span class="w"> </span><span class="nc">Task</span><span class="p">(</span><span class="n">BaseDocument</span><span class="p">):</span>
<a id="__codelineno-2-8" name="__codelineno-2-8" href="#__codelineno-2-8"></a> <span class="n">status</span><span class="p">:</span> <span class="nb">str</span> <span class="o">=</span> <span class="s2">&quot;pending&quot;</span>
<a id="__codelineno-2-9" name="__codelineno-2-9" href="#__codelineno-2-9"></a>
<a id="__codelineno-2-10" name="__codelineno-2-10" href="#__codelineno-2-10"></a>
<a id="__codelineno-2-11" name="__codelineno-2-11" href="#__codelineno-2-11"></a><span class="k">class</span><span class="w"> </span><span class="nc">TaskRepository</span><span class="p">(</span><span class="n">BaseRepository</span><span class="p">[</span><span class="n">Task</span><span class="p">]):</span>
<a id="__codelineno-2-12" name="__codelineno-2-12" href="#__codelineno-2-12"></a> <span class="k">def</span><span class="w"> </span><span class="fm">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<a id="__codelineno-2-13" name="__codelineno-2-13" href="#__codelineno-2-13"></a> <span class="nb">super</span><span class="p">()</span><span class="o">.</span><span class="fm">__init__</span><span class="p">(</span><span class="s2">&quot;tasks&quot;</span><span class="p">,</span> <span class="n">Task</span><span class="p">)</span>
<a id="__codelineno-2-14" name="__codelineno-2-14" href="#__codelineno-2-14"></a>
<a id="__codelineno-2-15" name="__codelineno-2-15" href="#__codelineno-2-15"></a> <span class="k">async</span> <span class="k">def</span><span class="w"> </span><span class="nf">bulk_update_status</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">ids</span><span class="p">:</span> <span class="nb">list</span><span class="p">[</span><span class="nb">str</span><span class="p">],</span> <span class="n">status</span><span class="p">:</span> <span class="nb">str</span><span class="p">)</span> <span class="o">-&gt;</span> <span class="nb">int</span><span class="p">:</span>
<a id="__codelineno-2-16" name="__codelineno-2-16" href="#__codelineno-2-16"></a> <span class="n">object_ids</span> <span class="o">=</span> <span class="p">[</span><span class="n">ObjectId</span><span class="p">(</span><span class="n">i</span><span class="p">)</span> <span class="k">for</span> <span class="n">i</span> <span class="ow">in</span> <span class="n">ids</span><span class="p">]</span>
<a id="__codelineno-2-17" name="__codelineno-2-17" href="#__codelineno-2-17"></a> <span class="n">result</span> <span class="o">=</span> <span class="k">await</span> <span class="bp">self</span><span class="o">.</span><span class="n">collection</span><span class="o">.</span><span class="n">update_many</span><span class="p">(</span>
<a id="__codelineno-2-18" name="__codelineno-2-18" href="#__codelineno-2-18"></a> <span class="p">{</span><span class="s2">&quot;_id&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;$in&quot;</span><span class="p">:</span> <span class="n">object_ids</span><span class="p">}},</span>
<a id="__codelineno-2-19" name="__codelineno-2-19" href="#__codelineno-2-19"></a> <span class="p">{</span><span class="s2">&quot;$set&quot;</span><span class="p">:</span> <span class="p">{</span><span class="s2">&quot;status&quot;</span><span class="p">:</span> <span class="n">status</span><span class="p">,</span> <span class="s2">&quot;updated_at&quot;</span><span class="p">:</span> <span class="n">datetime</span><span class="o">.</span><span class="n">utcnow</span><span class="p">()}},</span>
<a id="__codelineno-2-20" name="__codelineno-2-20" href="#__codelineno-2-20"></a> <span class="p">)</span>
<a id="__codelineno-2-21" name="__codelineno-2-21" href="#__codelineno-2-21"></a> <span class="k">return</span> <span class="n">result</span><span class="o">.</span><span class="n">modified_count</span>
</code></pre></div>
<blockquote>
<p>Bulk/aggregation methods bypass the caching and population layers — keep them deliberate and documented.</p>
</blockquote>
<hr />
<h2 id="pattern-4-transactional-multi-step-write">Pattern 4: Transactional Multi-Step Write</h2>
<p>Cross-collection atomicity with <code>execute_transaction</code> — see <a href="../03_use_cases/12_transaction_helper/">use case 12</a> for the full code.</p>
<div class="language-python highlight"><span class="filename">Python</span><pre><span></span><code><a id="__codelineno-3-1" name="__codelineno-3-1" href="#__codelineno-3-1"></a><span class="n">results</span> <span class="o">=</span> <span class="k">await</span> <span class="n">TransactionManager</span><span class="o">.</span><span class="n">execute_transaction</span><span class="p">([</span><span class="n">op1</span><span class="p">,</span> <span class="n">op2</span><span class="p">,</span> <span class="n">op3</span><span class="p">])</span>
<a id="__codelineno-3-2" name="__codelineno-3-2" href="#__codelineno-3-2"></a><span class="c1"># op1/op2/op3 each receive the shared session; one failure rolls back all.</span>
</code></pre></div>
<hr />
<h2 id="related">Related</h2>
<ul>
<li><a href="../03_use_cases/02_custom_repo/">02 Custom repository</a> · <a href="../03_use_cases/03_transactions/">03 Transactions</a> · <a href="../04_best_practices/">Best Practices</a></li>
</ul>