<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" lang=""> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>django.db.models.manager — Django 1.8.19 documentation</title> <link rel="stylesheet" href="../../../../_static/default.css" type="text/css" /> <link rel="stylesheet" href="../../../../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../../../../', VERSION: '1.8.19', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../../../../_static/jquery.js"></script> <script type="text/javascript" src="../../../../_static/underscore.js"></script> <script type="text/javascript" src="../../../../_static/doctools.js"></script> <link rel="index" title="Index" href="../../../../genindex.html" /> <link rel="search" title="Search" href="../../../../search.html" /> <link rel="top" title="Django 1.8.19 documentation" href="../../../../contents.html" /> <link rel="up" title="django" href="../../../django.html" /> <script type="text/javascript" src="../../../../templatebuiltins.js"></script> <script type="text/javascript"> (function($) { if (!django_template_builtins) { // templatebuiltins.js missing, do nothing. return; } $(document).ready(function() { // Hyperlink Django template tags and filters var base = "../../../../ref/templates/builtins.html"; if (base == "#") { // Special case for builtins.html itself base = ""; } // Tags are keywords, class '.k' $("div.highlight\\-html\\+django span.k").each(function(i, elem) { var tagname = $(elem).text(); if ($.inArray(tagname, django_template_builtins.ttags) != -1) { var fragment = tagname.replace(/_/, '-'); $(elem).html("<a href='" + base + "#" + fragment + "'>" + tagname + "</a>"); } }); // Filters are functions, class '.nf' $("div.highlight\\-html\\+django span.nf").each(function(i, elem) { var filtername = $(elem).text(); if ($.inArray(filtername, django_template_builtins.tfilters) != -1) { var fragment = filtername.replace(/_/, '-'); $(elem).html("<a href='" + base + "#" + fragment + "'>" + filtername + "</a>"); } }); }); })(jQuery); </script> </head> <body role="document"> <div class="document"> <div id="custom-doc" class="yui-t6"> <div id="hd"> <h1><a href="../../../../index.html">Django 1.8.19 documentation</a></h1> <div id="global-nav"> <a title="Home page" href="../../../../index.html">Home</a> | <a title="Table of contents" href="../../../../contents.html">Table of contents</a> | <a title="Global index" href="../../../../genindex.html">Index</a> | <a title="Module index" href="../../../../py-modindex.html">Modules</a> </div> <div class="nav"> <a href="../../../index.html" title="Module code" accesskey="U">up</a></div> </div> <div id="bd"> <div id="yui-main"> <div class="yui-b"> <div class="yui-g" id="_modules-django-db-models-manager"> <h1>Source code for django.db.models.manager</h1><div class="highlight"><pre> <span></span><span class="kn">import</span> <span class="nn">copy</span> <span class="kn">import</span> <span class="nn">inspect</span> <span class="kn">from</span> <span class="nn">importlib</span> <span class="k">import</span> <span class="n">import_module</span> <span class="kn">from</span> <span class="nn">django.db</span> <span class="k">import</span> <span class="n">router</span> <span class="kn">from</span> <span class="nn">django.db.models.query</span> <span class="k">import</span> <span class="n">QuerySet</span> <span class="kn">from</span> <span class="nn">django.utils</span> <span class="k">import</span> <span class="n">six</span> <span class="kn">from</span> <span class="nn">django.utils.encoding</span> <span class="k">import</span> <span class="n">python_2_unicode_compatible</span> <span class="k">def</span> <span class="nf">ensure_default_manager</span><span class="p">(</span><span class="n">cls</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Ensures that a Model subclass contains a default manager and sets the</span> <span class="sd"> _default_manager attribute on the class. Also sets up the _base_manager</span> <span class="sd"> points to a plain Manager instance (which could be the same as</span> <span class="sd"> _default_manager if it's not a subclass of Manager).</span> <span class="sd"> """</span> <span class="k">if</span> <span class="n">cls</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">abstract</span><span class="p">:</span> <span class="nb">setattr</span><span class="p">(</span><span class="n">cls</span><span class="p">,</span> <span class="s1">'objects'</span><span class="p">,</span> <span class="n">AbstractManagerDescriptor</span><span class="p">(</span><span class="n">cls</span><span class="p">))</span> <span class="k">return</span> <span class="k">elif</span> <span class="n">cls</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">swapped</span><span class="p">:</span> <span class="nb">setattr</span><span class="p">(</span><span class="n">cls</span><span class="p">,</span> <span class="s1">'objects'</span><span class="p">,</span> <span class="n">SwappedManagerDescriptor</span><span class="p">(</span><span class="n">cls</span><span class="p">))</span> <span class="k">return</span> <span class="k">if</span> <span class="ow">not</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">cls</span><span class="p">,</span> <span class="s1">'_default_manager'</span><span class="p">,</span> <span class="kc">None</span><span class="p">):</span> <span class="k">if</span> <span class="nb">any</span><span class="p">(</span><span class="n">f</span><span class="o">.</span><span class="n">name</span> <span class="o">==</span> <span class="s1">'objects'</span> <span class="k">for</span> <span class="n">f</span> <span class="ow">in</span> <span class="n">cls</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">fields</span><span class="p">):</span> <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span> <span class="s2">"Model </span><span class="si">%s</span><span class="s2"> must specify a custom Manager, because it has a "</span> <span class="s2">"field named 'objects'"</span> <span class="o">%</span> <span class="n">cls</span><span class="o">.</span><span class="n">__name__</span> <span class="p">)</span> <span class="c1"># Create the default manager, if needed.</span> <span class="n">cls</span><span class="o">.</span><span class="n">add_to_class</span><span class="p">(</span><span class="s1">'objects'</span><span class="p">,</span> <span class="n">Manager</span><span class="p">())</span> <span class="n">cls</span><span class="o">.</span><span class="n">_base_manager</span> <span class="o">=</span> <span class="n">cls</span><span class="o">.</span><span class="n">objects</span> <span class="k">elif</span> <span class="ow">not</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">cls</span><span class="p">,</span> <span class="s1">'_base_manager'</span><span class="p">,</span> <span class="kc">None</span><span class="p">):</span> <span class="n">default_mgr</span> <span class="o">=</span> <span class="n">cls</span><span class="o">.</span><span class="n">_default_manager</span><span class="o">.</span><span class="n">__class__</span> <span class="k">if</span> <span class="p">(</span><span class="n">default_mgr</span> <span class="ow">is</span> <span class="n">Manager</span> <span class="ow">or</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">default_mgr</span><span class="p">,</span> <span class="s2">"use_for_related_fields"</span><span class="p">,</span> <span class="kc">False</span><span class="p">)):</span> <span class="n">cls</span><span class="o">.</span><span class="n">_base_manager</span> <span class="o">=</span> <span class="n">cls</span><span class="o">.</span><span class="n">_default_manager</span> <span class="k">else</span><span class="p">:</span> <span class="c1"># Default manager isn't a plain Manager class, or a suitable</span> <span class="c1"># replacement, so we walk up the base class hierarchy until we hit</span> <span class="c1"># something appropriate.</span> <span class="k">for</span> <span class="n">base_class</span> <span class="ow">in</span> <span class="n">default_mgr</span><span class="o">.</span><span class="n">mro</span><span class="p">()[</span><span class="mi">1</span><span class="p">:]:</span> <span class="k">if</span> <span class="p">(</span><span class="n">base_class</span> <span class="ow">is</span> <span class="n">Manager</span> <span class="ow">or</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">base_class</span><span class="p">,</span> <span class="s2">"use_for_related_fields"</span><span class="p">,</span> <span class="kc">False</span><span class="p">)):</span> <span class="n">cls</span><span class="o">.</span><span class="n">add_to_class</span><span class="p">(</span><span class="s1">'_base_manager'</span><span class="p">,</span> <span class="n">base_class</span><span class="p">())</span> <span class="k">return</span> <span class="k">raise</span> <span class="ne">AssertionError</span><span class="p">(</span> <span class="s2">"Should never get here. Please report a bug, including your "</span> <span class="s2">"model and model manager setup."</span> <span class="p">)</span> <span class="nd">@python_2_unicode_compatible</span> <span class="k">class</span> <span class="nc">BaseManager</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> <span class="c1"># Tracks each time a Manager instance is created. Used to retain order.</span> <span class="n">creation_counter</span> <span class="o">=</span> <span class="mi">0</span> <span class="c1">#: If set to True the manager will be serialized into migrations and will</span> <span class="c1">#: thus be available in e.g. RunPython operations</span> <span class="n">use_in_migrations</span> <span class="o">=</span> <span class="kc">False</span> <span class="k">def</span> <span class="nf">__new__</span><span class="p">(</span><span class="n">cls</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span> <span class="c1"># We capture the arguments to make returning them trivial</span> <span class="n">obj</span> <span class="o">=</span> <span class="nb">super</span><span class="p">(</span><span class="n">BaseManager</span><span class="p">,</span> <span class="n">cls</span><span class="p">)</span><span class="o">.</span><span class="n">__new__</span><span class="p">(</span><span class="n">cls</span><span class="p">)</span> <span class="n">obj</span><span class="o">.</span><span class="n">_constructor_args</span> <span class="o">=</span> <span class="p">(</span><span class="n">args</span><span class="p">,</span> <span class="n">kwargs</span><span class="p">)</span> <span class="k">return</span> <span class="n">obj</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="nb">super</span><span class="p">(</span><span class="n">BaseManager</span><span class="p">,</span> <span class="bp">self</span><span class="p">)</span><span class="o">.</span><span class="n">__init__</span><span class="p">()</span> <span class="bp">self</span><span class="o">.</span><span class="n">_set_creation_counter</span><span class="p">()</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="kc">None</span> <span class="bp">self</span><span class="o">.</span><span class="n">name</span> <span class="o">=</span> <span class="kc">None</span> <span class="bp">self</span><span class="o">.</span><span class="n">_inherited</span> <span class="o">=</span> <span class="kc">False</span> <span class="bp">self</span><span class="o">.</span><span class="n">_db</span> <span class="o">=</span> <span class="kc">None</span> <span class="bp">self</span><span class="o">.</span><span class="n">_hints</span> <span class="o">=</span> <span class="p">{}</span> <span class="k">def</span> <span class="nf">__str__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="sd">""" Return "app_label.model_label.manager_name". """</span> <span class="n">model</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="n">app</span> <span class="o">=</span> <span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">app_label</span> <span class="k">return</span> <span class="s1">'</span><span class="si">%s</span><span class="s1">.</span><span class="si">%s</span><span class="s1">.</span><span class="si">%s</span><span class="s1">'</span> <span class="o">%</span> <span class="p">(</span><span class="n">app</span><span class="p">,</span> <span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">object_name</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">name</span><span class="p">)</span> <span class="k">def</span> <span class="nf">deconstruct</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Returns a 5-tuple of the form (as_manager (True), manager_class,</span> <span class="sd"> queryset_class, args, kwargs).</span> <span class="sd"> Raises a ValueError if the manager is dynamically generated.</span> <span class="sd"> """</span> <span class="n">qs_class</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">_queryset_class</span> <span class="k">if</span> <span class="nb">getattr</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="s1">'_built_with_as_manager'</span><span class="p">,</span> <span class="kc">False</span><span class="p">):</span> <span class="c1"># using MyQuerySet.as_manager()</span> <span class="k">return</span> <span class="p">(</span> <span class="kc">True</span><span class="p">,</span> <span class="c1"># as_manager</span> <span class="kc">None</span><span class="p">,</span> <span class="c1"># manager_class</span> <span class="s1">'</span><span class="si">%s</span><span class="s1">.</span><span class="si">%s</span><span class="s1">'</span> <span class="o">%</span> <span class="p">(</span><span class="n">qs_class</span><span class="o">.</span><span class="n">__module__</span><span class="p">,</span> <span class="n">qs_class</span><span class="o">.</span><span class="n">__name__</span><span class="p">),</span> <span class="c1"># qs_class</span> <span class="kc">None</span><span class="p">,</span> <span class="c1"># args</span> <span class="kc">None</span><span class="p">,</span> <span class="c1"># kwargs</span> <span class="p">)</span> <span class="k">else</span><span class="p">:</span> <span class="n">module_name</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">__module__</span> <span class="n">name</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">__class__</span><span class="o">.</span><span class="n">__name__</span> <span class="c1"># Make sure it's actually there and not an inner class</span> <span class="n">module</span> <span class="o">=</span> <span class="n">import_module</span><span class="p">(</span><span class="n">module_name</span><span class="p">)</span> <span class="k">if</span> <span class="ow">not</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">module</span><span class="p">,</span> <span class="n">name</span><span class="p">):</span> <span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span> <span class="s2">"Could not find manager </span><span class="si">%s</span><span class="s2"> in </span><span class="si">%s</span><span class="s2">.</span><span class="se">\n</span><span class="s2">"</span> <span class="s2">"Please note that you need to inherit from managers you "</span> <span class="s2">"dynamically generated with 'from_queryset()'."</span> <span class="o">%</span> <span class="p">(</span><span class="n">name</span><span class="p">,</span> <span class="n">module_name</span><span class="p">)</span> <span class="p">)</span> <span class="k">return</span> <span class="p">(</span> <span class="kc">False</span><span class="p">,</span> <span class="c1"># as_manager</span> <span class="s1">'</span><span class="si">%s</span><span class="s1">.</span><span class="si">%s</span><span class="s1">'</span> <span class="o">%</span> <span class="p">(</span><span class="n">module_name</span><span class="p">,</span> <span class="n">name</span><span class="p">),</span> <span class="c1"># manager_class</span> <span class="kc">None</span><span class="p">,</span> <span class="c1"># qs_class</span> <span class="bp">self</span><span class="o">.</span><span class="n">_constructor_args</span><span class="p">[</span><span class="mi">0</span><span class="p">],</span> <span class="c1"># args</span> <span class="bp">self</span><span class="o">.</span><span class="n">_constructor_args</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="c1"># kwargs</span> <span class="p">)</span> <span class="k">def</span> <span class="nf">check</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span> <span class="k">return</span> <span class="p">[]</span> <span class="nd">@classmethod</span> <span class="k">def</span> <span class="nf">_get_queryset_methods</span><span class="p">(</span><span class="n">cls</span><span class="p">,</span> <span class="n">queryset_class</span><span class="p">):</span> <span class="k">def</span> <span class="nf">create_method</span><span class="p">(</span><span class="n">name</span><span class="p">,</span> <span class="n">method</span><span class="p">):</span> <span class="k">def</span> <span class="nf">manager_method</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">):</span> <span class="k">return</span> <span class="nb">getattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">get_queryset</span><span class="p">(),</span> <span class="n">name</span><span class="p">)(</span><span class="o">*</span><span class="n">args</span><span class="p">,</span> <span class="o">**</span><span class="n">kwargs</span><span class="p">)</span> <span class="n">manager_method</span><span class="o">.</span><span class="n">__name__</span> <span class="o">=</span> <span class="n">method</span><span class="o">.</span><span class="n">__name__</span> <span class="n">manager_method</span><span class="o">.</span><span class="n">__doc__</span> <span class="o">=</span> <span class="n">method</span><span class="o">.</span><span class="n">__doc__</span> <span class="k">return</span> <span class="n">manager_method</span> <span class="n">new_methods</span> <span class="o">=</span> <span class="p">{}</span> <span class="c1"># Refs http://bugs.python.org/issue1785.</span> <span class="n">predicate</span> <span class="o">=</span> <span class="n">inspect</span><span class="o">.</span><span class="n">isfunction</span> <span class="k">if</span> <span class="n">six</span><span class="o">.</span><span class="n">PY3</span> <span class="k">else</span> <span class="n">inspect</span><span class="o">.</span><span class="n">ismethod</span> <span class="k">for</span> <span class="n">name</span><span class="p">,</span> <span class="n">method</span> <span class="ow">in</span> <span class="n">inspect</span><span class="o">.</span><span class="n">getmembers</span><span class="p">(</span><span class="n">queryset_class</span><span class="p">,</span> <span class="n">predicate</span><span class="o">=</span><span class="n">predicate</span><span class="p">):</span> <span class="c1"># Only copy missing methods.</span> <span class="k">if</span> <span class="nb">hasattr</span><span class="p">(</span><span class="n">cls</span><span class="p">,</span> <span class="n">name</span><span class="p">):</span> <span class="k">continue</span> <span class="c1"># Only copy public methods or methods with the attribute `queryset_only=False`.</span> <span class="n">queryset_only</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">method</span><span class="p">,</span> <span class="s1">'queryset_only'</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span> <span class="k">if</span> <span class="n">queryset_only</span> <span class="ow">or</span> <span class="p">(</span><span class="n">queryset_only</span> <span class="ow">is</span> <span class="kc">None</span> <span class="ow">and</span> <span class="n">name</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="s1">'_'</span><span class="p">)):</span> <span class="k">continue</span> <span class="c1"># Copy the method onto the manager.</span> <span class="n">new_methods</span><span class="p">[</span><span class="n">name</span><span class="p">]</span> <span class="o">=</span> <span class="n">create_method</span><span class="p">(</span><span class="n">name</span><span class="p">,</span> <span class="n">method</span><span class="p">)</span> <span class="k">return</span> <span class="n">new_methods</span> <span class="nd">@classmethod</span> <span class="k">def</span> <span class="nf">from_queryset</span><span class="p">(</span><span class="n">cls</span><span class="p">,</span> <span class="n">queryset_class</span><span class="p">,</span> <span class="n">class_name</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> <span class="k">if</span> <span class="n">class_name</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span> <span class="n">class_name</span> <span class="o">=</span> <span class="s1">'</span><span class="si">%s</span><span class="s1">From</span><span class="si">%s</span><span class="s1">'</span> <span class="o">%</span> <span class="p">(</span><span class="n">cls</span><span class="o">.</span><span class="n">__name__</span><span class="p">,</span> <span class="n">queryset_class</span><span class="o">.</span><span class="n">__name__</span><span class="p">)</span> <span class="n">class_dict</span> <span class="o">=</span> <span class="p">{</span> <span class="s1">'_queryset_class'</span><span class="p">:</span> <span class="n">queryset_class</span><span class="p">,</span> <span class="p">}</span> <span class="n">class_dict</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="n">cls</span><span class="o">.</span><span class="n">_get_queryset_methods</span><span class="p">(</span><span class="n">queryset_class</span><span class="p">))</span> <span class="k">return</span> <span class="nb">type</span><span class="p">(</span><span class="n">class_name</span><span class="p">,</span> <span class="p">(</span><span class="n">cls</span><span class="p">,),</span> <span class="n">class_dict</span><span class="p">)</span> <span class="k">def</span> <span class="nf">contribute_to_class</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">,</span> <span class="n">name</span><span class="p">):</span> <span class="c1"># TODO: Use weakref because of possible memory leak / circular reference.</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="n">model</span> <span class="k">if</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">name</span><span class="p">:</span> <span class="bp">self</span><span class="o">.</span><span class="n">name</span> <span class="o">=</span> <span class="n">name</span> <span class="c1"># Only contribute the manager if the model is concrete</span> <span class="k">if</span> <span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">abstract</span><span class="p">:</span> <span class="nb">setattr</span><span class="p">(</span><span class="n">model</span><span class="p">,</span> <span class="n">name</span><span class="p">,</span> <span class="n">AbstractManagerDescriptor</span><span class="p">(</span><span class="n">model</span><span class="p">))</span> <span class="k">elif</span> <span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">swapped</span><span class="p">:</span> <span class="nb">setattr</span><span class="p">(</span><span class="n">model</span><span class="p">,</span> <span class="n">name</span><span class="p">,</span> <span class="n">SwappedManagerDescriptor</span><span class="p">(</span><span class="n">model</span><span class="p">))</span> <span class="k">else</span><span class="p">:</span> <span class="c1"># if not model._meta.abstract and not model._meta.swapped:</span> <span class="nb">setattr</span><span class="p">(</span><span class="n">model</span><span class="p">,</span> <span class="n">name</span><span class="p">,</span> <span class="n">ManagerDescriptor</span><span class="p">(</span><span class="bp">self</span><span class="p">))</span> <span class="k">if</span> <span class="p">(</span><span class="ow">not</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">model</span><span class="p">,</span> <span class="s1">'_default_manager'</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span> <span class="ow">or</span> <span class="bp">self</span><span class="o">.</span><span class="n">creation_counter</span> <span class="o"><</span> <span class="n">model</span><span class="o">.</span><span class="n">_default_manager</span><span class="o">.</span><span class="n">creation_counter</span><span class="p">):</span> <span class="n">model</span><span class="o">.</span><span class="n">_default_manager</span> <span class="o">=</span> <span class="bp">self</span> <span class="n">abstract</span> <span class="o">=</span> <span class="kc">False</span> <span class="k">if</span> <span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">abstract</span> <span class="ow">or</span> <span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">_inherited</span> <span class="ow">and</span> <span class="ow">not</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">proxy</span><span class="p">):</span> <span class="n">abstract</span> <span class="o">=</span> <span class="kc">True</span> <span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">managers</span><span class="o">.</span><span class="n">append</span><span class="p">((</span><span class="bp">self</span><span class="o">.</span><span class="n">creation_counter</span><span class="p">,</span> <span class="bp">self</span><span class="p">,</span> <span class="n">abstract</span><span class="p">))</span> <span class="k">def</span> <span class="nf">_set_creation_counter</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Sets the creation counter value for this instance and increments the</span> <span class="sd"> class-level copy.</span> <span class="sd"> """</span> <span class="bp">self</span><span class="o">.</span><span class="n">creation_counter</span> <span class="o">=</span> <span class="n">BaseManager</span><span class="o">.</span><span class="n">creation_counter</span> <span class="n">BaseManager</span><span class="o">.</span><span class="n">creation_counter</span> <span class="o">+=</span> <span class="mi">1</span> <span class="k">def</span> <span class="nf">_copy_to_model</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Makes a copy of the manager and assigns it to 'model', which should be</span> <span class="sd"> a child of the existing model (used when inheriting a manager from an</span> <span class="sd"> abstract base class).</span> <span class="sd"> """</span> <span class="k">assert</span> <span class="nb">issubclass</span><span class="p">(</span><span class="n">model</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="p">)</span> <span class="n">mgr</span> <span class="o">=</span> <span class="n">copy</span><span class="o">.</span><span class="n">copy</span><span class="p">(</span><span class="bp">self</span><span class="p">)</span> <span class="n">mgr</span><span class="o">.</span><span class="n">_set_creation_counter</span><span class="p">()</span> <span class="n">mgr</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="n">model</span> <span class="n">mgr</span><span class="o">.</span><span class="n">_inherited</span> <span class="o">=</span> <span class="kc">True</span> <span class="k">return</span> <span class="n">mgr</span> <span class="k">def</span> <span class="nf">db_manager</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">using</span><span class="o">=</span><span class="kc">None</span><span class="p">,</span> <span class="n">hints</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> <span class="n">obj</span> <span class="o">=</span> <span class="n">copy</span><span class="o">.</span><span class="n">copy</span><span class="p">(</span><span class="bp">self</span><span class="p">)</span> <span class="n">obj</span><span class="o">.</span><span class="n">_db</span> <span class="o">=</span> <span class="n">using</span> <span class="ow">or</span> <span class="bp">self</span><span class="o">.</span><span class="n">_db</span> <span class="n">obj</span><span class="o">.</span><span class="n">_hints</span> <span class="o">=</span> <span class="n">hints</span> <span class="ow">or</span> <span class="bp">self</span><span class="o">.</span><span class="n">_hints</span> <span class="k">return</span> <span class="n">obj</span> <span class="nd">@property</span> <span class="k">def</span> <span class="nf">db</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_db</span> <span class="ow">or</span> <span class="n">router</span><span class="o">.</span><span class="n">db_for_read</span><span class="p">(</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="bp">self</span><span class="o">.</span><span class="n">_hints</span><span class="p">)</span> <span class="c1">#######################</span> <span class="c1"># PROXIES TO QUERYSET #</span> <span class="c1">#######################</span> <span class="k">def</span> <span class="nf">get_queryset</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="sd">"""</span> <span class="sd"> Returns a new QuerySet object. Subclasses can override this method to</span> <span class="sd"> easily customize the behavior of the Manager.</span> <span class="sd"> """</span> <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">_queryset_class</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="p">,</span> <span class="n">using</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_db</span><span class="p">,</span> <span class="n">hints</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">_hints</span><span class="p">)</span> <span class="k">def</span> <span class="nf">all</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="c1"># We can't proxy this method through the `QuerySet` like we do for the</span> <span class="c1"># rest of the `QuerySet` methods. This is because `QuerySet.all()`</span> <span class="c1"># works by creating a "copy" of the current queryset and in making said</span> <span class="c1"># copy, all the cached `prefetch_related` lookups are lost. See the</span> <span class="c1"># implementation of `RelatedManager.get_queryset()` for a better</span> <span class="c1"># understanding of how this comes into play.</span> <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">get_queryset</span><span class="p">()</span> <span class="k">def</span> <span class="nf">__eq__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">other</span><span class="p">):</span> <span class="k">return</span> <span class="p">(</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">other</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">__class__</span><span class="p">)</span> <span class="ow">and</span> <span class="bp">self</span><span class="o">.</span><span class="n">_constructor_args</span> <span class="o">==</span> <span class="n">other</span><span class="o">.</span><span class="n">_constructor_args</span> <span class="p">)</span> <span class="k">def</span> <span class="nf">__ne__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">other</span><span class="p">):</span> <span class="k">return</span> <span class="ow">not</span> <span class="p">(</span><span class="bp">self</span> <span class="o">==</span> <span class="n">other</span><span class="p">)</span> <span class="k">def</span> <span class="nf">__hash__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="k">return</span> <span class="nb">id</span><span class="p">(</span><span class="bp">self</span><span class="p">)</span> <div class="viewcode-block" id="Manager"><a class="viewcode-back" href="../../../../topics/db/managers.html#django.db.models.Manager">[docs]</a><span class="k">class</span> <span class="nc">Manager</span><span class="p">(</span><span class="n">BaseManager</span><span class="o">.</span><span class="n">from_queryset</span><span class="p">(</span><span class="n">QuerySet</span><span class="p">)):</span> <span class="k">pass</span></div> <span class="k">class</span> <span class="nc">ManagerDescriptor</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> <span class="c1"># This class ensures managers aren't accessible via model instances.</span> <span class="c1"># For example, Poll.objects works, but poll_obj.objects raises AttributeError.</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">manager</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">manager</span> <span class="o">=</span> <span class="n">manager</span> <span class="k">def</span> <span class="nf">__get__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">instance</span><span class="p">,</span> <span class="nb">type</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> <span class="k">if</span> <span class="n">instance</span> <span class="ow">is</span> <span class="ow">not</span> <span class="kc">None</span><span class="p">:</span> <span class="k">raise</span> <span class="ne">AttributeError</span><span class="p">(</span><span class="s2">"Manager isn't accessible via </span><span class="si">%s</span><span class="s2"> instances"</span> <span class="o">%</span> <span class="nb">type</span><span class="o">.</span><span class="n">__name__</span><span class="p">)</span> <span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">manager</span> <span class="k">class</span> <span class="nc">AbstractManagerDescriptor</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> <span class="c1"># This class provides a better error message when you try to access a</span> <span class="c1"># manager on an abstract model.</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="n">model</span> <span class="k">def</span> <span class="nf">__get__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">instance</span><span class="p">,</span> <span class="nb">type</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> <span class="k">raise</span> <span class="ne">AttributeError</span><span class="p">(</span><span class="s2">"Manager isn't available; </span><span class="si">%s</span><span class="s2"> is abstract"</span> <span class="o">%</span> <span class="p">(</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">object_name</span><span class="p">,</span> <span class="p">))</span> <span class="k">class</span> <span class="nc">SwappedManagerDescriptor</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span> <span class="c1"># This class provides a better error message when you try to access a</span> <span class="c1"># manager on a swapped model.</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">):</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="n">model</span> <span class="k">def</span> <span class="nf">__get__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">instance</span><span class="p">,</span> <span class="nb">type</span><span class="o">=</span><span class="kc">None</span><span class="p">):</span> <span class="k">raise</span> <span class="ne">AttributeError</span><span class="p">(</span><span class="s2">"Manager isn't available; </span><span class="si">%s</span><span class="s2"> has been swapped for '</span><span class="si">%s</span><span class="s2">'"</span> <span class="o">%</span> <span class="p">(</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">object_name</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span><span class="o">.</span><span class="n">_meta</span><span class="o">.</span><span class="n">swapped</span> <span class="p">))</span> <span class="k">class</span> <span class="nc">EmptyManager</span><span class="p">(</span><span class="n">Manager</span><span class="p">):</span> <span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">model</span><span class="p">):</span> <span class="nb">super</span><span class="p">(</span><span class="n">EmptyManager</span><span class="p">,</span> <span class="bp">self</span><span class="p">)</span><span class="o">.</span><span class="n">__init__</span><span class="p">()</span> <span class="bp">self</span><span class="o">.</span><span class="n">model</span> <span class="o">=</span> <span class="n">model</span> <span class="k">def</span> <span class="nf">get_queryset</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span> <span class="k">return</span> <span class="nb">super</span><span class="p">(</span><span class="n">EmptyManager</span><span class="p">,</span> <span class="bp">self</span><span class="p">)</span><span class="o">.</span><span class="n">get_queryset</span><span class="p">()</span><span class="o">.</span><span class="n">none</span><span class="p">()</span> </pre></div> </div> </div> </div> <div class="yui-b" id="sidebar"> <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> <div class="sphinxsidebarwrapper"> <h3>Browse</h3> <ul> </ul> <h3>You are here:</h3> <ul> <li> <a href="../../../../index.html">Django 1.8.19 documentation</a> <ul><li><a href="../../../index.html">Module code</a> <ul><li><a href="../../../django.html">django</a> <ul><li>django.db.models.manager</li></ul> </li></ul></li></ul> </li> </ul> <div id="searchbox" style="display: none" role="search"> <h3>Quick search</h3> <form class="search" action="../../../../search.html" method="get"> <div><input type="text" name="q" /></div> <div><input type="submit" value="Go" /></div> <input type="hidden" name="check_keywords" value="yes" /> <input type="hidden" name="area" value="default" /> </form> </div> <script type="text/javascript">$('#searchbox').show(0);</script> </div> </div> <h3>Last update:</h3> <p class="topless">Jan 06, 2019</p> </div> </div> <div id="ft"> <div class="nav"> <a href="../../../index.html" title="Module code" accesskey="U">up</a></div> </div> </div> <div class="clearer"></div> </div> </body> </html>