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Release: <span class="version-num">0.9.8</span> | Release Date: October 13, 2014
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<h1>SQLAlchemy 0.9 Documentation</h1>
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<h1>Source code for examples.vertical.dictlike-polymorphic</h1><div class="highlight"><pre>
<span class="sd">"""Mapping a polymorphic-valued vertical table as a dictionary.</span>
<span class="sd">Builds upon the dictlike.py example to also add differently typed</span>
<span class="sd">columns to the "fact" table, e.g.::</span>
<span class="sd"> Table('properties', metadata</span>
<span class="sd"> Column('owner_id', Integer, ForeignKey('owner.id'),</span>
<span class="sd"> primary_key=True),</span>
<span class="sd"> Column('key', UnicodeText),</span>
<span class="sd"> Column('type', Unicode(16)),</span>
<span class="sd"> Column('int_value', Integer),</span>
<span class="sd"> Column('char_value', UnicodeText),</span>
<span class="sd"> Column('bool_value', Boolean),</span>
<span class="sd"> Column('decimal_value', Numeric(10,2)))</span>
<span class="sd">For any given properties row, the value of the 'type' column will point to the</span>
<span class="sd">'_value' column active for that row.</span>
<span class="sd">This example approach uses exactly the same dict mapping approach as the</span>
<span class="sd">'dictlike' example. It only differs in the mapping for vertical rows. Here,</span>
<span class="sd">we'll use a @hybrid_property to build a smart '.value' attribute that wraps up</span>
<span class="sd">reading and writing those various '_value' columns and keeps the '.type' up to</span>
<span class="sd">date.</span>
<span class="sd">"""</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm.interfaces</span> <span class="kn">import</span> <span class="n">PropComparator</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.ext.hybrid</span> <span class="kn">import</span> <span class="n">hybrid_property</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="kn">import</span> <span class="n">event</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="kn">import</span> <span class="n">literal_column</span>
<span class="kn">from</span> <span class="nn">.dictlike</span> <span class="kn">import</span> <span class="n">ProxiedDictMixin</span>
<span class="k">class</span> <span class="nc">PolymorphicVerticalProperty</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="sd">"""A key/value pair with polymorphic value storage.</span>
<span class="sd"> The class which is mapped should indicate typing information</span>
<span class="sd"> within the "info" dictionary of mapped Column objects; see</span>
<span class="sd"> the AnimalFact mapping below for an example.</span>
<span class="sd"> """</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">key</span><span class="p">,</span> <span class="n">value</span><span class="o">=</span><span class="bp">None</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">key</span> <span class="o">=</span> <span class="n">key</span>
<span class="bp">self</span><span class="o">.</span><span class="n">value</span> <span class="o">=</span> <span class="n">value</span>
<span class="nd">@hybrid_property</span>
<span class="k">def</span> <span class="nf">value</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">fieldname</span><span class="p">,</span> <span class="n">discriminator</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">type_map</span><span class="p">[</span><span class="bp">self</span><span class="o">.</span><span class="n">type</span><span class="p">]</span>
<span class="k">if</span> <span class="n">fieldname</span> <span class="ow">is</span> <span class="bp">None</span><span class="p">:</span>
<span class="k">return</span> <span class="bp">None</span>
<span class="k">else</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="p">,</span> <span class="n">fieldname</span><span class="p">)</span>
<span class="nd">@value.setter</span>
<span class="k">def</span> <span class="nf">value</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">value</span><span class="p">):</span>
<span class="n">py_type</span> <span class="o">=</span> <span class="nb">type</span><span class="p">(</span><span class="n">value</span><span class="p">)</span>
<span class="n">fieldname</span><span class="p">,</span> <span class="n">discriminator</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">type_map</span><span class="p">[</span><span class="n">py_type</span><span class="p">]</span>
<span class="bp">self</span><span class="o">.</span><span class="n">type</span> <span class="o">=</span> <span class="n">discriminator</span>
<span class="k">if</span> <span class="n">fieldname</span> <span class="ow">is</span> <span class="ow">not</span> <span class="bp">None</span><span class="p">:</span>
<span class="nb">setattr</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">fieldname</span><span class="p">,</span> <span class="n">value</span><span class="p">)</span>
<span class="nd">@value.deleter</span>
<span class="k">def</span> <span class="nf">value</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">_set_value</span><span class="p">(</span><span class="bp">None</span><span class="p">)</span>
<span class="nd">@value.comparator</span>
<span class="k">class</span> <span class="nc">value</span><span class="p">(</span><span class="n">PropComparator</span><span class="p">):</span>
<span class="sd">"""A comparator for .value, builds a polymorphic comparison via CASE.</span>
<span class="sd"> """</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">cls</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">cls</span> <span class="o">=</span> <span class="n">cls</span>
<span class="k">def</span> <span class="nf">_case</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">pairs</span> <span class="o">=</span> <span class="nb">set</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">cls</span><span class="o">.</span><span class="n">type_map</span><span class="o">.</span><span class="n">values</span><span class="p">())</span>
<span class="n">whens</span> <span class="o">=</span> <span class="p">[</span>
<span class="p">(</span>
<span class="n">literal_column</span><span class="p">(</span><span class="s">"'</span><span class="si">%s</span><span class="s">'"</span> <span class="o">%</span> <span class="n">discriminator</span><span class="p">),</span>
<span class="n">cast</span><span class="p">(</span><span class="nb">getattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">cls</span><span class="p">,</span> <span class="n">attribute</span><span class="p">),</span> <span class="n">String</span><span class="p">)</span>
<span class="p">)</span> <span class="k">for</span> <span class="n">attribute</span><span class="p">,</span> <span class="n">discriminator</span> <span class="ow">in</span> <span class="n">pairs</span>
<span class="k">if</span> <span class="n">attribute</span> <span class="ow">is</span> <span class="ow">not</span> <span class="bp">None</span>
<span class="p">]</span>
<span class="k">return</span> <span class="n">case</span><span class="p">(</span><span class="n">whens</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">cls</span><span class="o">.</span><span class="n">type</span><span class="p">,</span> <span class="n">null</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="bp">self</span><span class="o">.</span><span class="n">_case</span><span class="p">()</span> <span class="o">==</span> <span class="n">cast</span><span class="p">(</span><span class="n">other</span><span class="p">,</span> <span class="n">String</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="bp">self</span><span class="o">.</span><span class="n">_case</span><span class="p">()</span> <span class="o">!=</span> <span class="n">cast</span><span class="p">(</span><span class="n">other</span><span class="p">,</span> <span class="n">String</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">__repr__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s">'<</span><span class="si">%s</span><span class="s"> </span><span class="si">%r</span><span class="s">=</span><span class="si">%r</span><span class="s">>'</span> <span class="o">%</span> <span class="p">(</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="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">key</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">value</span><span class="p">)</span>
<span class="nd">@event.listens_for</span><span class="p">(</span><span class="n">PolymorphicVerticalProperty</span><span class="p">,</span> <span class="s">"mapper_configured"</span><span class="p">,</span> <span class="n">propagate</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">on_new_class</span><span class="p">(</span><span class="n">mapper</span><span class="p">,</span> <span class="n">cls_</span><span class="p">):</span>
<span class="sd">"""Look for Column objects with type info in them, and work up</span>
<span class="sd"> a lookup table."""</span>
<span class="n">info_dict</span> <span class="o">=</span> <span class="p">{}</span>
<span class="n">info_dict</span><span class="p">[</span><span class="nb">type</span><span class="p">(</span><span class="bp">None</span><span class="p">)]</span> <span class="o">=</span> <span class="p">(</span><span class="bp">None</span><span class="p">,</span> <span class="s">'none'</span><span class="p">)</span>
<span class="n">info_dict</span><span class="p">[</span><span class="s">'none'</span><span class="p">]</span> <span class="o">=</span> <span class="p">(</span><span class="bp">None</span><span class="p">,</span> <span class="s">'none'</span><span class="p">)</span>
<span class="k">for</span> <span class="n">k</span> <span class="ow">in</span> <span class="n">mapper</span><span class="o">.</span><span class="n">c</span><span class="o">.</span><span class="n">keys</span><span class="p">():</span>
<span class="n">col</span> <span class="o">=</span> <span class="n">mapper</span><span class="o">.</span><span class="n">c</span><span class="p">[</span><span class="n">k</span><span class="p">]</span>
<span class="k">if</span> <span class="s">'type'</span> <span class="ow">in</span> <span class="n">col</span><span class="o">.</span><span class="n">info</span><span class="p">:</span>
<span class="n">python_type</span><span class="p">,</span> <span class="n">discriminator</span> <span class="o">=</span> <span class="n">col</span><span class="o">.</span><span class="n">info</span><span class="p">[</span><span class="s">'type'</span><span class="p">]</span>
<span class="n">info_dict</span><span class="p">[</span><span class="n">python_type</span><span class="p">]</span> <span class="o">=</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">discriminator</span><span class="p">)</span>
<span class="n">info_dict</span><span class="p">[</span><span class="n">discriminator</span><span class="p">]</span> <span class="o">=</span> <span class="p">(</span><span class="n">k</span><span class="p">,</span> <span class="n">discriminator</span><span class="p">)</span>
<span class="n">cls_</span><span class="o">.</span><span class="n">type_map</span> <span class="o">=</span> <span class="n">info_dict</span>
<span class="k">if</span> <span class="n">__name__</span> <span class="o">==</span> <span class="s">'__main__'</span><span class="p">:</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="kn">import</span> <span class="p">(</span><span class="n">Column</span><span class="p">,</span> <span class="n">Integer</span><span class="p">,</span> <span class="n">Unicode</span><span class="p">,</span>
<span class="n">ForeignKey</span><span class="p">,</span> <span class="n">UnicodeText</span><span class="p">,</span> <span class="n">and_</span><span class="p">,</span> <span class="n">or_</span><span class="p">,</span> <span class="n">String</span><span class="p">,</span> <span class="n">Boolean</span><span class="p">,</span> <span class="n">cast</span><span class="p">,</span>
<span class="n">null</span><span class="p">,</span> <span class="n">case</span><span class="p">,</span> <span class="n">create_engine</span><span class="p">)</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="kn">import</span> <span class="n">relationship</span><span class="p">,</span> <span class="n">Session</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm.collections</span> <span class="kn">import</span> <span class="n">attribute_mapped_collection</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.ext.declarative</span> <span class="kn">import</span> <span class="n">declarative_base</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.ext.associationproxy</span> <span class="kn">import</span> <span class="n">association_proxy</span>
<span class="n">Base</span> <span class="o">=</span> <span class="n">declarative_base</span><span class="p">()</span>
<span class="k">class</span> <span class="nc">AnimalFact</span><span class="p">(</span><span class="n">PolymorphicVerticalProperty</span><span class="p">,</span> <span class="n">Base</span><span class="p">):</span>
<span class="sd">"""A fact about an animal."""</span>
<span class="n">__tablename__</span> <span class="o">=</span> <span class="s">'animal_fact'</span>
<span class="n">animal_id</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">ForeignKey</span><span class="p">(</span><span class="s">'animal.id'</span><span class="p">),</span> <span class="n">primary_key</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="n">key</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">Unicode</span><span class="p">(</span><span class="mi">64</span><span class="p">),</span> <span class="n">primary_key</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="nb">type</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">Unicode</span><span class="p">(</span><span class="mi">16</span><span class="p">))</span>
<span class="c"># add information about storage for different types</span>
<span class="c"># in the info dictionary of Columns</span>
<span class="n">int_value</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">Integer</span><span class="p">,</span> <span class="n">info</span><span class="o">=</span><span class="p">{</span><span class="s">'type'</span><span class="p">:</span> <span class="p">(</span><span class="nb">int</span><span class="p">,</span> <span class="s">'integer'</span><span class="p">)})</span>
<span class="n">char_value</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">UnicodeText</span><span class="p">,</span> <span class="n">info</span><span class="o">=</span><span class="p">{</span><span class="s">'type'</span><span class="p">:</span> <span class="p">(</span><span class="nb">str</span><span class="p">,</span> <span class="s">'string'</span><span class="p">)})</span>
<span class="n">boolean_value</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">Boolean</span><span class="p">,</span> <span class="n">info</span><span class="o">=</span><span class="p">{</span><span class="s">'type'</span><span class="p">:</span> <span class="p">(</span><span class="nb">bool</span><span class="p">,</span> <span class="s">'boolean'</span><span class="p">)})</span>
<span class="k">class</span> <span class="nc">Animal</span><span class="p">(</span><span class="n">ProxiedDictMixin</span><span class="o">.</span><span class="n">_base_class</span><span class="p">(</span><span class="n">Base</span><span class="p">)):</span>
<span class="sd">"""an Animal"""</span>
<span class="n">__tablename__</span> <span class="o">=</span> <span class="s">'animal'</span>
<span class="nb">id</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">Integer</span><span class="p">,</span> <span class="n">primary_key</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="n">name</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">Unicode</span><span class="p">(</span><span class="mi">100</span><span class="p">))</span>
<span class="n">facts</span> <span class="o">=</span> <span class="n">relationship</span><span class="p">(</span><span class="s">"AnimalFact"</span><span class="p">,</span>
<span class="n">collection_class</span><span class="o">=</span><span class="n">attribute_mapped_collection</span><span class="p">(</span><span class="s">'key'</span><span class="p">))</span>
<span class="n">_proxied</span> <span class="o">=</span> <span class="n">association_proxy</span><span class="p">(</span><span class="s">"facts"</span><span class="p">,</span> <span class="s">"value"</span><span class="p">,</span>
<span class="n">creator</span><span class="o">=</span>
<span class="k">lambda</span> <span class="n">key</span><span class="p">,</span> <span class="n">value</span><span class="p">:</span> <span class="n">AnimalFact</span><span class="p">(</span><span class="n">key</span><span class="o">=</span><span class="n">key</span><span class="p">,</span> <span class="n">value</span><span class="o">=</span><span class="n">value</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">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="k">def</span> <span class="nf">__repr__</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="s">"Animal(</span><span class="si">%r</span><span class="s">)"</span> <span class="o">%</span> <span class="bp">self</span><span class="o">.</span><span class="n">name</span>
<span class="nd">@classmethod</span>
<span class="k">def</span> <span class="nf">with_characteristic</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">key</span><span class="p">,</span> <span class="n">value</span><span class="p">):</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">facts</span><span class="o">.</span><span class="n">any</span><span class="p">(</span><span class="n">key</span><span class="o">=</span><span class="n">key</span><span class="p">,</span> <span class="n">value</span><span class="o">=</span><span class="n">value</span><span class="p">)</span>
<span class="n">engine</span> <span class="o">=</span> <span class="n">create_engine</span><span class="p">(</span><span class="s">'sqlite://'</span><span class="p">,</span> <span class="n">echo</span><span class="o">=</span><span class="bp">True</span><span class="p">)</span>
<span class="n">Base</span><span class="o">.</span><span class="n">metadata</span><span class="o">.</span><span class="n">create_all</span><span class="p">(</span><span class="n">engine</span><span class="p">)</span>
<span class="n">session</span> <span class="o">=</span> <span class="n">Session</span><span class="p">(</span><span class="n">engine</span><span class="p">)</span>
<span class="n">stoat</span> <span class="o">=</span> <span class="n">Animal</span><span class="p">(</span><span class="s">'stoat'</span><span class="p">)</span>
<span class="n">stoat</span><span class="p">[</span><span class="s">'color'</span><span class="p">]</span> <span class="o">=</span> <span class="s">'red'</span>
<span class="n">stoat</span><span class="p">[</span><span class="s">'cuteness'</span><span class="p">]</span> <span class="o">=</span> <span class="mi">7</span>
<span class="n">stoat</span><span class="p">[</span><span class="s">'weasel-like'</span><span class="p">]</span> <span class="o">=</span> <span class="bp">True</span>
<span class="n">session</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">stoat</span><span class="p">)</span>
<span class="n">session</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="n">critter</span> <span class="o">=</span> <span class="n">session</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Animal</span><span class="p">)</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span><span class="n">Animal</span><span class="o">.</span><span class="n">name</span> <span class="o">==</span> <span class="s">'stoat'</span><span class="p">)</span><span class="o">.</span><span class="n">one</span><span class="p">()</span>
<span class="k">print</span><span class="p">(</span><span class="n">critter</span><span class="p">[</span><span class="s">'color'</span><span class="p">])</span>
<span class="k">print</span><span class="p">(</span><span class="n">critter</span><span class="p">[</span><span class="s">'cuteness'</span><span class="p">])</span>
<span class="k">print</span><span class="p">(</span><span class="s">"changing cuteness value and type:"</span><span class="p">)</span>
<span class="n">critter</span><span class="p">[</span><span class="s">'cuteness'</span><span class="p">]</span> <span class="o">=</span> <span class="s">'very cute'</span>
<span class="n">session</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="n">marten</span> <span class="o">=</span> <span class="n">Animal</span><span class="p">(</span><span class="s">'marten'</span><span class="p">)</span>
<span class="n">marten</span><span class="p">[</span><span class="s">'cuteness'</span><span class="p">]</span> <span class="o">=</span> <span class="mi">5</span>
<span class="n">marten</span><span class="p">[</span><span class="s">'weasel-like'</span><span class="p">]</span> <span class="o">=</span> <span class="bp">True</span>
<span class="n">marten</span><span class="p">[</span><span class="s">'poisonous'</span><span class="p">]</span> <span class="o">=</span> <span class="bp">False</span>
<span class="n">session</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">marten</span><span class="p">)</span>
<span class="n">shrew</span> <span class="o">=</span> <span class="n">Animal</span><span class="p">(</span><span class="s">'shrew'</span><span class="p">)</span>
<span class="n">shrew</span><span class="p">[</span><span class="s">'cuteness'</span><span class="p">]</span> <span class="o">=</span> <span class="mi">5</span>
<span class="n">shrew</span><span class="p">[</span><span class="s">'weasel-like'</span><span class="p">]</span> <span class="o">=</span> <span class="bp">False</span>
<span class="n">shrew</span><span class="p">[</span><span class="s">'poisonous'</span><span class="p">]</span> <span class="o">=</span> <span class="bp">True</span>
<span class="n">session</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">shrew</span><span class="p">)</span>
<span class="n">session</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="n">q</span> <span class="o">=</span> <span class="p">(</span><span class="n">session</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Animal</span><span class="p">)</span><span class="o">.</span>
<span class="nb">filter</span><span class="p">(</span><span class="n">Animal</span><span class="o">.</span><span class="n">facts</span><span class="o">.</span><span class="n">any</span><span class="p">(</span>
<span class="n">and_</span><span class="p">(</span><span class="n">AnimalFact</span><span class="o">.</span><span class="n">key</span> <span class="o">==</span> <span class="s">'weasel-like'</span><span class="p">,</span>
<span class="n">AnimalFact</span><span class="o">.</span><span class="n">value</span> <span class="o">==</span> <span class="bp">True</span><span class="p">))))</span>
<span class="k">print</span><span class="p">(</span><span class="s">'weasel-like animals'</span><span class="p">,</span> <span class="n">q</span><span class="o">.</span><span class="n">all</span><span class="p">())</span>
<span class="n">q</span> <span class="o">=</span> <span class="p">(</span><span class="n">session</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Animal</span><span class="p">)</span><span class="o">.</span>
<span class="nb">filter</span><span class="p">(</span><span class="n">Animal</span><span class="o">.</span><span class="n">with_characteristic</span><span class="p">(</span><span class="s">'weasel-like'</span><span class="p">,</span> <span class="bp">True</span><span class="p">)))</span>
<span class="k">print</span><span class="p">(</span><span class="s">'weasel-like animals again'</span><span class="p">,</span> <span class="n">q</span><span class="o">.</span><span class="n">all</span><span class="p">())</span>
<span class="n">q</span> <span class="o">=</span> <span class="p">(</span><span class="n">session</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Animal</span><span class="p">)</span><span class="o">.</span>
<span class="nb">filter</span><span class="p">(</span><span class="n">Animal</span><span class="o">.</span><span class="n">with_characteristic</span><span class="p">(</span><span class="s">'poisonous'</span><span class="p">,</span> <span class="bp">False</span><span class="p">)))</span>
<span class="k">print</span><span class="p">(</span><span class="s">'animals with poisonous=False'</span><span class="p">,</span> <span class="n">q</span><span class="o">.</span><span class="n">all</span><span class="p">())</span>
<span class="n">q</span> <span class="o">=</span> <span class="p">(</span><span class="n">session</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Animal</span><span class="p">)</span><span class="o">.</span>
<span class="nb">filter</span><span class="p">(</span><span class="n">or_</span><span class="p">(</span>
<span class="n">Animal</span><span class="o">.</span><span class="n">with_characteristic</span><span class="p">(</span><span class="s">'poisonous'</span><span class="p">,</span> <span class="bp">False</span><span class="p">),</span>
<span class="o">~</span><span class="n">Animal</span><span class="o">.</span><span class="n">facts</span><span class="o">.</span><span class="n">any</span><span class="p">(</span><span class="n">AnimalFact</span><span class="o">.</span><span class="n">key</span> <span class="o">==</span> <span class="s">'poisonous'</span><span class="p">)</span>
<span class="p">)</span>
<span class="p">)</span>
<span class="p">)</span>
<span class="k">print</span><span class="p">(</span><span class="s">'non-poisonous animals'</span><span class="p">,</span> <span class="n">q</span><span class="o">.</span><span class="n">all</span><span class="p">())</span>
<span class="n">q</span> <span class="o">=</span> <span class="p">(</span><span class="n">session</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Animal</span><span class="p">)</span><span class="o">.</span>
<span class="nb">filter</span><span class="p">(</span><span class="n">Animal</span><span class="o">.</span><span class="n">facts</span><span class="o">.</span><span class="n">any</span><span class="p">(</span><span class="n">AnimalFact</span><span class="o">.</span><span class="n">value</span> <span class="o">==</span> <span class="mi">5</span><span class="p">)))</span>
<span class="k">print</span><span class="p">(</span><span class="s">'any animal with a .value of 5'</span><span class="p">,</span> <span class="n">q</span><span class="o">.</span><span class="n">all</span><span class="p">())</span></pre></div>
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