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examples.dynamic_dict.dynamic_dict
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SQLAlchemy 0.9 Documentation
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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.dynamic_dict.dynamic_dict</h1><div class="highlight"><pre>
<span class="k">class</span> <span class="nc">ProxyDict</span><span class="p">(</span><span class="nb">object</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">parent</span><span class="p">,</span> <span class="n">collection_name</span><span class="p">,</span> <span class="n">childclass</span><span class="p">,</span> <span class="n">keyname</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">parent</span> <span class="o">=</span> <span class="n">parent</span>
<span class="bp">self</span><span class="o">.</span><span class="n">collection_name</span> <span class="o">=</span> <span class="n">collection_name</span>
<span class="bp">self</span><span class="o">.</span><span class="n">childclass</span> <span class="o">=</span> <span class="n">childclass</span>
<span class="bp">self</span><span class="o">.</span><span class="n">keyname</span> <span class="o">=</span> <span class="n">keyname</span>
<span class="nd">@property</span>
<span class="k">def</span> <span class="nf">collection</span><span class="p">(</span><span class="bp">self</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">parent</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">collection_name</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">keys</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="n">descriptor</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">childclass</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">keyname</span><span class="p">)</span>
<span class="k">return</span> <span class="p">[</span><span class="n">x</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="k">for</span> <span class="n">x</span> <span class="ow">in</span> <span class="bp">self</span><span class="o">.</span><span class="n">collection</span><span class="o">.</span><span class="n">values</span><span class="p">(</span><span class="n">descriptor</span><span class="p">)]</span>
<span class="k">def</span> <span class="nf">__getitem__</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">x</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">collection</span><span class="o">.</span><span class="n">filter_by</span><span class="p">(</span><span class="o">**</span><span class="p">{</span><span class="bp">self</span><span class="o">.</span><span class="n">keyname</span><span class="p">:</span><span class="n">key</span><span class="p">})</span><span class="o">.</span><span class="n">first</span><span class="p">()</span>
<span class="k">if</span> <span class="n">x</span><span class="p">:</span>
<span class="k">return</span> <span class="n">x</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">KeyError</span><span class="p">(</span><span class="n">key</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">__setitem__</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">try</span><span class="p">:</span>
<span class="n">existing</span> <span class="o">=</span> <span class="bp">self</span><span class="p">[</span><span class="n">key</span><span class="p">]</span>
<span class="bp">self</span><span class="o">.</span><span class="n">collection</span><span class="o">.</span><span class="n">remove</span><span class="p">(</span><span class="n">existing</span><span class="p">)</span>
<span class="k">except</span> <span class="ne">KeyError</span><span class="p">:</span>
<span class="k">pass</span>
<span class="bp">self</span><span class="o">.</span><span class="n">collection</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">value</span><span class="p">)</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</span> <span class="kn">import</span> <span class="n">create_engine</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">String</span><span class="p">,</span> <span class="n">ForeignKey</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="kn">import</span> <span class="n">sessionmaker</span><span class="p">,</span> <span class="n">relationship</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">declarative_base</span><span class="p">(</span><span class="n">engine</span><span class="p">)</span>
<span class="k">class</span> <span class="nc">Parent</span><span class="p">(</span><span class="n">Base</span><span class="p">):</span>
<span class="n">__tablename__</span> <span class="o">=</span> <span class="s">'parent'</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">String</span><span class="p">(</span><span class="mi">50</span><span class="p">))</span>
<span class="n">_collection</span> <span class="o">=</span> <span class="n">relationship</span><span class="p">(</span><span class="s">"Child"</span><span class="p">,</span> <span class="n">lazy</span><span class="o">=</span><span class="s">"dynamic"</span><span class="p">,</span>
<span class="n">cascade</span><span class="o">=</span><span class="s">"all, delete-orphan"</span><span class="p">)</span>
<span class="nd">@property</span>
<span class="k">def</span> <span class="nf">child_map</span><span class="p">(</span><span class="bp">self</span><span class="p">):</span>
<span class="k">return</span> <span class="n">ProxyDict</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="s">'_collection'</span><span class="p">,</span> <span class="n">Child</span><span class="p">,</span> <span class="s">'key'</span><span class="p">)</span>
<span class="k">class</span> <span class="nc">Child</span><span class="p">(</span><span class="n">Base</span><span class="p">):</span>
<span class="n">__tablename__</span> <span class="o">=</span> <span class="s">'child'</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">key</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">String</span><span class="p">(</span><span class="mi">50</span><span class="p">))</span>
<span class="n">parent_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">ForeignKey</span><span class="p">(</span><span class="s">'parent.id'</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">"Child(key=</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">key</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">sess</span> <span class="o">=</span> <span class="n">sessionmaker</span><span class="p">()()</span>
<span class="n">p1</span> <span class="o">=</span> <span class="n">Parent</span><span class="p">(</span><span class="n">name</span><span class="o">=</span><span class="s">'p1'</span><span class="p">)</span>
<span class="n">sess</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">p1</span><span class="p">)</span>
<span class="k">print</span><span class="p">(</span><span class="s">"</span><span class="se">\n</span><span class="s">---------begin setting nodes, autoflush occurs</span><span class="se">\n</span><span class="s">"</span><span class="p">)</span>
<span class="n">p1</span><span class="o">.</span><span class="n">child_map</span><span class="p">[</span><span class="s">'k1'</span><span class="p">]</span> <span class="o">=</span> <span class="n">Child</span><span class="p">(</span><span class="n">key</span><span class="o">=</span><span class="s">'k1'</span><span class="p">)</span>
<span class="n">p1</span><span class="o">.</span><span class="n">child_map</span><span class="p">[</span><span class="s">'k2'</span><span class="p">]</span> <span class="o">=</span> <span class="n">Child</span><span class="p">(</span><span class="n">key</span><span class="o">=</span><span class="s">'k2'</span><span class="p">)</span>
<span class="c"># this will autoflush the current map.</span>
<span class="c"># ['k1', 'k2']</span>
<span class="k">print</span><span class="p">(</span><span class="s">"</span><span class="se">\n</span><span class="s">---------print keys - flushes first</span><span class="se">\n</span><span class="s">"</span><span class="p">)</span>
<span class="k">print</span><span class="p">(</span><span class="nb">list</span><span class="p">(</span><span class="n">p1</span><span class="o">.</span><span class="n">child_map</span><span class="o">.</span><span class="n">keys</span><span class="p">()))</span>
<span class="c"># k1</span>
<span class="k">print</span><span class="p">(</span><span class="s">"</span><span class="se">\n</span><span class="s">---------print 'k1' node</span><span class="se">\n</span><span class="s">"</span><span class="p">)</span>
<span class="k">print</span><span class="p">(</span><span class="n">p1</span><span class="o">.</span><span class="n">child_map</span><span class="p">[</span><span class="s">'k1'</span><span class="p">])</span>
<span class="k">print</span><span class="p">(</span><span class="s">"</span><span class="se">\n</span><span class="s">---------update 'k2' node - must find existing, and replace</span><span class="se">\n</span><span class="s">"</span><span class="p">)</span>
<span class="n">p1</span><span class="o">.</span><span class="n">child_map</span><span class="p">[</span><span class="s">'k2'</span><span class="p">]</span> <span class="o">=</span> <span class="n">Child</span><span class="p">(</span><span class="n">key</span><span class="o">=</span><span class="s">'k2'</span><span class="p">)</span>
<span class="k">print</span><span class="p">(</span><span class="s">"</span><span class="se">\n</span><span class="s">---------print 'k2' key - flushes first</span><span class="se">\n</span><span class="s">"</span><span class="p">)</span>
<span class="c"># k2</span>
<span class="k">print</span><span class="p">(</span><span class="n">p1</span><span class="o">.</span><span class="n">child_map</span><span class="p">[</span><span class="s">'k2'</span><span class="p">])</span>
<span class="k">print</span><span class="p">(</span><span class="s">"</span><span class="se">\n</span><span class="s">---------print all child nodes</span><span class="se">\n</span><span class="s">"</span><span class="p">)</span>
<span class="c"># [k1, k2b]</span>
<span class="k">print</span><span class="p">(</span><span class="n">sess</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Child</span><span class="p">)</span><span class="o">.</span><span class="n">all</span><span class="p">())</span></pre></div>
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