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Release: <span class="version-num">1.2.19</span>
| Release Date: April 15, 2019
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<h1>SQLAlchemy 1.2 Documentation</h1>
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<h1>Source code for examples.versioned_rows.versioned_update_old_row</h1><div class="highlight"><pre>
<span></span><span class="sd">"""Illustrates the same UPDATE into INSERT technique of ``versioned_rows.py``,</span>
<span class="sd">but also emits an UPDATE on the **old** row to affect a change in timestamp.</span>
<span class="sd">Also includes a :meth:`.QueryEvents.before_compile` hook to limit queries</span>
<span class="sd">to only the most recent version.</span>
<span class="sd">"""</span>
<span class="kn">import</span> <span class="nn">datetime</span>
<span class="kn">import</span> <span class="nn">time</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">Column</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">create_engine</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">DateTime</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">event</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">inspect</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">Integer</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">literal</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="k">import</span> <span class="n">String</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.ext.declarative</span> <span class="k">import</span> <span class="n">declarative_base</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="k">import</span> <span class="n">attributes</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="k">import</span> <span class="n">backref</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="k">import</span> <span class="n">make_transient</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="k">import</span> <span class="n">make_transient_to_detached</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="k">import</span> <span class="n">Query</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="k">import</span> <span class="n">relationship</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="k">import</span> <span class="n">Session</span>
<span class="n">Base</span> <span class="o">=</span> <span class="n">declarative_base</span><span class="p">()</span>
<span class="c1"># this will be the current time as the test runs</span>
<span class="n">now</span> <span class="o">=</span> <span class="kc">None</span>
<span class="c1"># in practice this would be a real "now" function</span>
<span class="k">def</span> <span class="nf">current_time</span><span class="p">():</span>
<span class="k">return</span> <span class="n">now</span>
<span class="k">class</span> <span class="nc">VersionedStartEnd</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="o">**</span><span class="n">kw</span><span class="p">):</span>
<span class="c1"># reduce some verbosity when we make a new object</span>
<span class="n">kw</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="s2">"start"</span><span class="p">,</span> <span class="n">current_time</span><span class="p">()</span> <span class="o">-</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">))</span>
<span class="n">kw</span><span class="o">.</span><span class="n">setdefault</span><span class="p">(</span><span class="s2">"end"</span><span class="p">,</span> <span class="n">current_time</span><span class="p">()</span> <span class="o">+</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">))</span>
<span class="nb">super</span><span class="p">(</span><span class="n">VersionedStartEnd</span><span class="p">,</span> <span class="bp">self</span><span class="p">)</span><span class="o">.</span><span class="fm">__init__</span><span class="p">(</span><span class="o">**</span><span class="n">kw</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">new_version</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">session</span><span class="p">):</span>
<span class="c1"># our current identity key, which will be used on the "old"</span>
<span class="c1"># version of us to emit an UPDATE. this is just for assertion purposes</span>
<span class="n">old_identity_key</span> <span class="o">=</span> <span class="n">inspect</span><span class="p">(</span><span class="bp">self</span><span class="p">)</span><span class="o">.</span><span class="n">key</span>
<span class="c1"># make sure self.start / self.end are not expired</span>
<span class="bp">self</span><span class="o">.</span><span class="n">id</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">start</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">end</span>
<span class="c1"># turn us into an INSERT</span>
<span class="n">make_transient</span><span class="p">(</span><span class="bp">self</span><span class="p">)</span>
<span class="c1"># make the "old" version of us, which we will turn into an</span>
<span class="c1"># UPDATE</span>
<span class="n">old_copy_of_us</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="vm">__class__</span><span class="p">(</span>
<span class="nb">id</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">id</span><span class="p">,</span> <span class="n">start</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">start</span><span class="p">,</span> <span class="n">end</span><span class="o">=</span><span class="bp">self</span><span class="o">.</span><span class="n">end</span>
<span class="p">)</span>
<span class="c1"># turn old_copy_of_us into an UPDATE</span>
<span class="n">make_transient_to_detached</span><span class="p">(</span><span class="n">old_copy_of_us</span><span class="p">)</span>
<span class="c1"># the "old" object has our old identity key (that we no longer have)</span>
<span class="k">assert</span> <span class="n">inspect</span><span class="p">(</span><span class="n">old_copy_of_us</span><span class="p">)</span><span class="o">.</span><span class="n">key</span> <span class="o">==</span> <span class="n">old_identity_key</span>
<span class="c1"># now put it back in the session</span>
<span class="n">session</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">old_copy_of_us</span><span class="p">)</span>
<span class="c1"># now update the 'end' - SQLAlchemy sees this as a PK switch</span>
<span class="n">old_copy_of_us</span><span class="o">.</span><span class="n">end</span> <span class="o">=</span> <span class="n">current_time</span><span class="p">()</span>
<span class="c1"># fun fact! the new_version() routine is *not* called for</span>
<span class="c1"># old_copy_of_us! because we are already in the before_flush() hook!</span>
<span class="c1"># this surprised even me. I was thinking we had to guard against</span>
<span class="c1"># it. Still might be a good idea to do so.</span>
<span class="bp">self</span><span class="o">.</span><span class="n">start</span> <span class="o">=</span> <span class="n">current_time</span><span class="p">()</span>
<span class="bp">self</span><span class="o">.</span><span class="n">end</span> <span class="o">=</span> <span class="n">current_time</span><span class="p">()</span> <span class="o">+</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">2</span><span class="p">)</span>
<span class="nd">@event</span><span class="o">.</span><span class="n">listens_for</span><span class="p">(</span><span class="n">Session</span><span class="p">,</span> <span class="s2">"before_flush"</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">before_flush</span><span class="p">(</span><span class="n">session</span><span class="p">,</span> <span class="n">flush_context</span><span class="p">,</span> <span class="n">instances</span><span class="p">):</span>
<span class="k">for</span> <span class="n">instance</span> <span class="ow">in</span> <span class="n">session</span><span class="o">.</span><span class="n">dirty</span><span class="p">:</span>
<span class="k">if</span> <span class="ow">not</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">instance</span><span class="p">,</span> <span class="n">VersionedStartEnd</span><span class="p">):</span>
<span class="k">continue</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">session</span><span class="o">.</span><span class="n">is_modified</span><span class="p">(</span><span class="n">instance</span><span class="p">,</span> <span class="n">passive</span><span class="o">=</span><span class="kc">True</span><span class="p">):</span>
<span class="k">continue</span>
<span class="k">if</span> <span class="ow">not</span> <span class="n">attributes</span><span class="o">.</span><span class="n">instance_state</span><span class="p">(</span><span class="n">instance</span><span class="p">)</span><span class="o">.</span><span class="n">has_identity</span><span class="p">:</span>
<span class="k">continue</span>
<span class="c1"># make it transient</span>
<span class="n">instance</span><span class="o">.</span><span class="n">new_version</span><span class="p">(</span><span class="n">session</span><span class="p">)</span>
<span class="c1"># re-add</span>
<span class="n">session</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">instance</span><span class="p">)</span>
<span class="nd">@event</span><span class="o">.</span><span class="n">listens_for</span><span class="p">(</span><span class="n">Query</span><span class="p">,</span> <span class="s2">"before_compile"</span><span class="p">,</span> <span class="n">retval</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="k">def</span> <span class="nf">before_compile</span><span class="p">(</span><span class="n">query</span><span class="p">):</span>
<span class="sd">"""ensure all queries for VersionedStartEnd include criteria """</span>
<span class="k">for</span> <span class="n">ent</span> <span class="ow">in</span> <span class="n">query</span><span class="o">.</span><span class="n">column_descriptions</span><span class="p">:</span>
<span class="n">entity</span> <span class="o">=</span> <span class="n">ent</span><span class="p">[</span><span class="s2">"entity"</span><span class="p">]</span>
<span class="k">if</span> <span class="n">entity</span> <span class="ow">is</span> <span class="kc">None</span><span class="p">:</span>
<span class="k">continue</span>
<span class="n">insp</span> <span class="o">=</span> <span class="n">inspect</span><span class="p">(</span><span class="n">ent</span><span class="p">[</span><span class="s2">"entity"</span><span class="p">])</span>
<span class="n">mapper</span> <span class="o">=</span> <span class="nb">getattr</span><span class="p">(</span><span class="n">insp</span><span class="p">,</span> <span class="s2">"mapper"</span><span class="p">,</span> <span class="kc">None</span><span class="p">)</span>
<span class="k">if</span> <span class="n">mapper</span> <span class="ow">and</span> <span class="nb">issubclass</span><span class="p">(</span><span class="n">mapper</span><span class="o">.</span><span class="n">class_</span><span class="p">,</span> <span class="n">VersionedStartEnd</span><span class="p">):</span>
<span class="n">query</span> <span class="o">=</span> <span class="n">query</span><span class="o">.</span><span class="n">enable_assertions</span><span class="p">(</span><span class="kc">False</span><span class="p">)</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span>
<span class="c1"># using a literal "now" because SQLite's "between"</span>
<span class="c1"># seems to be inclusive. In practice, this would be</span>
<span class="c1"># ``func.now()`` and we'd be using PostgreSQL</span>
<span class="n">literal</span><span class="p">(</span>
<span class="n">current_time</span><span class="p">()</span> <span class="o">+</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">seconds</span><span class="o">=</span><span class="mi">1</span><span class="p">)</span>
<span class="p">)</span><span class="o">.</span><span class="n">between</span><span class="p">(</span><span class="n">ent</span><span class="p">[</span><span class="s2">"entity"</span><span class="p">]</span><span class="o">.</span><span class="n">start</span><span class="p">,</span> <span class="n">ent</span><span class="p">[</span><span class="s2">"entity"</span><span class="p">]</span><span class="o">.</span><span class="n">end</span><span class="p">)</span>
<span class="p">)</span>
<span class="k">return</span> <span class="n">query</span>
<span class="k">class</span> <span class="nc">Parent</span><span class="p">(</span><span class="n">VersionedStartEnd</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="s2">"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="kc">True</span><span class="p">)</span>
<span class="n">start</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">DateTime</span><span class="p">,</span> <span class="n">primary_key</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="n">end</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">DateTime</span><span class="p">,</span> <span class="n">primary_key</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="n">data</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="n">child_n</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">child</span> <span class="o">=</span> <span class="n">relationship</span><span class="p">(</span>
<span class="s2">"Child"</span><span class="p">,</span>
<span class="n">primaryjoin</span><span class="o">=</span><span class="p">(</span><span class="s2">"Child.id == foreign(Parent.child_n)"</span><span class="p">),</span>
<span class="c1"># note the primaryjoin can also be:</span>
<span class="c1">#</span>
<span class="c1"># "and_(Child.id == foreign(Parent.child_n), "</span>
<span class="c1"># "func.now().between(Child.start, Child.end))"</span>
<span class="c1">#</span>
<span class="c1"># however the before_compile() above will take care of this for us in</span>
<span class="c1"># all cases except for joinedload. You *can* use the above primaryjoin</span>
<span class="c1"># as well, it just means the criteria will be present twice for most</span>
<span class="c1"># parent->child load operations</span>
<span class="c1">#</span>
<span class="n">uselist</span><span class="o">=</span><span class="kc">False</span><span class="p">,</span>
<span class="n">backref</span><span class="o">=</span><span class="n">backref</span><span class="p">(</span><span class="s2">"parent"</span><span class="p">,</span> <span class="n">uselist</span><span class="o">=</span><span class="kc">False</span><span class="p">),</span>
<span class="p">)</span>
<span class="k">class</span> <span class="nc">Child</span><span class="p">(</span><span class="n">VersionedStartEnd</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="s2">"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="kc">True</span><span class="p">)</span>
<span class="n">start</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">DateTime</span><span class="p">,</span> <span class="n">primary_key</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="n">end</span> <span class="o">=</span> <span class="n">Column</span><span class="p">(</span><span class="n">DateTime</span><span class="p">,</span> <span class="n">primary_key</span><span class="o">=</span><span class="kc">True</span><span class="p">)</span>
<span class="n">data</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="k">def</span> <span class="nf">new_version</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">session</span><span class="p">):</span>
<span class="c1"># expire parent's reference to us</span>
<span class="n">session</span><span class="o">.</span><span class="n">expire</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="p">[</span><span class="s2">"child"</span><span class="p">])</span>
<span class="c1"># create new version</span>
<span class="n">VersionedStartEnd</span><span class="o">.</span><span class="n">new_version</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">session</span><span class="p">)</span>
<span class="c1"># re-add ourselves to the parent</span>
<span class="bp">self</span><span class="o">.</span><span class="n">parent</span><span class="o">.</span><span class="n">child</span> <span class="o">=</span> <span class="bp">self</span>
<span class="n">times</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">def</span> <span class="nf">time_passes</span><span class="p">(</span><span class="n">s</span><span class="p">):</span>
<span class="sd">"""keep track of timestamps in terms of the database and allow time to</span>
<span class="sd"> pass between steps."""</span>
<span class="c1"># close the transaction, if any, since PG time doesn't increment in the</span>
<span class="c1"># transaction</span>
<span class="n">s</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="c1"># get "now" in terms of the DB so we can keep the ranges low and</span>
<span class="c1"># still have our assertions pass</span>
<span class="k">if</span> <span class="n">times</span><span class="p">:</span>
<span class="n">time</span><span class="o">.</span><span class="n">sleep</span><span class="p">(</span><span class="mi">1</span><span class="p">)</span>
<span class="n">times</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">datetime</span><span class="o">.</span><span class="n">datetime</span><span class="o">.</span><span class="n">now</span><span class="p">())</span>
<span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">times</span><span class="p">)</span> <span class="o">></span> <span class="mi">1</span><span class="p">:</span>
<span class="k">assert</span> <span class="n">times</span><span class="p">[</span><span class="o">-</span><span class="mi">1</span><span class="p">]</span> <span class="o">></span> <span class="n">times</span><span class="p">[</span><span class="o">-</span><span class="mi">2</span><span class="p">]</span>
<span class="k">return</span> <span class="n">times</span><span class="p">[</span><span class="o">-</span><span class="mi">1</span><span class="p">]</span>
<span class="n">e</span> <span class="o">=</span> <span class="n">create_engine</span><span class="p">(</span><span class="s2">"sqlite://"</span><span class="p">,</span> <span class="n">echo</span><span class="o">=</span><span class="s2">"debug"</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">e</span><span class="p">)</span>
<span class="n">s</span> <span class="o">=</span> <span class="n">Session</span><span class="p">(</span><span class="n">e</span><span class="p">)</span>
<span class="n">now</span> <span class="o">=</span> <span class="n">time_passes</span><span class="p">(</span><span class="n">s</span><span class="p">)</span>
<span class="n">c1</span> <span class="o">=</span> <span class="n">Child</span><span class="p">(</span><span class="nb">id</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">data</span><span class="o">=</span><span class="s2">"child 1"</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="nb">id</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">data</span><span class="o">=</span><span class="s2">"c1"</span><span class="p">,</span> <span class="n">child</span><span class="o">=</span><span class="n">c1</span><span class="p">)</span>
<span class="n">s</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="n">s</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="c1"># assert raw DB data</span>
<span class="k">assert</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Parent</span><span class="o">.</span><span class="n">__table__</span><span class="p">)</span><span class="o">.</span><span class="n">all</span><span class="p">()</span> <span class="o">==</span> <span class="p">[</span>
<span class="p">(</span>
<span class="mi">1</span><span class="p">,</span>
<span class="n">times</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">-</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">),</span>
<span class="n">times</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">+</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">),</span>
<span class="s2">"c1"</span><span class="p">,</span>
<span class="mi">1</span><span class="p">,</span>
<span class="p">)</span>
<span class="p">]</span>
<span class="k">assert</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Child</span><span class="o">.</span><span class="n">__table__</span><span class="p">)</span><span class="o">.</span><span class="n">all</span><span class="p">()</span> <span class="o">==</span> <span class="p">[</span>
<span class="p">(</span>
<span class="mi">1</span><span class="p">,</span>
<span class="n">times</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">-</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">),</span>
<span class="n">times</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">+</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">),</span>
<span class="s2">"child 1"</span><span class="p">,</span>
<span class="p">)</span>
<span class="p">]</span>
<span class="n">now</span> <span class="o">=</span> <span class="n">time_passes</span><span class="p">(</span><span class="n">s</span><span class="p">)</span>
<span class="n">p1_check</span> <span class="o">=</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Parent</span><span class="p">)</span><span class="o">.</span><span class="n">first</span><span class="p">()</span>
<span class="k">assert</span> <span class="n">p1_check</span> <span class="ow">is</span> <span class="n">p1</span>
<span class="k">assert</span> <span class="n">p1_check</span><span class="o">.</span><span class="n">child</span> <span class="ow">is</span> <span class="n">c1</span>
<span class="n">p1</span><span class="o">.</span><span class="n">child</span><span class="o">.</span><span class="n">data</span> <span class="o">=</span> <span class="s2">"elvis presley"</span>
<span class="n">s</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="n">p2_check</span> <span class="o">=</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Parent</span><span class="p">)</span><span class="o">.</span><span class="n">first</span><span class="p">()</span>
<span class="k">assert</span> <span class="n">p2_check</span> <span class="ow">is</span> <span class="n">p1_check</span>
<span class="n">c2_check</span> <span class="o">=</span> <span class="n">p2_check</span><span class="o">.</span><span class="n">child</span>
<span class="c1"># same object</span>
<span class="k">assert</span> <span class="n">p2_check</span><span class="o">.</span><span class="n">child</span> <span class="ow">is</span> <span class="n">c1</span>
<span class="c1"># new data</span>
<span class="k">assert</span> <span class="n">c1</span><span class="o">.</span><span class="n">data</span> <span class="o">==</span> <span class="s2">"elvis presley"</span>
<span class="c1"># new end time</span>
<span class="k">assert</span> <span class="n">c1</span><span class="o">.</span><span class="n">end</span> <span class="o">==</span> <span class="n">now</span> <span class="o">+</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">2</span><span class="p">)</span>
<span class="c1"># assert raw DB data</span>
<span class="k">assert</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Parent</span><span class="o">.</span><span class="n">__table__</span><span class="p">)</span><span class="o">.</span><span class="n">all</span><span class="p">()</span> <span class="o">==</span> <span class="p">[</span>
<span class="p">(</span>
<span class="mi">1</span><span class="p">,</span>
<span class="n">times</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">-</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">),</span>
<span class="n">times</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">+</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">),</span>
<span class="s2">"c1"</span><span class="p">,</span>
<span class="mi">1</span><span class="p">,</span>
<span class="p">)</span>
<span class="p">]</span>
<span class="k">assert</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Child</span><span class="o">.</span><span class="n">__table__</span><span class="p">)</span><span class="o">.</span><span class="n">order_by</span><span class="p">(</span><span class="n">Child</span><span class="o">.</span><span class="n">end</span><span class="p">)</span><span class="o">.</span><span class="n">all</span><span class="p">()</span> <span class="o">==</span> <span class="p">[</span>
<span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">times</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">-</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">),</span> <span class="n">times</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="s2">"child 1"</span><span class="p">),</span>
<span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">times</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="n">times</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">+</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">2</span><span class="p">),</span> <span class="s2">"elvis presley"</span><span class="p">),</span>
<span class="p">]</span>
<span class="n">now</span> <span class="o">=</span> <span class="n">time_passes</span><span class="p">(</span><span class="n">s</span><span class="p">)</span>
<span class="n">p1</span><span class="o">.</span><span class="n">data</span> <span class="o">=</span> <span class="s2">"c2 elvis presley"</span>
<span class="n">s</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="c1"># assert raw DB data. now there are two parent rows.</span>
<span class="k">assert</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Parent</span><span class="o">.</span><span class="n">__table__</span><span class="p">)</span><span class="o">.</span><span class="n">order_by</span><span class="p">(</span><span class="n">Parent</span><span class="o">.</span><span class="n">end</span><span class="p">)</span><span class="o">.</span><span class="n">all</span><span class="p">()</span> <span class="o">==</span> <span class="p">[</span>
<span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">times</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">-</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">),</span> <span class="n">times</span><span class="p">[</span><span class="mi">2</span><span class="p">],</span> <span class="s2">"c1"</span><span class="p">,</span> <span class="mi">1</span><span class="p">),</span>
<span class="p">(</span>
<span class="mi">1</span><span class="p">,</span>
<span class="n">times</span><span class="p">[</span><span class="mi">2</span><span class="p">],</span>
<span class="n">times</span><span class="p">[</span><span class="mi">2</span><span class="p">]</span> <span class="o">+</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">2</span><span class="p">),</span>
<span class="s2">"c2 elvis presley"</span><span class="p">,</span>
<span class="mi">1</span><span class="p">,</span>
<span class="p">),</span>
<span class="p">]</span>
<span class="k">assert</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Child</span><span class="o">.</span><span class="n">__table__</span><span class="p">)</span><span class="o">.</span><span class="n">order_by</span><span class="p">(</span><span class="n">Child</span><span class="o">.</span><span class="n">end</span><span class="p">)</span><span class="o">.</span><span class="n">all</span><span class="p">()</span> <span class="o">==</span> <span class="p">[</span>
<span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">times</span><span class="p">[</span><span class="mi">0</span><span class="p">]</span> <span class="o">-</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">3</span><span class="p">),</span> <span class="n">times</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="s2">"child 1"</span><span class="p">),</span>
<span class="p">(</span><span class="mi">1</span><span class="p">,</span> <span class="n">times</span><span class="p">[</span><span class="mi">1</span><span class="p">],</span> <span class="n">times</span><span class="p">[</span><span class="mi">1</span><span class="p">]</span> <span class="o">+</span> <span class="n">datetime</span><span class="o">.</span><span class="n">timedelta</span><span class="p">(</span><span class="n">days</span><span class="o">=</span><span class="mi">2</span><span class="p">),</span> <span class="s2">"elvis presley"</span><span class="p">),</span>
<span class="p">]</span>
<span class="c1"># add some more rows to test that these aren't coming back for</span>
<span class="c1"># queries</span>
<span class="n">s</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">Parent</span><span class="p">(</span><span class="nb">id</span><span class="o">=</span><span class="mi">2</span><span class="p">,</span> <span class="n">data</span><span class="o">=</span><span class="s2">"unrelated"</span><span class="p">,</span> <span class="n">child</span><span class="o">=</span><span class="n">Child</span><span class="p">(</span><span class="nb">id</span><span class="o">=</span><span class="mi">2</span><span class="p">,</span> <span class="n">data</span><span class="o">=</span><span class="s2">"unrelated"</span><span class="p">)))</span>
<span class="n">s</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="c1"># Query only knows about one parent for id=1</span>
<span class="n">p3_check</span> <span class="o">=</span> <span class="n">s</span><span class="o">.</span><span class="n">query</span><span class="p">(</span><span class="n">Parent</span><span class="p">)</span><span class="o">.</span><span class="n">filter_by</span><span class="p">(</span><span class="nb">id</span><span class="o">=</span><span class="mi">1</span><span class="p">)</span><span class="o">.</span><span class="n">one</span><span class="p">()</span>
<span class="k">assert</span> <span class="n">p3_check</span> <span class="ow">is</span> <span class="n">p1</span>
<span class="k">assert</span> <span class="n">p3_check</span><span class="o">.</span><span class="n">child</span> <span class="ow">is</span> <span class="n">c1</span>
<span class="c1"># and one child.</span>
<span class="n">c3_check</span> <span class="o">=</span> <span class="n">s</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">filter</span><span class="p">(</span><span class="n">Child</span><span class="o">.</span><span class="n">parent</span> <span class="o">==</span> <span class="n">p3_check</span><span class="p">)</span><span class="o">.</span><span class="n">one</span><span class="p">()</span>
<span class="k">assert</span> <span class="n">c3_check</span> <span class="ow">is</span> <span class="n">c1</span>
<span class="c1"># one child one parent....</span>
<span class="n">c3_check</span> <span class="o">=</span> <span class="p">(</span>
<span class="n">s</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">join</span><span class="p">(</span><span class="n">Parent</span><span class="o">.</span><span class="n">child</span><span class="p">)</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span><span class="n">Parent</span><span class="o">.</span><span class="n">id</span> <span class="o">==</span> <span class="n">p3_check</span><span class="o">.</span><span class="n">id</span><span class="p">)</span><span class="o">.</span><span class="n">one</span><span class="p">()</span>
<span class="p">)</span></pre></div>
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distrib
>
Mageia
>
7
>
armv7hl
>
media
>
core-updates
>
by-pkgid
>
b0b6ffab06cbeede296e36ce94734bf8
>
files
>
704
