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<h1>Source code for apsw.bestpractice</h1><div class="highlight"><pre>
<span></span><span class="c1">#</span>
<span class="sd">"""Ensure SQLite usage prevents common mistakes, and get best performance."""</span>
<span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">annotations</span>
<span class="kn">from</span> <span class="nn">typing</span> <span class="kn">import</span> <span class="n">Callable</span>
<span class="kn">import</span> <span class="nn">apsw</span>
<span class="kn">import</span> <span class="nn">apsw.ext</span>
<div class="viewcode-block" id="connection_wal">
<a class="viewcode-back" href="../../bestpractice.html#apsw.bestpractice.connection_wal">[docs]</a>
<span class="k">def</span> <span class="nf">connection_wal</span><span class="p">(</span><span class="n">connection</span><span class="p">:</span> <span class="n">apsw</span><span class="o">.</span><span class="n">Connection</span><span class="p">)</span> <span class="o">-></span> <span class="kc">None</span><span class="p">:</span>
<span class="w"> </span><span class="sd">"""Turns on write ahead logging</span>
<span class="sd"> Reduces contention and improves write performance. WAL is</span>
<span class="sd"> `described here <https://www.sqlite.org/wal.html>`__.</span>
<span class="sd"> """</span>
<span class="n">connection</span><span class="o">.</span><span class="n">pragma</span><span class="p">(</span><span class="s2">"journal_mode"</span><span class="p">,</span> <span class="s2">"wal"</span><span class="p">)</span></div>
<div class="viewcode-block" id="connection_busy_timeout">
<a class="viewcode-back" href="../../bestpractice.html#apsw.bestpractice.connection_busy_timeout">[docs]</a>
<span class="k">def</span> <span class="nf">connection_busy_timeout</span><span class="p">(</span><span class="n">connection</span><span class="p">:</span> <span class="n">apsw</span><span class="o">.</span><span class="n">Connection</span><span class="p">,</span> <span class="n">duration_ms</span><span class="p">:</span> <span class="nb">int</span> <span class="o">=</span> <span class="mi">100</span><span class="p">)</span> <span class="o">-></span> <span class="kc">None</span><span class="p">:</span>
<span class="w"> </span><span class="sd">"""Sets a short busy timeout</span>
<span class="sd"> :param duration_ms: How many thousandths of a second to wait</span>
<span class="sd"> When another thread or process has locked the database, SQLite</span>
<span class="sd"> immediately raises :exc:`apsw.BusyError`. Changing the `busy</span>
<span class="sd"> timeout <https://www.sqlite.org/c3ref/busy_timeout.html>`__ gives</span>
<span class="sd"> a grace period during which SQLite retries.</span>
<span class="sd"> """</span>
<span class="n">connection</span><span class="o">.</span><span class="n">set_busy_timeout</span><span class="p">(</span><span class="n">duration_ms</span><span class="p">)</span></div>
<div class="viewcode-block" id="connection_enable_foreign_keys">
<a class="viewcode-back" href="../../bestpractice.html#apsw.bestpractice.connection_enable_foreign_keys">[docs]</a>
<span class="k">def</span> <span class="nf">connection_enable_foreign_keys</span><span class="p">(</span><span class="n">connection</span><span class="p">:</span> <span class="n">apsw</span><span class="o">.</span><span class="n">Connection</span><span class="p">)</span> <span class="o">-></span> <span class="kc">None</span><span class="p">:</span>
<span class="w"> </span><span class="sd">"""Enables foreign key constraints</span>
<span class="sd"> `Foreign keys <https://www.sqlite.org/foreignkeys.html>`__ need to</span>
<span class="sd"> `be enabled <https://www.sqlite.org/foreignkeys.html#fk_enable>`__</span>
<span class="sd"> to have an effect.</span>
<span class="sd"> """</span>
<span class="n">connection</span><span class="o">.</span><span class="n">pragma</span><span class="p">(</span><span class="s2">"foreign_keys"</span><span class="p">,</span> <span class="s2">"ON"</span><span class="p">)</span></div>
<div class="viewcode-block" id="connection_dqs">
<a class="viewcode-back" href="../../bestpractice.html#apsw.bestpractice.connection_dqs">[docs]</a>
<span class="k">def</span> <span class="nf">connection_dqs</span><span class="p">(</span><span class="n">connection</span><span class="p">:</span> <span class="n">apsw</span><span class="o">.</span><span class="n">Connection</span><span class="p">)</span> <span class="o">-></span> <span class="kc">None</span><span class="p">:</span>
<span class="w"> </span><span class="sd">"""Double quotes are for identifiers only, not strings</span>
<span class="sd"> Turns off `allowing double quoted strings</span>
<span class="sd"> <https://www.sqlite.org/quirks.html#dblquote>`__ if they don't</span>
<span class="sd"> match any identifier (column/table names etc), making it an error</span>
<span class="sd"> to use double quotes around strings. SQL strings use single</span>
<span class="sd"> quotes.</span>
<span class="sd"> """</span>
<span class="n">connection</span><span class="o">.</span><span class="n">config</span><span class="p">(</span><span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_DBCONFIG_DQS_DML</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span>
<span class="n">connection</span><span class="o">.</span><span class="n">config</span><span class="p">(</span><span class="n">apsw</span><span class="o">.</span><span class="n">SQLITE_DBCONFIG_DQS_DDL</span><span class="p">,</span> <span class="mi">0</span><span class="p">)</span></div>
<div class="viewcode-block" id="library_logging">
<a class="viewcode-back" href="../../bestpractice.html#apsw.bestpractice.library_logging">[docs]</a>
<span class="k">def</span> <span class="nf">library_logging</span><span class="p">()</span> <span class="o">-></span> <span class="kc">None</span><span class="p">:</span>
<span class="w"> </span><span class="sd">"""Forwards SQLite logging to Python logging module</span>
<span class="sd"> See :meth:`apsw.ext.log_sqlite`</span>
<span class="sd"> """</span>
<span class="n">apsw</span><span class="o">.</span><span class="n">ext</span><span class="o">.</span><span class="n">log_sqlite</span><span class="p">()</span></div>
<span class="n">recommended</span><span class="p">:</span> <span class="nb">tuple</span><span class="p">[</span><span class="n">Callable</span><span class="p">,</span> <span class="o">...</span><span class="p">]</span> <span class="o">=</span> <span class="p">(</span>
<span class="n">connection_wal</span><span class="p">,</span>
<span class="n">connection_busy_timeout</span><span class="p">,</span>
<span class="n">connection_enable_foreign_keys</span><span class="p">,</span>
<span class="n">connection_dqs</span><span class="p">,</span>
<span class="n">library_logging</span><span class="p">,</span>
<span class="p">)</span>
<span class="s2">"All of them"</span>
<div class="viewcode-block" id="apply">
<a class="viewcode-back" href="../../bestpractice.html#apsw.bestpractice.apply">[docs]</a>
<span class="k">def</span> <span class="nf">apply</span><span class="p">(</span><span class="n">which</span><span class="p">:</span> <span class="nb">tuple</span><span class="p">[</span><span class="n">Callable</span><span class="p">,</span> <span class="o">...</span><span class="p">])</span> <span class="o">-></span> <span class="kc">None</span><span class="p">:</span>
<span class="s2">"Applies library immediately and connection to new connections"</span>
<span class="n">hooks</span> <span class="p">:</span> <span class="nb">list</span><span class="p">[</span><span class="n">Callable</span><span class="p">]</span> <span class="o">=</span> <span class="p">[]</span>
<span class="k">for</span> <span class="n">func</span> <span class="ow">in</span> <span class="n">which</span><span class="p">:</span>
<span class="k">if</span> <span class="n">func</span><span class="o">.</span><span class="vm">__name__</span><span class="o">.</span><span class="n">startswith</span><span class="p">(</span><span class="s2">"connection_"</span><span class="p">):</span>
<span class="n">hooks</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">func</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">func</span><span class="p">()</span>
<span class="k">def</span> <span class="nf">best_practise_connection_apply</span><span class="p">(</span><span class="n">connection</span><span class="p">:</span> <span class="n">apsw</span><span class="o">.</span><span class="n">Connection</span><span class="p">)</span> <span class="o">-></span> <span class="kc">None</span><span class="p">:</span>
<span class="k">for</span> <span class="n">func</span> <span class="ow">in</span> <span class="n">hooks</span><span class="p">:</span>
<span class="n">func</span><span class="p">(</span><span class="n">connection</span><span class="p">)</span>
<span class="n">apsw</span><span class="o">.</span><span class="n">connection_hooks</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">best_practise_connection_apply</span><span class="p">)</span></div>
</pre></div>
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