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diff --git a/app/static/doc/flask-docs/tutorial/dbinit.html b/app/static/doc/flask-docs/tutorial/dbinit.html new file mode 100644 index 0000000..413914e --- /dev/null +++ b/app/static/doc/flask-docs/tutorial/dbinit.html @@ -0,0 +1,166 @@ + +<!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"> + <head> + <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> + + <title>Step 3: Creating The Database — Flask 0.8 documentation</title> + + <link rel="stylesheet" href="../_static/flasky.css" type="text/css" /> + <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> + + <script type="text/javascript"> + var DOCUMENTATION_OPTIONS = { + URL_ROOT: '../', + VERSION: '0.8', + 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="top" title="Flask 0.8 documentation" href="../index.html" /> + <link rel="up" title="Tutorial" href="index.html" /> + <link rel="next" title="Step 4: Request Database Connections" href="dbcon.html" /> + <link rel="prev" title="Step 2: Application Setup Code" href="setup.html" /> + + + <link rel="apple-touch-icon" href="../_static/touch-icon.png" /> + + <link media="only screen and (max-device-width: 480px)" href="../_static/small_flask.css" type= "text/css" rel="stylesheet" /> + + </head> + <body> + <div class="related"> + <h3>Navigation</h3> + <ul> + <li class="right" style="margin-right: 10px"> + <a href="../genindex.html" title="General Index" + accesskey="I">index</a></li> + <li class="right" > + <a href="dbcon.html" title="Step 4: Request Database Connections" + accesskey="N">next</a> |</li> + <li class="right" > + <a href="setup.html" title="Step 2: Application Setup Code" + accesskey="P">previous</a> |</li> + <li><a href="../index.html">Flask 0.8 documentation</a> »</li> + <li><a href="index.html" accesskey="U">Tutorial</a> »</li> + </ul> + </div> + + <div class="document"> + <div class="documentwrapper"> + <div class="bodywrapper"> + <div class="body"> + + <div class="section" id="step-3-creating-the-database"> +<span id="tutorial-dbinit"></span><h1>Step 3: Creating The Database<a class="headerlink" href="#step-3-creating-the-database" title="Permalink to this headline">ΒΆ</a></h1> +<p>Flaskr is a database powered application as outlined earlier, and more +precisely, an application powered by a relational database system. Such +systems need a schema that tells them how to store that information. So +before starting the server for the first time it’s important to create +that schema.</p> +<p>Such a schema can be created by piping the <cite>schema.sql</cite> file into the +<cite>sqlite3</cite> command as follows:</p> +<div class="highlight-python"><div class="highlight"><pre><span class="n">sqlite3</span> <span class="o">/</span><span class="n">tmp</span><span class="o">/</span><span class="n">flaskr</span><span class="o">.</span><span class="n">db</span> <span class="o"><</span> <span class="n">schema</span><span class="o">.</span><span class="n">sql</span> +</pre></div> +</div> +<p>The downside of this is that it requires the sqlite3 command to be +installed which is not necessarily the case on every system. Also one has +to provide the path to the database there which leaves some place for +errors. It’s a good idea to add a function that initializes the database +for you to the application.</p> +<p>If you want to do that, you first have to import the +<a class="reference external" href="http://docs.python.org/dev/library/contextlib.html#contextlib.closing" title="(in Python v3.3)"><tt class="xref py py-func docutils literal"><span class="pre">contextlib.closing()</span></tt></a> function from the contextlib package. If you +want to use Python 2.5 it’s also necessary to enable the <cite>with</cite> statement +first (<cite>__future__</cite> imports must be the very first import):</p> +<div class="highlight-python"><div class="highlight"><pre><span class="kn">from</span> <span class="nn">__future__</span> <span class="kn">import</span> <span class="n">with_statement</span> +<span class="kn">from</span> <span class="nn">contextlib</span> <span class="kn">import</span> <span class="n">closing</span> +</pre></div> +</div> +<p>Next we can create a function called <cite>init_db</cite> that initializes the +database. For this we can use the <cite>connect_db</cite> function we defined +earlier. Just add that function below the <cite>connect_db</cite> function:</p> +<div class="highlight-python"><div class="highlight"><pre><span class="k">def</span> <span class="nf">init_db</span><span class="p">():</span> + <span class="k">with</span> <span class="n">closing</span><span class="p">(</span><span class="n">connect_db</span><span class="p">())</span> <span class="k">as</span> <span class="n">db</span><span class="p">:</span> + <span class="k">with</span> <span class="n">app</span><span class="o">.</span><span class="n">open_resource</span><span class="p">(</span><span class="s">'schema.sql'</span><span class="p">)</span> <span class="k">as</span> <span class="n">f</span><span class="p">:</span> + <span class="n">db</span><span class="o">.</span><span class="n">cursor</span><span class="p">()</span><span class="o">.</span><span class="n">executescript</span><span class="p">(</span><span class="n">f</span><span class="o">.</span><span class="n">read</span><span class="p">())</span> + <span class="n">db</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span> +</pre></div> +</div> +<p>The <a class="reference external" href="http://docs.python.org/dev/library/contextlib.html#contextlib.closing" title="(in Python v3.3)"><tt class="xref py py-func docutils literal"><span class="pre">closing()</span></tt></a> helper function allows us to keep a +connection open for the duration of the <cite>with</cite> block. The +<a class="reference internal" href="../api.html#flask.Flask.open_resource" title="flask.Flask.open_resource"><tt class="xref py py-func docutils literal"><span class="pre">open_resource()</span></tt></a> method of the application object +supports that functionality out of the box, so it can be used in the +<cite>with</cite> block directly. This function opens a file from the resource +location (your <cite>flaskr</cite> folder) and allows you to read from it. We are +using this here to execute a script on the database connection.</p> +<p>When we connect to a database we get a connection object (here called +<cite>db</cite>) that can give us a cursor. On that cursor there is a method to +execute a complete script. Finally we only have to commit the changes. +SQLite 3 and other transactional databases will not commit unless you +explicitly tell it to.</p> +<p>Now it is possible to create a database by starting up a Python shell and +importing and calling that function:</p> +<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">from</span> <span class="nn">flaskr</span> <span class="kn">import</span> <span class="n">init_db</span> +<span class="gp">>>> </span><span class="n">init_db</span><span class="p">()</span> +</pre></div> +</div> +<div class="admonition-troubleshooting admonition "> +<p class="first admonition-title">Troubleshooting</p> +<p class="last">If you get an exception later that a table cannot be found check that +you did call the <cite>init_db</cite> function and that your table names are +correct (singular vs. plural for example).</p> +</div> +<p>Continue with <a class="reference internal" href="dbcon.html#tutorial-dbcon"><em>Step 4: Request Database Connections</em></a></p> +</div> + + + </div> + </div> + </div> + <div class="sphinxsidebar"> + <div class="sphinxsidebarwrapper"><p class="logo"><a href="../index.html"> + <img class="logo" src="../_static/flask.png" alt="Logo"/> +</a></p><h3>Related Topics</h3> +<ul> + <li><a href="../index.html">Documentation overview</a><ul> + <li><a href="index.html">Tutorial</a><ul> + <li>Previous: <a href="setup.html" title="previous chapter">Step 2: Application Setup Code</a></li> + <li>Next: <a href="dbcon.html" title="next chapter">Step 4: Request Database Connections</a></li> + </ul></li> + </ul></li> +</ul> + <h3>This Page</h3> + <ul class="this-page-menu"> + <li><a href="../_sources/tutorial/dbinit.txt" + rel="nofollow">Show Source</a></li> + </ul> +<div id="searchbox" style="display: none"> + <h3>Quick search</h3> + <form class="search" action="../search.html" method="get"> + <input type="text" name="q" /> + <input type="submit" value="Go" /> + <input type="hidden" name="check_keywords" value="yes" /> + <input type="hidden" name="area" value="default" /> + </form> + <p class="searchtip" style="font-size: 90%"> + Enter search terms or a module, class or function name. + </p> +</div> +<script type="text/javascript">$('#searchbox').show(0);</script> + </div> + </div> + <div class="clearer"></div> + </div> + <div class="footer"> + © Copyright 2010, Armin Ronacher. + Created using <a href="http://sphinx.pocoo.org/">Sphinx</a>. + </div> + </body> +</html>
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