File: //usr/share/doc/python-sqlalchemy-0.9.8/doc/_modules/examples/elementtree/pickle.html
<!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>
examples.elementtree.pickle
—
SQLAlchemy 0.9 Documentation
</title>
<!-- begin iterate through SQLA + sphinx environment css_files -->
<link rel="stylesheet" href="../../../_static/pygments.css" type="text/css" />
<link rel="stylesheet" href="../../../_static/docs.css" type="text/css" />
<link rel="stylesheet" href="../../../_static/sphinx_paramlinks.css" type="text/css" />
<link rel="stylesheet" href="../../../_static/changelog.css" type="text/css" />
<!-- end iterate through SQLA + sphinx environment css_files -->
<!-- begin layout.mako headers -->
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT: '../../../',
VERSION: '0.9.8',
COLLAPSE_MODINDEX: false,
FILE_SUFFIX: '.html'
};
</script>
<!-- begin iterate through sphinx environment script_files -->
<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>
<!-- end iterate through sphinx environment script_files -->
<script type="text/javascript" src="../../../_static/detectmobile.js"></script>
<script type="text/javascript" src="../../../_static/init.js"></script>
<link rel="index" title="Index" href="../../../genindex.html" />
<link rel="search" title="Search" href="../../../search.html" />
<link rel="copyright" title="Copyright" href="../../../copyright.html" />
<link rel="top" title="SQLAlchemy 0.9 Documentation" href="../../../index.html" />
<link rel="up" title="Module code" href="../../index.html" />
<!-- end layout.mako headers -->
</head>
<body>
<div id="docs-container">
<div id="docs-top-navigation-container" class="body-background">
<div id="docs-header">
<div id="docs-version-header">
Release: <span class="version-num">0.9.8</span> | Release Date: October 13, 2014
</div>
<h1>SQLAlchemy 0.9 Documentation</h1>
</div>
</div>
<div id="docs-body-container">
<div id="fixed-sidebar" class="">
<div id="index-nav">
<form class="search" action="../../../search.html" method="get">
<input type="text" name="q" size="12" /> <input type="submit" value="Search" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
<p>
<a href="../../../index.html">Contents</a> |
<a href="../../../genindex.html">Index</a>
</p>
</div>
</div>
<div id="docs-body" class="" >
<h1>Source code for examples.elementtree.pickle</h1><div class="highlight"><pre>
<span class="sd">"""illustrates a quick and dirty way to persist an XML document expressed using ElementTree and pickle.</span>
<span class="sd">This is a trivial example using PickleType to marshal/unmarshal the ElementTree</span>
<span class="sd">document into a binary column. Compare to explicit.py which stores the individual components of the ElementTree</span>
<span class="sd">structure in distinct rows using two additional mapped entities. Note that the usage of both</span>
<span class="sd">styles of persistence are identical, as is the structure of the main Document class.</span>
<span class="sd">"""</span>
<span class="kn">from</span> <span class="nn">sqlalchemy</span> <span class="kn">import</span> <span class="p">(</span><span class="n">create_engine</span><span class="p">,</span> <span class="n">MetaData</span><span class="p">,</span> <span class="n">Table</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">PickleType</span><span class="p">)</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="kn">import</span> <span class="n">mapper</span><span class="p">,</span> <span class="n">Session</span>
<span class="kn">import</span> <span class="nn">sys</span><span class="o">,</span> <span class="nn">os</span>
<span class="kn">from</span> <span class="nn">xml.etree</span> <span class="kn">import</span> <span class="n">ElementTree</span>
<span class="n">e</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">meta</span> <span class="o">=</span> <span class="n">MetaData</span><span class="p">()</span>
<span class="c"># setup a comparator for the PickleType since it's a mutable</span>
<span class="c"># element.</span>
<span class="k">def</span> <span class="nf">are_elements_equal</span><span class="p">(</span><span class="n">x</span><span class="p">,</span> <span class="n">y</span><span class="p">):</span>
<span class="k">return</span> <span class="n">x</span> <span class="o">==</span> <span class="n">y</span>
<span class="c"># stores a top level record of an XML document.</span>
<span class="c"># the "element" column will store the ElementTree document as a BLOB.</span>
<span class="n">documents</span> <span class="o">=</span> <span class="n">Table</span><span class="p">(</span><span class="s">'documents'</span><span class="p">,</span> <span class="n">meta</span><span class="p">,</span>
<span class="n">Column</span><span class="p">(</span><span class="s">'document_id'</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">Column</span><span class="p">(</span><span class="s">'filename'</span><span class="p">,</span> <span class="n">String</span><span class="p">(</span><span class="mi">30</span><span class="p">),</span> <span class="n">unique</span><span class="o">=</span><span class="bp">True</span><span class="p">),</span>
<span class="n">Column</span><span class="p">(</span><span class="s">'element'</span><span class="p">,</span> <span class="n">PickleType</span><span class="p">(</span><span class="n">comparator</span><span class="o">=</span><span class="n">are_elements_equal</span><span class="p">))</span>
<span class="p">)</span>
<span class="n">meta</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="c"># our document class. contains a string name,</span>
<span class="c"># and the ElementTree root element.</span>
<span class="k">class</span> <span class="nc">Document</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">name</span><span class="p">,</span> <span class="n">element</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">filename</span> <span class="o">=</span> <span class="n">name</span>
<span class="bp">self</span><span class="o">.</span><span class="n">element</span> <span class="o">=</span> <span class="n">element</span>
<span class="c"># setup mapper.</span>
<span class="n">mapper</span><span class="p">(</span><span class="n">Document</span><span class="p">,</span> <span class="n">documents</span><span class="p">)</span>
<span class="c">###### time to test ! #########</span>
<span class="c"># get ElementTree document</span>
<span class="n">filename</span> <span class="o">=</span> <span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">join</span><span class="p">(</span><span class="n">os</span><span class="o">.</span><span class="n">path</span><span class="o">.</span><span class="n">dirname</span><span class="p">(</span><span class="n">__file__</span><span class="p">),</span> <span class="s">"test.xml"</span><span class="p">)</span>
<span class="n">doc</span> <span class="o">=</span> <span class="n">ElementTree</span><span class="o">.</span><span class="n">parse</span><span class="p">(</span><span class="n">filename</span><span class="p">)</span>
<span class="c"># save to DB</span>
<span class="n">session</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">session</span><span class="o">.</span><span class="n">add</span><span class="p">(</span><span class="n">Document</span><span class="p">(</span><span class="s">"test.xml"</span><span class="p">,</span> <span class="n">doc</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="c"># restore</span>
<span class="n">document</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">Document</span><span class="p">)</span><span class="o">.</span><span class="n">filter_by</span><span class="p">(</span><span class="n">filename</span><span class="o">=</span><span class="s">"test.xml"</span><span class="p">)</span><span class="o">.</span><span class="n">first</span><span class="p">()</span>
<span class="c"># print</span>
<span class="n">document</span><span class="o">.</span><span class="n">element</span><span class="o">.</span><span class="n">write</span><span class="p">(</span><span class="n">sys</span><span class="o">.</span><span class="n">stdout</span><span class="p">)</span></pre></div>
</div>
</div>
<div id="docs-bottom-navigation" class="docs-navigation-links">
<div id="docs-copyright">
© <a href="../../../copyright.html">Copyright</a> 2007-2014, the SQLAlchemy authors and contributors.
Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.2b1.
</div>
</div>
</div>
</body>
</html>