<!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.large_collection.large_collection
—
SQLAlchemy 1.2 Documentation
</title>
<!-- begin iterate through site-imported + 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/changelog.css" type="text/css" />
<link rel="stylesheet" href="../../../_static/sphinx_paramlinks.css" type="text/css" />
<!-- end iterate through site-imported + sphinx environment css_files -->
<!-- begin layout.mako headers -->
<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 1.2 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">1.2.19</span>
| Release Date: April 15, 2019
</div>
<h1>SQLAlchemy 1.2 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">
<label>
Search terms:
<input type="text" placeholder="search..." name="q" size="12" />
</label>
<input type="submit" value="Search" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
<p>
<a href="../../../contents.html">Contents</a> |
<a href="../../../genindex.html">Index</a>
</p>
</div>
</div>
<div id="docs-body" class="" >
<h1>Source code for examples.large_collection.large_collection</h1><div class="highlight"><pre>
<span></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">ForeignKey</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">MetaData</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</span> <span class="k">import</span> <span class="n">Table</span>
<span class="kn">from</span> <span class="nn">sqlalchemy.orm</span> <span class="k">import</span> <span class="n">mapper</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">sessionmaker</span>
<span class="n">meta</span> <span class="o">=</span> <span class="n">MetaData</span><span class="p">()</span>
<span class="n">org_table</span> <span class="o">=</span> <span class="n">Table</span><span class="p">(</span>
<span class="s2">"organizations"</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="s2">"org_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="kc">True</span><span class="p">),</span>
<span class="n">Column</span><span class="p">(</span><span class="s2">"org_name"</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">nullable</span><span class="o">=</span><span class="kc">False</span><span class="p">,</span> <span class="n">key</span><span class="o">=</span><span class="s2">"name"</span><span class="p">),</span>
<span class="n">mysql_engine</span><span class="o">=</span><span class="s2">"InnoDB"</span><span class="p">,</span>
<span class="p">)</span>
<span class="n">member_table</span> <span class="o">=</span> <span class="n">Table</span><span class="p">(</span>
<span class="s2">"members"</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="s2">"member_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="kc">True</span><span class="p">),</span>
<span class="n">Column</span><span class="p">(</span><span class="s2">"member_name"</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">nullable</span><span class="o">=</span><span class="kc">False</span><span class="p">,</span> <span class="n">key</span><span class="o">=</span><span class="s2">"name"</span><span class="p">),</span>
<span class="n">Column</span><span class="p">(</span>
<span class="s2">"org_id"</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="s2">"organizations.org_id"</span><span class="p">,</span> <span class="n">ondelete</span><span class="o">=</span><span class="s2">"CASCADE"</span><span class="p">),</span>
<span class="p">),</span>
<span class="n">mysql_engine</span><span class="o">=</span><span class="s2">"InnoDB"</span><span class="p">,</span>
<span class="p">)</span>
<span class="k">class</span> <span class="nc">Organization</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="bp">self</span><span class="o">.</span><span class="n">name</span> <span class="o">=</span> <span class="n">name</span>
<span class="k">class</span> <span class="nc">Member</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="bp">self</span><span class="o">.</span><span class="n">name</span> <span class="o">=</span> <span class="n">name</span>
<span class="n">mapper</span><span class="p">(</span>
<span class="n">Organization</span><span class="p">,</span>
<span class="n">org_table</span><span class="p">,</span>
<span class="n">properties</span><span class="o">=</span><span class="p">{</span>
<span class="s2">"members"</span><span class="p">:</span> <span class="n">relationship</span><span class="p">(</span>
<span class="n">Member</span><span class="p">,</span>
<span class="c1"># Organization.members will be a Query object - no loading</span>
<span class="c1"># of the entire collection occurs unless requested</span>
<span class="n">lazy</span><span class="o">=</span><span class="s2">"dynamic"</span><span class="p">,</span>
<span class="c1"># Member objects "belong" to their parent, are deleted when</span>
<span class="c1"># removed from the collection</span>
<span class="n">cascade</span><span class="o">=</span><span class="s2">"all, delete-orphan"</span><span class="p">,</span>
<span class="c1"># "delete, delete-orphan" cascade does not load in objects on</span>
<span class="c1"># delete, allows ON DELETE CASCADE to handle it.</span>
<span class="c1"># this only works with a database that supports ON DELETE CASCADE -</span>
<span class="c1"># *not* sqlite or MySQL with MyISAM</span>
<span class="n">passive_deletes</span><span class="o">=</span><span class="kc">True</span><span class="p">,</span>
<span class="p">)</span>
<span class="p">},</span>
<span class="p">)</span>
<span class="n">mapper</span><span class="p">(</span><span class="n">Member</span><span class="p">,</span> <span class="n">member_table</span><span class="p">)</span>
<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s2">"__main__"</span><span class="p">:</span>
<span class="n">engine</span> <span class="o">=</span> <span class="n">create_engine</span><span class="p">(</span>
<span class="s2">"postgresql://scott:tiger@localhost/test"</span><span class="p">,</span> <span class="n">echo</span><span class="o">=</span><span class="kc">True</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">engine</span><span class="p">)</span>
<span class="c1"># expire_on_commit=False means the session contents</span>
<span class="c1"># will not get invalidated after commit.</span>
<span class="n">sess</span> <span class="o">=</span> <span class="n">sessionmaker</span><span class="p">(</span><span class="n">engine</span><span class="p">,</span> <span class="n">expire_on_commit</span><span class="o">=</span><span class="kc">False</span><span class="p">)()</span>
<span class="c1"># create org with some members</span>
<span class="n">org</span> <span class="o">=</span> <span class="n">Organization</span><span class="p">(</span><span class="s2">"org one"</span><span class="p">)</span>
<span class="n">org</span><span class="o">.</span><span class="n">members</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">Member</span><span class="p">(</span><span class="s2">"member one"</span><span class="p">))</span>
<span class="n">org</span><span class="o">.</span><span class="n">members</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">Member</span><span class="p">(</span><span class="s2">"member two"</span><span class="p">))</span>
<span class="n">org</span><span class="o">.</span><span class="n">members</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">Member</span><span class="p">(</span><span class="s2">"member three"</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">org</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"-------------------------</span><span class="se">\n</span><span class="s2">flush one - save org + 3 members</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
<span class="n">sess</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="c1"># the 'members' collection is a Query. it issues</span>
<span class="c1"># SQL as needed to load subsets of the collection.</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"-------------------------</span><span class="se">\n</span><span class="s2">load subset of members</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
<span class="n">members</span> <span class="o">=</span> <span class="n">org</span><span class="o">.</span><span class="n">members</span><span class="o">.</span><span class="n">filter</span><span class="p">(</span><span class="n">member_table</span><span class="o">.</span><span class="n">c</span><span class="o">.</span><span class="n">name</span><span class="o">.</span><span class="n">like</span><span class="p">(</span><span class="s2">"%member t%"</span><span class="p">))</span><span class="o">.</span><span class="n">all</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="n">members</span><span class="p">)</span>
<span class="c1"># new Members can be appended without any</span>
<span class="c1"># SQL being emitted to load the full collection</span>
<span class="n">org</span><span class="o">.</span><span class="n">members</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">Member</span><span class="p">(</span><span class="s2">"member four"</span><span class="p">))</span>
<span class="n">org</span><span class="o">.</span><span class="n">members</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">Member</span><span class="p">(</span><span class="s2">"member five"</span><span class="p">))</span>
<span class="n">org</span><span class="o">.</span><span class="n">members</span><span class="o">.</span><span class="n">append</span><span class="p">(</span><span class="n">Member</span><span class="p">(</span><span class="s2">"member six"</span><span class="p">))</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"-------------------------</span><span class="se">\n</span><span class="s2">flush two - save 3 more members</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
<span class="n">sess</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="c1"># delete the object. Using ON DELETE CASCADE</span>
<span class="c1"># SQL is only emitted for the head row - the Member rows</span>
<span class="c1"># disappear automatically without the need for additional SQL.</span>
<span class="n">sess</span><span class="o">.</span><span class="n">delete</span><span class="p">(</span><span class="n">org</span><span class="p">)</span>
<span class="nb">print</span><span class="p">(</span>
<span class="s2">"-------------------------</span><span class="se">\n</span><span class="s2">flush three - delete org, "</span>
<span class="s2">"delete members in one statement</span><span class="se">\n</span><span class="s2">"</span>
<span class="p">)</span>
<span class="n">sess</span><span class="o">.</span><span class="n">commit</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"-------------------------</span><span class="se">\n</span><span class="s2">no Member rows should remain:</span><span class="se">\n</span><span class="s2">"</span><span class="p">)</span>
<span class="nb">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">Member</span><span class="p">)</span><span class="o">.</span><span class="n">count</span><span class="p">())</span>
<span class="n">sess</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="nb">print</span><span class="p">(</span><span class="s2">"------------------------</span><span class="se">\n</span><span class="s2">done. dropping tables."</span><span class="p">)</span>
<span class="n">meta</span><span class="o">.</span><span class="n">drop_all</span><span class="p">(</span><span class="n">engine</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> 2007-2019, the SQLAlchemy authors and contributors.
Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 2.0.1.
</div>
</div>
</div>
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT: '../../../',
VERSION: '1.2.19',
COLLAPSE_MODINDEX: false,
FILE_SUFFIX: '.html'
};
</script>
<script type="text/javascript" id="documentation_options" data-url_root="../../../" src="../../../_static/documentation_options.js"></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>
<script type="text/javascript" src="../../../_static/language_data.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>
</body>
</html>
distrib
>
Mageia
>
7
>
armv7hl
>
media
>
core-updates
>
by-pkgid
>
b0b6ffab06cbeede296e36ce94734bf8
>
files
>
681
