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<h1><a href="../index.html">Django v1.2 documentation</a></h1>
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<div class="yui-g" id="howto-initial-data">
<div class="section" id="s-providing-initial-data-for-models">
<span id="providing-initial-data-for-models"></span><h1>Providing initial data for models<a class="headerlink" href="#providing-initial-data-for-models" title="Permalink to this headline">¶</a></h1>
<p>It’s sometimes useful to pre-populate your database with hard-coded data when
you’re first setting up an app. There’s a couple of ways you can have Django
automatically create this data: you can provide <a class="reference internal" href="#providing-initial-data-with-fixtures">initial data via fixtures</a>, or
you can provide <a class="reference internal" href="#providing-initial-sql-data">initial data as SQL</a>.</p>
<p>In general, using a fixture is a cleaner method since it’s database-agnostic,
but initial SQL is also quite a bit more flexible.</p>
<div class="section" id="s-providing-initial-data-with-fixtures">
<span id="providing-initial-data-with-fixtures"></span><h2>Providing initial data with fixtures<a class="headerlink" href="#providing-initial-data-with-fixtures" title="Permalink to this headline">¶</a></h2>
<p>A fixture is a collection of data that Django knows how to import into a
database. The most straightforward way of creating a fixture if you’ve already
got some data is to use the <a class="reference internal" href="../ref/django-admin.html#django-admin-dumpdata"><tt class="xref std std-djadmin docutils literal"><span class="pre">manage.py</span> <span class="pre">dumpdata</span></tt></a> command.
Or, you can write fixtures by hand; fixtures can be written as XML, YAML, or
JSON documents. The <a class="reference internal" href="../topics/serialization.html"><em>serialization documentation</em></a>
has more details about each of these supported <a class="reference internal" href="../topics/serialization.html#serialization-formats"><em>serialization formats</em></a>.</p>
<p>As an example, though, here’s what a fixture for a simple <tt class="docutils literal"><span class="pre">Person</span></tt> model might
look like in JSON:</p>
<div class="highlight-js"><div class="highlight"><pre><span class="p">[</span>
<span class="p">{</span>
<span class="s2">"model"</span><span class="o">:</span> <span class="s2">"myapp.person"</span><span class="p">,</span>
<span class="s2">"pk"</span><span class="o">:</span> <span class="mi">1</span><span class="p">,</span>
<span class="s2">"fields"</span><span class="o">:</span> <span class="p">{</span>
<span class="s2">"first_name"</span><span class="o">:</span> <span class="s2">"John"</span><span class="p">,</span>
<span class="s2">"last_name"</span><span class="o">:</span> <span class="s2">"Lennon"</span>
<span class="p">}</span>
<span class="p">},</span>
<span class="p">{</span>
<span class="s2">"model"</span><span class="o">:</span> <span class="s2">"myapp.person"</span><span class="p">,</span>
<span class="s2">"pk"</span><span class="o">:</span> <span class="mi">2</span><span class="p">,</span>
<span class="s2">"fields"</span><span class="o">:</span> <span class="p">{</span>
<span class="s2">"first_name"</span><span class="o">:</span> <span class="s2">"Paul"</span><span class="p">,</span>
<span class="s2">"last_name"</span><span class="o">:</span> <span class="s2">"McCartney"</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="p">]</span>
</pre></div>
</div>
<p>And here's that same fixture as YAML:</p>
<div class="highlight-none"><div class="highlight"><pre>- model: myapp.person
pk: 1
fields:
first_name: John
last_name: Lennon
- model: myapp.person
pk: 2
fields:
first_name: Paul
last_name: McCartney
</pre></div>
</div>
<p>You'll store this data in a <tt class="docutils literal"><span class="pre">fixtures</span></tt> directory inside your app.</p>
<p>Loading data is easy: just call <a class="reference internal" href="../ref/django-admin.html#django-admin-loaddata"><tt class="xref std std-djadmin docutils literal"><span class="pre">manage.py</span> <span class="pre">loaddata</span> <span class="pre">fixturename</span></tt></a>, where <em>fixturename</em> is the name of the fixture file you've created.
Every time you run <a class="reference internal" href="../ref/django-admin.html#django-admin-loaddata"><tt class="xref std std-djadmin docutils literal"><span class="pre">loaddata</span></tt></a> the data will be read from the fixture
and re-loaded into the database. Note that this means that if you change one of
the rows created by a fixture and then run <a class="reference internal" href="../ref/django-admin.html#django-admin-loaddata"><tt class="xref std std-djadmin docutils literal"><span class="pre">loaddata</span></tt></a> again you'll
wipe out any changes you've made.</p>
<div class="section" id="s-automatically-loading-initial-data-fixtures">
<span id="automatically-loading-initial-data-fixtures"></span><h3>Automatically loading initial data fixtures<a class="headerlink" href="#automatically-loading-initial-data-fixtures" title="Permalink to this headline">¶</a></h3>
<p>If you create a fixture named <tt class="docutils literal"><span class="pre">initial_data.[xml/yaml/json]</span></tt>, that fixture will
be loaded every time you run <a class="reference internal" href="../ref/django-admin.html#django-admin-syncdb"><tt class="xref std std-djadmin docutils literal"><span class="pre">syncdb</span></tt></a>. This is extremely convenient,
but be careful: remember that the data will be refreshed <em>every time</em> you run
<a class="reference internal" href="../ref/django-admin.html#django-admin-syncdb"><tt class="xref std std-djadmin docutils literal"><span class="pre">syncdb</span></tt></a>. So don't use <tt class="docutils literal"><span class="pre">initial_data</span></tt> for data you'll want to edit.</p>
<div class="admonition-see-also admonition seealso">
<p class="first admonition-title">See also</p>
<p class="last">Fixtures are also used by the <a class="reference internal" href="../topics/testing.html#topics-testing-fixtures"><em>testing framework</em></a> to help set up a consistent test environment.</p>
</div>
</div>
</div>
<div class="section" id="s-providing-initial-sql-data">
<span id="s-initial-sql"></span><span id="providing-initial-sql-data"></span><span id="initial-sql"></span><h2>Providing initial SQL data<a class="headerlink" href="#providing-initial-sql-data" title="Permalink to this headline">¶</a></h2>
<p>Django provides a hook for passing the database arbitrary SQL that's executed
just after the CREATE TABLE statements when you run <a class="reference internal" href="../ref/django-admin.html#django-admin-syncdb"><tt class="xref std std-djadmin docutils literal"><span class="pre">syncdb</span></tt></a>. You can
use this hook to populate default records, or you could also create SQL
functions, views, triggers, etc.</p>
<p>The hook is simple: Django just looks for a file called <tt class="docutils literal"><span class="pre">sql/<modelname>.sql</span></tt>,
in your app directory, where <tt class="docutils literal"><span class="pre"><modelname></span></tt> is the model's name in lowercase.</p>
<p>So, if you had a <tt class="docutils literal"><span class="pre">Person</span></tt> model in an app called <tt class="docutils literal"><span class="pre">myapp</span></tt>, you could add
arbitrary SQL to the file <tt class="docutils literal"><span class="pre">sql/person.sql</span></tt> inside your <tt class="docutils literal"><span class="pre">myapp</span></tt> directory.
Here's an example of what the file might contain:</p>
<div class="highlight-sql"><div class="highlight"><pre><span class="k">INSERT</span> <span class="k">INTO</span> <span class="n">myapp_person</span> <span class="p">(</span><span class="n">first_name</span><span class="p">,</span> <span class="n">last_name</span><span class="p">)</span> <span class="k">VALUES</span> <span class="p">(</span><span class="s1">'John'</span><span class="p">,</span> <span class="s1">'Lennon'</span><span class="p">);</span>
<span class="k">INSERT</span> <span class="k">INTO</span> <span class="n">myapp_person</span> <span class="p">(</span><span class="n">first_name</span><span class="p">,</span> <span class="n">last_name</span><span class="p">)</span> <span class="k">VALUES</span> <span class="p">(</span><span class="s1">'Paul'</span><span class="p">,</span> <span class="s1">'McCartney'</span><span class="p">);</span>
</pre></div>
</div>
<p>Each SQL file, if given, is expected to contain valid SQL statements
which will insert the desired data (e.g., properly-formatted
<tt class="docutils literal"><span class="pre">INSERT</span></tt> statements separated by semicolons).</p>
<p>The SQL files are read by the <a class="reference internal" href="../ref/django-admin.html#django-admin-sqlcustom"><tt class="xref std std-djadmin docutils literal"><span class="pre">sqlcustom</span></tt></a>, <a class="reference internal" href="../ref/django-admin.html#django-admin-sqlreset"><tt class="xref std std-djadmin docutils literal"><span class="pre">sqlreset</span></tt></a>,
<a class="reference internal" href="../ref/django-admin.html#django-admin-sqlall"><tt class="xref std std-djadmin docutils literal"><span class="pre">sqlall</span></tt></a> and <a class="reference internal" href="../ref/django-admin.html#django-admin-reset"><tt class="xref std std-djadmin docutils literal"><span class="pre">reset</span></tt></a> commands in <a class="reference internal" href="../ref/django-admin.html"><em>manage.py</em></a>. Refer to the <a class="reference internal" href="../ref/django-admin.html"><em>manage.py documentation</em></a> for more information.</p>
<p>Note that if you have multiple SQL data files, there's no guarantee of
the order in which they're executed. The only thing you can assume is
that, by the time your custom data files are executed, all the
database tables already will have been created.</p>
<div class="section" id="s-database-backend-specific-sql-data">
<span id="database-backend-specific-sql-data"></span><h3>Database-backend-specific SQL data<a class="headerlink" href="#database-backend-specific-sql-data" title="Permalink to this headline">¶</a></h3>
<p>There's also a hook for backend-specific SQL data. For example, you
can have separate initial-data files for PostgreSQL and MySQL. For
each app, Django looks for a file called
<tt class="docutils literal"><span class="pre"><appname>/sql/<modelname>.<backend>.sql</span></tt>, where <tt class="docutils literal"><span class="pre"><appname></span></tt> is
your app directory, <tt class="docutils literal"><span class="pre"><modelname></span></tt> is the model's name in lowercase
and <tt class="docutils literal"><span class="pre"><backend></span></tt> is the last part of the module name provided for the
<a class="reference internal" href="../ref/settings.html#std:setting-ENGINE"><tt class="xref std std-setting docutils literal"><span class="pre">ENGINE</span></tt></a> in your settings file (e.g., if you have defined a
database with an <a class="reference internal" href="../ref/settings.html#std:setting-ENGINE"><tt class="xref std std-setting docutils literal"><span class="pre">ENGINE</span></tt></a> value of
<tt class="docutils literal"><span class="pre">django.db.backends.postgresql</span></tt>, Django will look for
<tt class="docutils literal"><span class="pre"><appname>/sql/<modelname>.postgresql.sql</span></tt>).</p>
<p>Backend-specific SQL data is executed before non-backend-specific SQL
data. For example, if your app contains the files <tt class="docutils literal"><span class="pre">sql/person.sql</span></tt>
and <tt class="docutils literal"><span class="pre">sql/person.postgresql.sql</span></tt> and you're installing the app on
PostgreSQL, Django will execute the contents of
<tt class="docutils literal"><span class="pre">sql/person.postgresql.sql</span></tt> first, then <tt class="docutils literal"><span class="pre">sql/person.sql</span></tt>.</p>
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<h3><a href="../contents.html">Table Of Contents</a></h3>
<ul>
<li><a class="reference internal" href="#">Providing initial data for models</a><ul>
<li><a class="reference internal" href="#providing-initial-data-with-fixtures">Providing initial data with fixtures</a><ul>
<li><a class="reference internal" href="#automatically-loading-initial-data-fixtures">Automatically loading initial data fixtures</a></li>
</ul>
</li>
<li><a class="reference internal" href="#providing-initial-sql-data">Providing initial SQL data</a><ul>
<li><a class="reference internal" href="#database-backend-specific-sql-data">Database-backend-specific SQL data</a></li>
</ul>
</li>
</ul>
</li>
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