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<div class="title">Database models </div> </div>
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<div class="textblock"><p>Database models are usually created by subclassing the <a class="el" href="classQDjangoModel.html" title="The QDjangoModel class is the base class for all models.">QDjangoModel</a> class.</p>
<p>The following example defines a <code>User</code> model suitable for storing basic account information, and illustrate different types of queries on this model.</p>
<h2><a class="anchor" id="declaring"></a>
Declaring your model</h2>
<p>To declare your model, subclass the <a class="el" href="classQDjangoModel.html" title="The QDjangoModel class is the base class for all models.">QDjangoModel</a> class, and define a property using the <a href="http://doc.qt.nokia.com/latest/qobject.html#Q_PROPERTY">Q_PROPERTY</a> macro for each database field. You can provide additional information about a field using the <a href="http://doc.qt.nokia.com/latest/qobject.html#Q_CLASSINFO">Q_CLASSINFO</a> macro:</p>
<ul>
<li><code>max_length</code> : the maximum length of the field (used when creating the database table) </li>
<li><code>primary_key</code> : if set to 'true', this field will be used as the primary key. If no primary key is explicitly defined, an auto-increment integer field will be added.</li>
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<div class="fragment"><pre class="fragment"><span class="preprocessor">#include "QDjangoModel.h"</span>
<span class="keyword">class </span>User : <span class="keyword">public</span> <a class="code" href="classQDjangoModel.html" title="The QDjangoModel class is the base class for all models.">QDjangoModel</a>
{
Q_OBJECT
Q_PROPERTY(QString username READ username WRITE setUsername)
Q_PROPERTY(QString password READ password WRITE setPassword)
Q_CLASSINFO(<span class="stringliteral">"username"</span>, <span class="stringliteral">"max_length=255"</span>)
Q_CLASSINFO("password", "max_length=128")
public:
QString username() const;
<span class="keywordtype">void</span> setUsername(const QString &username);
QString password() const;
<span class="keywordtype">void</span> setPassword(const QString &password);
private:
QString m_username;
QString m_password;
};
</pre></div><h2><a class="anchor" id="implementing"></a>
Implementing your model</h2>
<div class="fragment"><pre class="fragment">QString User::username()<span class="keyword"> const</span>
<span class="keyword"></span>{
<span class="keywordflow">return</span> m_username;
}
<span class="keywordtype">void</span> User::setUsername(<span class="keyword">const</span> QString &username)
{
m_username = username;
}
QString User::password()<span class="keyword"> const</span>
<span class="keyword"></span>{
<span class="keywordflow">return</span> m_password;
}
<span class="keywordtype">void</span> User::setPassword(<span class="keyword">const</span> QString &password)
{
m_password = password;
}
</pre></div><h2><a class="anchor" id="registering"></a>
Registering and using your model</h2>
<p>To make your model available for database operations, you should now register your model using:</p>
<div class="fragment"><pre class="fragment">QDjango::registerModel<User>();
</pre></div><p>Once you have set the database (see <a class="el" href="database.html">Database configuration</a>), you will now be able to create model instances and save them to the database:</p>
<div class="fragment"><pre class="fragment">User *user = <span class="keyword">new</span> User;
user->setUsername(<span class="stringliteral">"someuser"</span>);
user->setPassword(<span class="stringliteral">"somepassword"</span>);
user->save();
</pre></div><p>.. or remove them from the database:</p>
<div class="fragment"><pre class="fragment">user->remove();
</pre></div><p>You can also perform operations such as filtering or retrieving model instances as described in <a class="el" href="queries.html">Making queries</a>.</p>
<h2><a class="anchor" id="qobject"></a>
Using QDjango without QDjangoModel</h2>
<p>Although it is recommended you make your models inherit <a class="el" href="classQDjangoModel.html" title="The QDjangoModel class is the base class for all models.">QDjangoModel</a>, it is not strictly necessary. <a class="el" href="classQDjango.html" title="The QDjango class provides a set of static functions.">QDjango</a> can in fact handle any QObject-derived class, but you will lose some of the syntactic sugar.</p>
<p>If for instance you defined a <code>SomeObject</code> class which inherits <a href="http://doc.qt.nokia.com/latest/qobject.html">QObject</a>, you can write:</p>
<div class="fragment"><pre class="fragment"><a class="code" href="classQDjangoMetaModel.html" title="The QDjangoMetaModel class holds the database schema for a model.">QDjangoMetaModel</a> meta = QDjango::registerModel<SomeObject>();
<span class="comment">// prepare a SomeObject instance</span>
SomeObject *obj = <span class="keyword">new</span> SomeObject;
obj->setSomeProperty(<span class="stringliteral">"some value"</span>);
obj->setOtherProperty(<span class="stringliteral">"other value"</span>);
<span class="comment">// save the object</span>
meta.<a class="code" href="classQDjangoMetaModel.html#a6837d4f7f1d89327516e2e9ad39bef32" title="Saves the given model instance to the database.">save</a>(obj);
<span class="comment">// remove the object from database</span>
meta.<a class="code" href="classQDjangoMetaModel.html#a3b0a36043675008e7114b420a73e3f62" title="Removes the given model instance from the database.">remove</a>(obj);
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