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POUsing Qt Database in Large Application
 

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    <p>I have a question regarding using Databases in Qt.</p> <p>In other languages I would do something like create a database in the main class and pass a pointer of this database to other classes to use.</p> <p>I have been playing around in Qt and it seems that if I initialize a database in the main class then I can just write and execute a query in any other class and it will use this database and I am a bit confused because there seems to be no reference to a database.</p> <p>Could someone explain this for me :)</p> <p>Here is the Database class which is instanced in MainWindow.cpp</p> <pre><code>#include "database.h" Database::Database() { Connect(); } void Database::Connect() { db = QSqlDatabase::addDatabase("QSQLITE"); db.setDatabaseName("mydatabase­.dat"); if(db.open()){ qDebug() &lt;&lt; "Connected"; } else { qDebug() &lt;&lt; "Not Connected"; } } bool Database::SetupTables() { QSqlQuery qry; qry.exec("CREATE TABLE patients ( patient_id INT, firstname VARCHAR(100), lastname VARCHAR(100) ); "); return true; } </code></pre> <p>Here is a Window (Widget) i created called PatientList </p> <pre><code>#include "patientlist.h" #include "ui_patientlist.h" #include "database.h" #include &lt;QtSql&gt; #include &lt;QtDebug&gt; PatientList::PatientList(QWidget *parent) : QWidget(parent), ui(new Ui::PatientList) { ui-&gt;setupUi(this); QSqlQuery qry; if(qry.exec("SELECT patient_id,firstname,lastname FROM patients")){ qDebug() &lt;&lt; "Success"; } else { qDebug() &lt;&lt; "Error"; } } PatientList::~PatientList() { delete ui; } </code></pre> <p>This all works fine but I just feel like im doing something wrong because I have not mentioned the database created in the MainWindow.cpp</p>
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