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POQt4 and MySQL5 - Binding QByteArray "1:1" as binary data
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copied!<p>I have some issues with character encoding of a binary value using Qt4 and MySQL5.</p> <p>Let's say we want to bind a value containing the four bytes <code>\xDE \xAD \xBE \xEF</code>. I check the bound value using the MySQL function <code>HEX()</code> using this code:</p> <pre><code>#include <QtGui/QApplication> #include <QDebug> #include <QSqlQuery> #include <QVariant> #include <QSqlRecord> int main(int argc, char *argv[]) { QApplication a(argc, argv); QSqlDatabase db = QSqlDatabase::addDatabase("QMYSQL"); if(!db.open("test", "test")) exit(1); QSqlQuery q("SELECT HEX(?)"); q.addBindValue(QVariant(QByteArray::fromHex("DEADBEEF"))); if(!q.exec()) exit(1); if(!q.next()) exit(1); qDebug() << q.record().value(0).toString(); return a.exec(); } </code></pre> <p>The output of this code is <code>"DEADEFBFBDEFBFBD"</code> which is obviously the HEX code of <code>\xDE \xAD \xBE \xEF</code> interpreted as a latin1-encoded string and then encoded as a UTF8 string.</p> <p>If I do not bind the value using addBindValue() but placing it directly into the query using <code>UNHEX('DEADBEEF')</code> results in the expected behaviour (which isn't surprising...).</p> <p>Where does the UTF8 encoding step take place?</p> <p>(Finally, I want to store a binary value "1:1" into a BLOB field.)</p> <p><strong>OS:</strong> Ubuntu 10.10 (32 bit)<br> <strong>Qt Version:</strong> 4.7.0 (Ubuntu package)<br> <strong>MySQL Version:</strong> 5.1.49-1ubuntu8.1</p> <p>Thanks in advance!</p>

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