2019-06-20 03:56:39 +00:00
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= Qt: обмен бинарными данными с БД
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:title-separator: {sp}|
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:category: Программирование
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:tags: программирование, qt, postgresql, бд
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Таблица, с которой осуществляется обмен:
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[source,sql]
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----
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CREATE TABLE example (
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id INTEGER,
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bin_data BYTEA
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);
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----
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Запись данных:
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[source,cpp]
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----
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const char cart[] = {0x04, 0x43, 0x00, 0x9A};
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QByteArray binDataArray(QByteArray::fromRawData(cart, 4));
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QSqlField dataField("bin_data", QVariant::ByteArray);
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byteField.setValue(binDataArray);
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QSqlDatabase db = QSqlDatabase::database();
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QSqlQuery query;
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query.exec(QString("INSERT INTO files VALUES(%1, %2);")
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.arg(18)
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.arg(db.driver()->formatValue(dataField)));
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2019-07-15 18:47:09 +00:00
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----
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2019-06-20 03:56:39 +00:00
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Чтение данных:
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[source,cpp]
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2019-07-15 18:47:09 +00:00
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----
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2019-06-20 03:56:39 +00:00
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QSqlQuery query;
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query.exec("SELECT id, bin_data FROM example LIMIT 1");
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query.next();
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QByteArray binDataArray = query.value(query.record().indexOf("bin_data")).toByteArray();
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2019-07-15 18:47:09 +00:00
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----
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2019-06-20 03:56:39 +00:00
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