DOCS.H

class Docs : public QObject
{
    Q_OBJECT

    Q_PROPERTY(int id READ getId WRITE setId NOTIFY idChanged)
    Q_PROPERTY(QString nome READ getNome WRITE setNome NOTIFY nomeChanged)
    Q_PROPERTY(QString html READ getHtml WRITE setHtml NOTIFY htmlChanged)

public:
    explicit Docs(QObject *parent = 0);
    explicit Docs(int id, QString nome, QString html, QObject *parent = 0);

    int getId() const;
    void setId(int value);

    QString getNome() const;
    void setNome(const QString &value);

    QString getHtml() const;
    void setHtml(const QString &value);

signals:
    void idChanged();
    void nomeChanged();
    void htmlChanged();

private:
    int id;
    QString nome;
    QString html;
};

DATABASE.H

#include "docs.h"

class Database : public QObject
{
    Q_OBJECT
public:
    explicit Database(QObject *parent = 0);
    Q_INVOKABLE QVariant getAll();

private:
    QSqlDatabase db;
};

DATABASE.CPP

QVariant Database::getAll()
{
    QList<Docs*> docs;
    if (db.open()) {
        QSqlQuery qry("SELECT * FROM docs;");
        if (!qry.lastError().isValid()) {
            while (qry.next()) {
                docs.append(new Docs(qry.value(0).toInt(),
                                     qry.value(1).toString(),
                                     qry.value(2).toString()));
            }
        } else {
            qDebug() << qry.lastError().text();
        }

    } else {
        qDebug() << db.lastError().text();
    }

    return QVariant::fromValue(docs);
}

MAIN.CPP

#include "database.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    Database db;

    QQmlApplicationEngine engine;
    engine.rootContext()->setContextProperty("docsDb", &db);
    engine.load(QUrl(QStringLiteral("qrc:/Main.qml")));

    return app.exec();
}