QSqlQuery not working

[BrainStorm]

I'm stucked at this problem since a very long time ( about one day or more ), I just can't find what's wrong! it looks so simple and until now everything in the project did work fine, relational tables, and etc, well, I isolated it in a function, may I explain first, I've loaded a QComboBox with a QSqlQueryModel with this query: "SELECT name FROM Categories", ok. Then I need to insert the id of the selected item in another table (for using as relation), I made this function:

int ProductsForm::categoryIdByName(const QString& name)
{
    QSqlQuery categories = QSqlQuery(model->database());
    categories.prepare("SELECT id FROM Categories "
               "WHERE name=:name)");
    categories.bindValue(":name",name);
    categories.exec();
    if(categories.size()==-1)
    {
    qDebug() << "error";
    return 1;
    }
    return cate

int ProductsForm::categoryIdByName(const QString& name)
{
    QSqlQuery categories = QSqlQuery(model->database());
    categories.prepare("SELECT id FROM Categories "
               "WHERE name=:name)");
    categories.bindValue(":name",name);
    categories.exec();
    if(categories.size()==-1)
    {
    qDebug() << "error";
    return 1;
    }
    return cate

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I call it with QComboBox::currentText(), BUT, as you see my concern there, query size aways return -1, no item! i've tried a lot of other querys, like "SELECT * FROM Categories", but nothing! I'm SURE the database, tables and items where created and inserted respectively, the program did work fine until this, I hope you guys can enlight-me and help me kick off this meaningless error. thanks in advance, sorry my bad english.

[saa7_go]

Try to identify the problem using QSqlQuery::lastError().

[BrainStorm]

Try to identify the problem using QSqlQuery::lastError().

it returns -1, no error =T

[saa7_go]

If you modify your codes to the following:

int ProductsForm::categoryIdByName(const QString& name)
{
    QSqlQuery categories(model->database());
    categories.exec(QString("SELECT id FROM Categories WHERE name='%1'").arg(name));
    if(categories.size()==-1)
    {
    qDebug() << "error";
    return 1;
    }
    .....
}

int ProductsForm::categoryIdByName(const QString& name)
{
    QSqlQuery categories(model->database());
    categories.exec(QString("SELECT id FROM Categories WHERE name='%1'").arg(name));
    if(categories.size()==-1)
    {
    qDebug() << "error";
    return 1;
    }
    .....
}

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is categories.size() value still -1 ?

[BrainStorm]

If you modify your codes to the following:

int ProductsForm::categoryIdByName(const QString& name)
{
    QSqlQuery categories(model->database());
    categories.exec(QString("SELECT id FROM Categories WHERE name='%1'").arg(name));
    if(categories.size()==-1)
    {
    qDebug() << "error";
    return 1;
    }
    .....
}

int ProductsForm::categoryIdByName(const QString& name)
{
    QSqlQuery categories(model->database());
    categories.exec(QString("SELECT id FROM Categories WHERE name='%1'").arg(name));
    if(categories.size()==-1)
    {
    qDebug() << "error";
    return 1;
    }
    .....
}

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is categories.size() value still -1 ?

yesss...

[BrainStorm]

int ProductsForm::categoryIdByName(const QString& name)
{
    QSqlQuery categories = QSqlQuery(model->database());
    categories.exec(QString("SELECT id FROM Categories WHERE name='%1'").arg(name));
    categories.first();
    return categories.value(0).toInt();

int ProductsForm::categoryIdByName(const QString& name)
{
    QSqlQuery categories = QSqlQuery(model->database());
    categories.exec(QString("SELECT id FROM Categories WHERE name='%1'").arg(name));
    categories.first();
    return categories.value(0).toInt();

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it works now, and i still don't know why! ^^" but thanks anyway

[saa7_go]

Are you using sqlite database? If you are using sqlite, it doesn't support reporting information about query sizes. So, this is why you always get -1.

[BrainStorm]

Are you using sqlite database? If you are using sqlite, it doesn't support reporting information about query sizes. So, this is why you always get -1.

yes, i'm using sqlite

[Lykurg]

yes, i'm using sqlite

then you can check via

QSqlQuery categories = QSqlQuery(model->database());
categories.prepare("SELECT id FROM Categories "
           "WHERE name=:name)");
categories.bindValue(":name",name);
categories.exec();
if (!categories.next())
{
  // error and return;
}
 
categories.value(0)/*...*/

QSqlQuery categories = QSqlQuery(model->database());
categories.prepare("SELECT id FROM Categories "
           "WHERE name=:name)");
categories.bindValue(":name",name);
categories.exec();
if (!categories.next())
{
  // error and return;
}

categories.value(0)/*...*/

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[Lesiok]

Is this code "copy and paste" ? If YES, You have an error in line 2. Signe ) after :name.

[BrainStorm]

then you can check via

QSqlQuery categories = QSqlQuery(model->database());
categories.prepare("SELECT id FROM Categories "
           "WHERE name=:name)");
categories.bindValue(":name",name);
categories.exec();
if (!categories.next())
{
  // error and return;
}
 
categories.value(0)/*...*/

QSqlQuery categories = QSqlQuery(model->database());
categories.prepare("SELECT id FROM Categories "
           "WHERE name=:name)");
categories.bindValue(":name",name);
categories.exec();
if (!categories.next())
{
  // error and return;
}

categories.value(0)/*...*/

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i see.. but i think using QSqlQuery::next(); once is the same as using QSqlQuery::first();

[BrainStorm]

By the way, does anyone knows how to create a button (flat would be nice) that drops a drop menu?

[Lykurg]

i see.. but i think using QSqlQuery::next(); once is the same as using QSqlQuery::first();

Yes, missed that, since in the code snippet the return was not checked if it is valid.

By the way, does anyone knows how to create a button (flat would be nice) that drops a drop menu?

Use a normal buttun and set a menu via QPushButton::setMenu(). for flat use QPushButton::setFlat().

[BrainStorm]

Use a normal buttun and set a menu via QPushButton::setMenu(). for flat use QPushButton::setFlat().

Ohh.. i see ^^ thanks, i was using QMenu::popup() with QPushButton::pos() :p