ComboBoxDelegate taking data from MySQL database

Question

There are two tables: Warehouse and Ingredients, interconnected by a foreign key by id . Arranged ComboBoxDelegate in QTableView . ComboBox takes data from the Warehouse table in the Weight column. But there is such a moment that it displays the entire column completely, and I need each row to have a choice of "weight" for the corresponding ID. At the moment, the status of the code is as follows:

 ComboBoxDelegate::ComboBoxDelegate(QObject *parent) { DelegateModel = new QSqlQueryModel; DelegateModel->setQuery("SELECT weight FROM sklad, ingridient WHERE sklad.idsklad=ingridient.iding;"); } QWidget *ComboBoxDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &/* option */, const QModelIndex &/* index */) const { QComboBox *editor = new QComboBox(parent); editor->setModel(DelegateModel); return editor; }

Tell me who can do it, but already Moscow has broken how to do it.

alexis031182 alexis031182 5.966 one 9 44 · Accepted Answer · 2016-12-17T09:24:53

 QWidget *ComboBoxDelegate::createEditor(QWidget *parent , const QStyleOptionViewItem &option , const QModelIndex &index) const { // Индекс колонки с идентификаторами ингредиентов. const int iding_col = 0; const QVariant iding = index.model()->data(index.model() ->index(index.row(),iding_col)); if(iding.isValid() == false) return Q_NULLPTR; QSqlQuery query; query.prepare( "SELECT `weight` FROM `sklad`" \ " WHERE `idsklad` = :idsklad"); query.bindValue(":idsklad", iding); if(query.exec() == false) return Q_NULLPTR; QComboBox *editor = new QComboBox(parent); // QStyleOptionViewItem содержит множество полезных вещей // для построения корректно выглядящего виджета редактора. editor->setGeometry(option.rect); // Каждый раз при создании виджета редактора // должен создаваться и новый инстанс модели, // поскольку выборка данных различна для каждой из строк. // Установка же виджета редактора в качестве родителя модели // позволяет не заботиться о своевременном удалении последней. QSqlQueryModel *model = new QSqlQueryModel(editor); model->setQuery(query); editor->setModel(model); return editor; }

Let's say that I will get a unique key in the Warehouse table.
Is it possible to somehow get the key of the item that I chose in the ComboBox, so that later it was possible to edit the records through the ComboBox?
First, get the index of the selected element QComboBox , then from the model connected to it, by the column name, you get the value of the primary key of the record.
You can also use the QSqlRelation... classes QSqlRelation... , but they are not suitable for all cases.
I apologize for the stupid questions, with the delegates are not yet familiar)

Majestio Majestio 2,917 one five 32 · Answer 2 · 2016-12-17T07:46:28

Tell me who can do it, but the Mosk has already broken how to do it

It is necessary to edit the query:

 SELECT weight FROM sklad, ingridient WHERE sklad.idsklad=ingridient.iding AND ingridient.iding = число

A "number" is calculated by QModelIndex . I would dig this way.

Majestio

2,917 one five 32

Thank you, I will try - Leonty Kopytov
However ... I could be wrong, but you have a little wrong with business logic. "Available" - should not be editable, but should be computable, as the difference between the SUM () of the product in stock, and the SUM () used. Well this is IMHO, you know better there. - Majestio
The fact of the matter is that initially I had just cells with a sum, but when I clicked on the button, this sum should decrease, which means I need to write down the rest somewhere and then I had problems, so I decided to do ComboBox. In principle, this is only a manufacturing practice and most likely will not be used anywhere. - Leonty Kopytov

|

ComboBoxDelegate taking data from MySQL database

2 answers 2

More articles: