I found a solution by my self.
My solution ... :
show in the relation field only a ComboBox
(in future i will have a Lable to change the label by click to ComoBox)
can read and write the value of the current filed
So...at first i find out, that i used in the example above the Quick.Controls 1 .. so the old one.
Now i update my Code to Quick.Controls 2.
The only misstake i found is, i haven't read the api to the end.
Why was the resulting Column empty?
When you use realtions and one of the columnName of both tables are equal (in this example like 'name'), the filedName will change in the form of (e.g. tablename_columnname_id)
QSqlRelationTableModel - Found under 'Detail Description' under 'Notes'
When you debug the currentFieldNames u find the right name. In the example above the value use:
city_name_3
When you use a read-only Component like Label, it looks like:
Label {
text: city_name_3
}
When you want to use a read-write value in a comboBox, i found only the solution to write my one invokable funtion to get the relation-data: (this code is only for Test to get and write the Data .. it is not optimiesd for now)
QSqlRealtionTableModel:
[HEADER]
...
Q_INVOKABLE QVariant getRelation(const QModelIndex &item, int role = Qt::EditRole);
...
[CPP]
QVariant LQSqlRelationalTableModel::getRelation(const QModelIndex &item, int role)
{
if (item.row() >= rowCount())
return QString();
QSqlRelation rela = relation(role);
// is any realtion on this role?
if(!rela.isValid())
return QString();
// get the table of the realtion
QSqlTableModel *rModel = relationModel(role);
QVariantList list;
for(int i = 0; i < rModel->columnCount(); i++)
{
// look for the write headerName we need
if(rModel->headerData(i, Qt::Orientation::Horizontal) == rela.displayColumn())
{
for(int j = 0; j < rModel->rowCount(); j++)
{
// use the data-method for QSqlTableModel to get all values from the RealtionCoumn and save it in a List
QModelIndex modelIndex = rModel->index(j, i);
QVariant value = rModel->data(modelIndex);
list.append(value);
}
break;
}
}
return list;
}
When you use now this data for a model, you got a list of all the poibile relation-data:
[QML]
TableView{
model: relaModel
delegate: DelegateChooser { // Qt.Quick.Controls 2
DelegateChoice {
column: 0
delegate: Label { // it is also possible to use as spinbox, but by id you do not need realy
text: id
}
}
DelegateChoice {
column: 1
delegate: Label {
text: name
}
}
DelegateChoice {
column: 2
delegate: ComboBox {
implicitWidth: 140
onActivated: {
relaModel.setData(relaModel.index(row, column), currentText)
}
Component.onCompleted: {
model = relaModel.getRelation(relaModel.index(row, column))
currentIndex = relaModel.hasRelation(relaModel.index(row, column), city_name_3)
}
}
}
DelegateChoice {
column: 3
delegate: TextField {
text: country_name_2
selectByMouse: true
implicitWidth: 140
onAccepted: {
// i don't know why the get a different row like '-1' - so i have to check it
if (row >= 0) {
var sendText = text
relaModel.setData(relaModel.index(row, column), text)
}
}
}
}
}
}
so know it comes the importend thing:
in the comboBox the come the hole Data from the relationTable, so there text is the expected one.
in the TextField of Column 3 (Country) can you write the text by hand. But the Text have to be exactly one of the realtionData's-ID. So you do not have the ID -> you have the value, the Data will not write in the Database. -> you will handle this in ::setData(...)
Why does the cpp look so difficult and to much for some little thing?
currently i found this solution cause you got only the realtion-data but you have to set the right id 5000 .
Example: for the first Row you got for Espen the city-id: 5000 -> this is the realtion to city-name Oslo
The Problem is, that you get in the ::data-function the realtion-Data ('Oslo') and not the id ('5000')
When you wnat to set the data, you have to compare, if the data in the City-Table in Column Name. So you only handle the data with the realtion and not with the id.
-> that make it immpossible, that you use unique-values in the column name of the table city
Why?
When you have two values with same name, the data will fetch only the first one. so it is possible that you got the wrong data
So now my test looks like:
[image: a3bb8cbd-a33f-44fa-8c63-b8ae890d5ac1.jpg]
+++++++++++++++++++++++++
The next questions is, how to get the id (5000) instead of the realtion-Data (Oslo ) to handle columns with no unique-values. Any Idea?
+++++++++++++++++++++++++
I know i use in this example a SpinBox for Id, but it is only a test to handle some Components with this QSqlRealtionTableModel.
I'm realy sorry for my english, but i hope you understand all what i want to tell you.
Greetings from Germany
