QSqlRelationTableModel - how to obtain foreign key value

[Lesiok]

I have QSqlRelationTableModel and need to get foreign key value fo record not the value from related table. Is this possible with Qt classes ?

[yuriry]

This method may help you:

QSqlTableModel * QSqlRelationalTableModel::relationModel ( int column ) const

QSqlTableModel * QSqlRelationalTableModel::relationModel ( int column ) const

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[Lesiok]

This method may help you:

QSqlTableModel * QSqlRelationalTableModel::relationModel ( int column ) const

QSqlTableModel * QSqlRelationalTableModel::relationModel ( int column ) const

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I know this method but how can I obtain correct record from this model ?

[yuriry]

After getting a related model you can obtain an index using QAbstractItemModel::index and data using QAbstractItemModel::data. I hope the row number is the same as in the original model.

[Lesiok]

After getting a related model you can obtain an index using QAbstractItemModel::index and data using QAbstractItemModel::data. I hope the row number is the same as in the original model.

Unfortunately no. QSqlRelationalTableModel::relationModel represents related table in database and it have number of rows equel to number of records in this table.
I think that this is not trivial problem because SELECT statement constructed in QSqlRelationalTableModel::selectStatement method remove all columns which are foreign keys to another tables.
In example.
Main table people with columns name, surname, town_id.
Related table towns with columns name, id.

After :

QSqlRelationalTableModel model( parent, db);
model.setTable("people");
model.setRelation( 2,QSqlRelation("town", "id","name") );

QSqlRelationalTableModel model( parent, db);
model.setTable("people");
model.setRelation( 2,QSqlRelation("town", "id","name") );

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SELECT statement looks like :

SELECT "people"."name","people"."surname","relTblAl_3"."name" FROM "people","towns" "relTblAl_3" WHERE ("people"."town_id"="relTblAl_3"."id")  ORDER BY "people"."name" ASC

SELECT "people"."name","people"."surname","relTblAl_3"."name" FROM "people","towns" "relTblAl_3" WHERE ("people"."town_id"="relTblAl_3"."id")  ORDER BY "people"."name" ASC

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[yuriry]

Yeah, you are right, it might not be possible to get foreign key (unless the display column is also unique so that you can search the related model, but this is not a very good option). Frankly, I do not even use standard models while working with databases, only custom ones sub-classed from QAbstractItemModel...