CODEWITHSUNDEEP
sqlqtrelational
mike
mike

Reputation: 51

qt qsql relation is valid, but breaking table view

I am working with a QSqlRelationalTableModel, and have for the most part foreign key ids resolving to their name values via QsqlRelation quite happily:

QSqlRelationalTableModel *model = db->get_db_model();
model->setEditStrategy(QSqlTableModel::OnFieldChange);
model->setTable("materialproperty");
model->select();
model->setRelation(1, QSqlRelation("parameter", "id", "name"));


MyTableview->setModel(model);

works fine. But one particular relation:

model->setRelation(2, QSqlRelation("other", "id", "name"));

is causing the whole model to fail. The only difference between these two situations is that column 1 in table materialproperty is always populated, whereas 2 is often NULL. Is there a workaround for this behaviour, or another explanation? My ID fields are always text uuids. Btw If I construct a QSqlRelation and test it's validity, it passes ok.

Upvotes: 1

Views: 1052

Answers (2)

Ahmad Algohary
Ahmad Algohary

Reputation: 11

It works if you set the Left Join like this:

m_pModel->setJoinMode(QSqlRelationalTableModel::LeftJoin);

Upvotes: 1

typbl4
typbl4

Reputation: 141

By default QString QSqlTableModel::selectStatement() returns something like that:

  SELECT ...
    FROM table1 t1, table2 t2
    WHERE (t1.fk = t2.id) AND (<filter stuff>)
ORDER BY <something>

Try to reimplement it to return something like that:

SELECT ...
 FROM table1 t1 LEFT JOIN table2 t2 ON t1.fk = t2.id 
 WHERE <filter stuff>
 ORDER BY <something>

Upvotes: 1

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