QSqlRelationalTableModel produces useless Sql statement

[ObiWanKenobe]

Hi everybody,

I have a problem with the QSqlRelationalTableModel.
I have the following code:

patientModel = new QSqlRelationalTableModel(this, myDb);
    patientModel->setTable("PATIENTEN");
    patientModel->setRelation(patientModel->fieldIndex("ANGELEGTVON"), QSqlRelation("BENUTZER", "PK_ID", "KRZ")); /*created by*/
    patientModel->setRelation(patientModel->fieldIndex("GEAENDERTVON"), QSqlRelation("BENUTZER", "PK_ID", "KRZ"));/*changed by*/
    patientModel->setRelation(patientModel->fieldIndex("BEHANDLER"), QSqlRelation("BENUTZER", "PK_ID", "KRZ"));/*doctor*/
    patientModel->setEditStrategy(QSqlTableModel::OnManualSubmit);
    if (PatId > 0) 
        patientModel->setFilter(QString ("PATIENTEN.PK_ID = %1").arg(m_PatId));
    patientModel->select();

patientModel = new QSqlRelationalTableModel(this, myDb);
    patientModel->setTable("PATIENTEN");
    patientModel->setRelation(patientModel->fieldIndex("ANGELEGTVON"), QSqlRelation("BENUTZER", "PK_ID", "KRZ")); /*created by*/
    patientModel->setRelation(patientModel->fieldIndex("GEAENDERTVON"), QSqlRelation("BENUTZER", "PK_ID", "KRZ"));/*changed by*/
    patientModel->setRelation(patientModel->fieldIndex("BEHANDLER"), QSqlRelation("BENUTZER", "PK_ID", "KRZ"));/*doctor*/
    patientModel->setEditStrategy(QSqlTableModel::OnManualSubmit);
    if (PatId > 0) 
        patientModel->setFilter(QString ("PATIENTEN.PK_ID = %1").arg(m_PatId));
    patientModel->select();

To copy to clipboard, switch view to plain text mode 

When I call patientModel->select()then, QSqlRelationalTableModel produces the following Sql statement:

SELECT 
PATIENTEN."PK_ID", PATIENTEN."VORNAME", PATIENTEN."NACHNAME", ...
relTblAl_10.KRZ AS BENUTZER_KRZ_3, 
relTblAl_12.KRZ AS BENUTZER_KRZ_2, 
relTblAl_16.KRZ, ...
FROM 
PATIENTEN, BENUTZER relTblAl_10, BENUTZER relTblAl_12, BENUTZER relTblAl_16 
WHERE 
(PATIENTEN."BEHANDLER" = relTblAl_10.PK_ID AND 
PATIENTEN."GEAENDERTVON" = relTblAl_12.PK_ID AND 
PATIENTEN."ANGELEGTVON" = relTblAl_16.PK_ID) AND 
(PATIENTEN.PK_ID = 2678)

SELECT 
PATIENTEN."PK_ID", PATIENTEN."VORNAME", PATIENTEN."NACHNAME", ...
relTblAl_10.KRZ AS BENUTZER_KRZ_3, 
relTblAl_12.KRZ AS BENUTZER_KRZ_2, 
relTblAl_16.KRZ, ...
FROM 
PATIENTEN, BENUTZER relTblAl_10, BENUTZER relTblAl_12, BENUTZER relTblAl_16 
WHERE 
(PATIENTEN."BEHANDLER" = relTblAl_10.PK_ID AND 
PATIENTEN."GEAENDERTVON" = relTblAl_12.PK_ID AND 
PATIENTEN."ANGELEGTVON" = relTblAl_16.PK_ID) AND 
(PATIENTEN.PK_ID = 2678)

To copy to clipboard, switch view to plain text mode 

It seems correct, but it doesn't work most of the time, because "GEAENDERTVON" (e.g. "changed by") is most of the time NULL and the result set is empty.
The correct way would be a LEFT OUTER JOIN.

Is this a bug or am I missing something?

Thanks in advance.

[Lesiok]

This is not a bug and You don't missing something. QSqlRelationalTableModel is as is.

[ObiWanKenobe]

This is not a bug and You don't missing something. QSqlRelationalTableModel is as is.

Thanks for your reply, Lesiok.

If you ask me, it's a bug. Or at least there's a lack of implementation.
What is QSqlRelationalTableModel good for, if it can not handle NULL foreign keys.

Wouldn' you agree?

[Lesiok]

This is a lack of implementation. So we have our SqlRelationalModel.