Showing GUID keys in Standart View Classes

[Rus]

Hello. Sorry for my pure English (i'm from Russia)

I want to use standart (QSqlQueryModel+QtableView) for working with MSSQL database.
When i trying to get MSSQL "uniqueidentifier" fileds from database, in View it shows as no-readable symbols.
I know that GUID supports in QT as UUid Class. But it not encluded in QVariant::type enum.

I can solve this problem, with subclassing a QSqlQueryModel and reimlplementing a data() - method. But I think that not only me face with this problem. Thank You.

[wysota]

Could you show us your code used for querying the database?

[Rus]

This is standart code; In database cdoc field is UNIQUEIDENTIFIER.

#include <QApplication>
#include <QSqlQuery>
#include <QVariant>
#include "MainWidget.h"
#include "iostream"
 
QSqlDatabase openconnnection(){
	QSqlDatabase db = QSqlDatabase::addDatabase("QODBC");
	db.setDatabaseName( "DRIVER={SQL Server};Server=DELTA;Database=Test;Trusted_Connection=yes;");
	db.open();
	return db;
};
///////////////////////////////// ** ////////////////////////////////////
int main(int argc, char *argv[]){
    QApplication app(argc, argv);       
    QSqlDatabase db = openconnnection();
    QSqlQuery sql("SELECT TOP 1 CDOC, DOCDATE FROM DOCS");    
    sql.first();
 
    const char* strCDOC = sql.value(0).toString().toLocal8Bit();
    std::cout << strCDOC << std::endl;
 
    const char* strDATE = sql.value(1).toString().toLocal8Bit();
    std::cout << strDATE << std::endl;      
    return app.exec();
}

#include <QApplication>
#include <QSqlQuery>
#include <QVariant>
#include "MainWidget.h"
#include "iostream"

QSqlDatabase openconnnection(){
	QSqlDatabase db = QSqlDatabase::addDatabase("QODBC");
	db.setDatabaseName( "DRIVER={SQL Server};Server=DELTA;Database=Test;Trusted_Connection=yes;");
	db.open();
	return db;
};
///////////////////////////////// ** ////////////////////////////////////
int main(int argc, char *argv[]){
    QApplication app(argc, argv);       
    QSqlDatabase db = openconnnection();
    QSqlQuery sql("SELECT TOP 1 CDOC, DOCDATE FROM DOCS");    
    sql.first();

    const char* strCDOC = sql.value(0).toString().toLocal8Bit();
    std::cout << strCDOC << std::endl;
    
    const char* strDATE = sql.value(1).toString().toLocal8Bit();
    std::cout << strDATE << std::endl;      
    return app.exec();
}

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Yesterday, i trying to get field as ByteArray. If I divide standart byte to 2 part 4-bit array in each. Each of new 4bit symbol - are the real symbol of UNIQUEIDENTIFIER.

[wysota]

Ouch... your code is bad... it's even Bad. First of all you shoould check if the query returned any result at all using QSqlQuery::next() or QSqlQuery::first() (check the return value). Second of all, you musn't store the value returned by toLocal8Bit() (which by the way returns a byte array not a const char*), because the byte array is a temporary object. You're just asking for your application to crash or work incorrectly.

[Rus]

No, it is not use-able code. It may be very bad. It code only shows that I can't show first field in query. I trying write smallest code for you.

[mazurekwrc]

check first what return db.open() and sql.first()

[Rus]

I sure that you don't understand my problem..
If i use qsqlquerymodel - it will be more simple to understand

#include <QApplication>
#include <QSqlQueryModel>
#include <QTableView>
#include "MainWidget.h"
#include "iostream"
 
QSqlDatabase openconnnection(){
	QSqlDatabase db = QSqlDatabase::addDatabase("QODBC");
	db.setDatabaseName( "DRIVER={SQL Server};Server=DELTA;Database=Test;Trusted_Connection=yes;");
	db.open();
	return db;
};
 
///////////////////////////////// ** ////////////////////////////////////
int main(int argc, char *argv[]){
    QApplication app(argc, argv);       
    QSqlDatabase db = openconnnection();
    QSqlQueryModel sqlmodel;    
    sqlmodel.setQuery("SELECT TOP 10 CDOC, DOCDATE FROM DOCS"); 
    QTableView tbl;
    tbl.setModel(&sqlmodel);
    tbl.show();
    return app.exec();
}

#include <QApplication>
#include <QSqlQueryModel>
#include <QTableView>
#include "MainWidget.h"
#include "iostream"

QSqlDatabase openconnnection(){
	QSqlDatabase db = QSqlDatabase::addDatabase("QODBC");
	db.setDatabaseName( "DRIVER={SQL Server};Server=DELTA;Database=Test;Trusted_Connection=yes;");
	db.open();
	return db;
};

///////////////////////////////// ** ////////////////////////////////////
int main(int argc, char *argv[]){
    QApplication app(argc, argv);       
    QSqlDatabase db = openconnnection();
    QSqlQueryModel sqlmodel;    
    sqlmodel.setQuery("SELECT TOP 10 CDOC, DOCDATE FROM DOCS"); 
    QTableView tbl;
    tbl.setModel(&sqlmodel);
    tbl.show();
    return app.exec();
}

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Problem step-by-step description:
In my database DOCS table contains more than 3 millions records. Than I started application, I see 10 records in grid, row's first columns is no-readable, second presents a standart date field.

wnd.jpg

How to present row's first column, like that: {4FEE5BC6-8904-45EC-B830-0000433322D2}

[wysota]

The data is probably returned as a byte array which you need to decode into string manually.