SQLite returns result for sqlite_master but not for a user table ??????????
Hi all !
This is not a new problem but answers from different places never get me a workink solution ! So…
QT = 4.8.0
IDE = QT Creator with MINGW
OS = Windows XP (and I tried on Win 7 also and on Ubuntu !!!)
The problem :
I try to select some data in a table from a SQLite DB. If I tried to query the sqlite_master table, it does work ! However with user table named pkserial, it does not ? Why ????????
The project file is :
- #-------------------------------------------------
- #
- # Project created by QtCreator 2012-04-27T13:17:26
- #
- #-------------------------------------------------
- QT += core gui sql
- TARGET = TestMySQL
- TEMPLATE = app
- SOURCES += main.cpp\
- mainwindow.cpp
- HEADERS += mainwindow.h
- FORMS += mainwindow.ui
The code :
- void MainWindow::toolButtonClicked()
- {
- db.setDatabaseName(dbFile);
- if (!db.open())
- {
- qDebug() << "unable to open db :" << db.lastError().text();
- return;
- }
- qDebug() << "tables :" << db.tables();
- // Query 1
- // Query 2
- // QString sql = QLatin1String("SELECT name FROM sqlite_master WHERE type='table' OR type='view' "
- // "UNION ALL SELECT name FROM sqlite_temp_master WHERE type='table' OR type='view'");
- if (query.exec(sql))
- {
- while(query.next())
- qDebug() << query.value(0).toString();
- } else
- qDebug() << "error :" << query.lastError().text();
- qDebug() << "End of test";
- }
When the code is executed, the result is :
- Starting C:\...\TestMySQL-build-desktop-Qt_Commercial_4_8_0_for_Desktop__MinGW__Debug\debug\TestMySQL.exe...
- drivers : ("QSQLITE", "QODBC3", "QODBC")
- "C:/Documents and Settings/Jack/My Documents/assmehari2010-v1a" true
- tables : ("pkserial")
- End of test
- C:\...\TestMySQL-build-desktop-Qt_Commercial_4_8_0_for_Desktop__MinGW__Debug\debug\TestMySQL.exe exited with code 0
If I comment query 1 and uncomment query 2, the result is :
- Starting C:\...\TestMySQL-build-desktop-Qt_Commercial_4_8_0_for_Desktop__MinGW__Debug\debug\TestMySQL.exe...
- drivers : ("QSQLITE", "QODBC3", "QODBC")
- "C:/Documents and Settings/Jack/My Documents/assmehari2010-v1a" true
- tables : ("pkserial")
- "pkserial"
- End of test
- C:\...\TestMySQL-build-desktop-Qt_Commercial_4_8_0_for_Desktop__MinGW__Debug\debug\TestMySQL.exe exited with code 0
You can see that line 5 shows the name of the table that was retrieved by the sql query 2 !
Therefore, whenever I query the catalog table, it works and when I query a user table, it does not ???????
Does anyone have a clue on what is happening ?
Thank you !
3 replies
Hi ! Thank you for your reply ! Before beginning this thread, I did tested that case and I insure that the table pkserial was not empty !
Here is the content of that table as seen in SQLite Maestro:
- tableName lastSerial fkProject
- GClassif 389 1
- GCodes 4953 1
- GExpo 3016 1
- GGravite 16 1
- GGroupeTypeActif 30 1
- GProcessus 0 1
- GProcessusTypeActif 0 1
- GProject 3 1
- GQuestions 2905 1
This table has three columns : tableName, lastSerial and fkProject. The first row gives the title and roow 2 up to the end gives each record.
So the problem remain unresolved !
Thank you to continue searching for a solution !
Solved !
The database used to save the data has been build using SQL Maestro. In that case, the data inserted in the table is not returned when a Select is done on the table.
If I used SQLite Expert to create the database, everything works fine, that is, the data can be selected and is accessed through the query in my Qt Application.
Concluison : The tool used to create the database is the cause of the problem ! This means that you must take care of what tool you use to create the database. Moreover, I found that if I create (using my Qt application) a table X in a database Z created with SQL Maestro, than the data for that table X is returned as expected. But the other tables within that database Z are not !!!!!!!!!
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