I can't Insert a new data to SQLITE
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I tried to insert new data to the database. here's my code:
@#include "mainwindow.h"
#include <QtSql/QSqlDatabase>
#include <QtDebug>
#include <QtGui/QApplication>
#include <QtSql>int main(int argc, char *argv[])
{
QApplication app(argc, argv);//MainWindow mainWindow; //mainWindow.setOrientation(MainWindow::ScreenOrientationAuto); //mainWindow.showExpanded(); QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE"); db.setDatabaseName("C:\sqlite3\sample1.db"); if(!db.open()) { qFatal("Failed to connect!"); } else qDebug("Connected."); QSqlQuery qry; qry.prepare("insert into sample1.db (firstname, lastname) values ('John','Dean')"); if (!qry.exec()) qDebug() << qry.lastError(); else qDebug("Inserted"); db.close(); return 0; return app.exec();}
@It has no errors but when I look into my sqlite using SELECT statement to see if it works, nothings happened the data that I want to add is not there.
thanks in advance!
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Hi,
You should create table in the database and then to insert values into the table. Test your queries with SQlite command line tool such as sqlite3.exe before adding them to the source code.
Cheers,
Leon -
I think your database name is invalid. Remember, a backslash is used for escaping in C++ strings... It is good practice to only use backslashes for the display of paths on platforms where a backslash is the path separator (you do that translation using QDir::toNativeSeparators). In your own code, use forward slashes only.
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Hi again,
I just want to post several useful links which will solve the issue:
"CREATE TABLE":http://www.sqlite.org/lang_createtable.html
Examples:
"Creating an SQLite database in Qt":http://wiki.forum.nokia.com/index.php/CS001504_-Creating_an_SQLite_database_in_Qt
"Creating a database table in Qt":http://wiki.forum.nokia.com/index.php/CS001505-Creating_a_database_table_in_Qt
"Inserting a row into a database in Qt":http://wiki.forum.nokia.com/index.php/CS001506-_Inserting_a_row_into_a_database_in_QtFollow the examples in the order I have posted them, merge them into a single application and you will solve the issues.
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thanks to both of you! now I modified the code. but still nothing happened.
here's the code:
@#include "mainwindow.h"
#include <QtSql/QSqlDatabase>
#include <QtDebug>
#include <QtGui/QApplication>
#include <QtSql>int main(int argc, char *argv[])
{
QApplication app(argc, argv);//MainWindow mainWindow; //mainWindow.setOrientation(MainWindow::ScreenOrientationAuto); //mainWindow.showExpanded(); QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE"); db.setDatabaseName("C:/sqlite3/sample1.db"); if(!db.open()) { qFatal("Failed to connect!"); } else qDebug("Connected."); QSqlQuery qry; qry.prepare( "CREATE TABLE IF NOT EXISTS names (id INTEGER UNIQUE PRIMARY KEY, firstname VARCHAR(30), lastname VARCHAR(30))" ); if( !qry.exec() ) qDebug() << qry.lastError(); else qDebug() << "Table created!"; qry.prepare("insert into names (id, firstname, lastname) values (1, 'John','Dean')"); if (!qry.exec()) qDebug() << qry.lastError(); else qDebug("Inserted"); db.close(); return 0; return app.exec();}
@is there something in the code that i have to replace?
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[quote author="wenks21" date="1305614955"]is there something in the code that i have to replace?[/quote]
Have you tested your SQL statements only using the command line tool? Are they OK?
Best regards,
Leon -
[quote author="wenks21" date="1305615786"]It only connects to the database.[/quote]
So... after the "Connected." output, you get nothing else? Your code suggests that you should either get an error or an OK for both the queries you try to execute. If you get an error, please show it.Edit:
I think you are messing up the constructors of your QSqlQuery object. Try to use the constructor that takes a QSqlDatabase argument. -
You might try the QSqlQuery documentation to learn about the different constructors for that class...
If you get no other output, you might try to set a breakpoint at the place where you last get output, and follow the program execution statement by statement by running in debug mode (F5 in Qt Creator).
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Hi wenks21,
Did you resolve your problem?
I am in the same point... :( -
You need to open the actual file before opening the database within, like so....
@
QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
QFile newdbfile(QDir::toNativeSeparators(QDir::homePath()+"/test.sqlt"));
db.setDatabaseName(newdbfile.fileName());if (newdbfile.open(QIODevice::ReadWrite)) { if(!db.open()) { qFatal("Failed to connect!"); } else qDebug("Connected."); }@
notice, that I wrapped your db.open() with a newdbfile.open().
also, this little dance I did sure makes it easy to move around 'tween machines and platforms
@QFile newdbfile(QDir::toNativeSeparators(QDir::homePath()+"/test.sqlt")); db.setDatabaseName(newdbfile.fileName());@
I built and ran this code inserted into your code. It works.
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[quote author="solareclectic" date="1309313429"]You need to open the actual file before opening the database within, like so....[/quote]
You do not need to open the file. If the code above does not work it is most likely that you
- have no permission to write to the C:/sqlite3 directory
- have no directory C:/sqlite3, which prevents the QSQLITE driver from creating the file (this might be the reason why opening - and thus creating - the file solves your problem)
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Hi,
I have the same error with solareclectic code, The db is created and after 'Connected' output I don't get nothing, the table is not created.
Yes, I added QT += sql in my .pro file.
There is something I omitted because I didn't give importance and it is that I use QSQLITE2 driver instead of QSQLITE, could this be the error?
Thanks!