Import .csv file to sqlite3 database table on QT gui

问题

I am writing a QT GUI application that will import a .csv file to a sqlite database table my .csv file is in the path /home/aj/import_table.csv and my database is in /home/aj/testdatabase.db

i wrote the below code block---

void MainWindow::on_importButton_clicked()
{
    QSqlDatabase db=QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName("/home/aj/testdatabase.db");

    QString querystr;
    querystr=QString(".separator ","");
    QSqlQuery query(querystr,db);
    if(query.exec())
    {
        qDebug()<<"SUCCESSFULLY QUEIRED ";

        QString querystr2;
        querystr=QString(".import import_table.csv test_table");
    }
    else
    {
        qDebug()<<"ERROR DURING QUERY "<<db.lastError().text();
    }
}

but it is throwing error at compile time--

/home/aj/sqlite3test/mainwindow.cpp:34: error: invalid conversion from ‘const char*’ to ‘int’ [-fpermissive]
/home/aj/sqlite3test/mainwindow.cpp:34: error: conversion from ‘const char [1]’ to ‘QChar’ is ambiguous
/home/aj/sqlite3test/mainwindow.cpp:34: error: conversion from ‘const char [1]’ to ‘QChar’ is ambiguous
/usr/local/Trolltech/Qt-4.8.4/include/QtCore/qstring.h:90: error: initializing argument 1 of ‘QString::QString(int, QChar)’ [-fpermissive]

any solutions ???

is it happening because .separator and .import are sqlite terminal command and cannot be executed via the querystr=Qstring("... ... ..."); format ???

回答1:

This line:

querystr=QString(".separator ","");

is trying to construct a QString using two const char * as arguments to the constructor. According to the documentation there is no constructor that accepts this combination.

I think you meant to include the (") quotes inside the string. You need to escape them with backslashes, like this:

querystr=QString(".separator \",\"");

so that the compiler knows that they should be part of the string, rather than delimiting it.

That should fix your compilation error, HOWEVER your last comment is correct, the SQLite documentation states:

And, of course, it is important to remember that the dot-commands are interpreted by the sqlite3.exe command-line program, not by SQLite itself. So none of the dot-commands will work as an argument to SQLite interfaces like sqlite3_prepare() or sqlite3_exec().

In other words, if you want to read in a CSV file from a C++ program you have written yourself, you will have to parse the file in your own code and insert the records via SQL INSERT commands.

来源：https://stackoverflow.com/questions/27351546/import-csv-file-to-sqlite3-database-table-on-qt-gui

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c++

sqlite

qt4