Creating a database table in Qt

Article Metadata

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Tested with

Devices(s): Nokia 5800 eXpressMusic, Nokia N900

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Compatibility

Platform(s): Qt

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Article

Keywords: QSqlDatabase, QSQlite, QSqlError, QSqlQuery

Created: (09 Sep 2009)

Last edited: tepaa (11 Sep 2009)

Overview

This example shows you how to create 'person' table into (SQLite) database in Qt.

Table person has following columns

• id (integer primary key), this is autoincrement field http://www.sqlite.org/autoinc.html
• firstname (varchar(20))
• lastname (varchar(30))
• age (integer)

Preconditions

• Qt is installed on your platform

• • S60
    • Download Qt for S60 release from here: Qt for S60 pre-release
    • Install Qt for S60: Installing Qt on S60
    • Check this link for installation guide: How to install the package.
    • Qt for S60 Tower release has SQLite support. Needed libraries are bilt in the Qt release.

• • Maemo
    • More information about Qt on Maemo can be found here: Qt4 Maemo port

Maemo SQLite development needs following packages to be installed:

• libqt4-sql
• libqt4-sql-sqlit
• libsqlite3-0
• libsqlite3-dev

Header

#include <QObject>
#include <QSqlDatabase>
#include <QSqlError>
#include <QSqlQuery>
 
class DatabaseManager : public QObject
    {
    public:
        DatabaseManager(QObject *parent = 0);
        ~DatabaseManager();
 
    public:
        bool openDB();
        bool createPersonTable();
 
    private:
        QSqlDatabase db;
    };

Source

Create "person" table.

bool DatabaseManager::createPersonTable()
    {
    // Create table "person"
    bool ret = false;
    if (db.isOpen())
        {
        QSqlQuery query;
        ret = query.exec("create table person "
                  "(id integer primary key, "
                  "firstname varchar(20), "
                  "lastname varchar(30), "
                  "age integer)");
 
        }
    return ret;
    }

Rest of the code...

bool DatabaseManager::openDB()
    {
    // Find QSLite driver
    db = QSqlDatabase::addDatabase("QSQLITE");
 
    #ifdef Q_OS_LINUX
    // in Maemo we create database into memory because
    // it does not work from file
    db.setDatabaseName(":memory:");
    #else
    // Set database to be created into file. 
    // In Symbian file exists in the application private folder
    db.setDatabaseName("my.db.sqlite");
    #endif
 
    // Open databasee
    return db.open();
    }

Postconditions

Database table "person" created.

See also

• Tools:Creating SQLite database in Qt
• Tools:Creating database table in Qt
• Tools:Insert row into database in Qt
• Tools:Search data from the database in Qt
• Tools:Delete data from database in Qt
• Select data from database without using SQL statements in Qt
• Tools:Using QDataWidgetMapper for showing data from database in Qt

• w3schools.com/Sql
• QtSql module