Hi, I tried it and unfortunately it does nos compile...
Qt Code: 
  1. #include "phonebook.h"
  2. #include "ui_phonebook.h"
  3. #include <QMessageBox>
  4. #include <QDesktopservices.h>
  5. //./phonebook.db
  6. PhoneBook::PhoneBook(QWidget *parent) :
  7.     QWidget(parent),
  8.     ui(new Ui::PhoneBook)
  9. {
  10.     ui->setupUi(this);
  11.  
  12.     database = new QSqlDatabase();
  13.  
  14.     //set database driver to QSQLITE
  15.     *database = QSqlDatabase::addDatabase("QSQLITE");
  16.    // database->setDatabaseName(":memory:");
  17.     //database->setDatabaseName("./phonebook.db");
  18.     QString dbName = QDesktopServices::storageLocation (QDesktopServices::DataLocation) + "/phonebook.db";
  19.     database->setDatabaseName(dbName);
  20.  
  21.     //can be removed
  22.     //database->setHostName("localhost");
  23.     //database->setUserName("");
  24.     //database->setPassword("");
  25.  
  26.     if(!database->open())  {
  27.         QMessageBox::warning(0,"Error",tr("Couldn't open database file: %1").arg(database->lastError().text()));
  28.     }
  29.  
  30.      QSqlQuery query;
  31.      query.exec("CREATE TABLE IF NOT EXISTS Contacts (id int primary key, "
  32.                 "name varchar(20), mobile varchar(20),city varchar(20))");
  33.     all_model = new QSqlTableModel(this, *database);
  34.     updateTable();
  35.  
  36.     search_model = new QSqlTableModel(this, *database);
  37.     search_model->setTable("Contacts");
  38. }
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But if I comment this line like this..
Qt Code: 
  1. if(!database->open())  {
  2.         QMessageBox::warning(0,"Error",tr("Couldn't open database file: %1"));//.arg(database->lastError().text()));
  3.     }
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and here is the result when compiled...
Qt Code: 
  1. Executable file: 15482 2011-06-13T15:12:58 C:\QtSDK\Symbian\SDKs\Symbian1Qt473\\epoc32\release\gcce\urel\SQLite_example.exe
  2. Starting application...
  3. Application running with pid 4355.
  4. [Qt Message] QSqlQuery::exec: database not open
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thanks,
lam-ang