Example QCompleter with QSqlTableModel

all.csv

CompleterWithQSqlTableModel.pro

#-------------------------------------------------
#
# Project created by QtCreator 2017-09-17T11:02:01
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets sql

TARGET = CompleterWithQSqlTableModel
TEMPLATE = app

# The following define makes your compiler emit warnings if you use
# any feature of Qt which has been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0


SOURCES += \
        main.cpp \
        dialog.cpp

HEADERS += \
        dialog.h

FORMS += \
        dialog.ui

DISTFILES +=

RESOURCES += \
    resource.qrc

dialog.cpp

#include "dialog.h"
#include "ui_dialog.h"

#include <QComboBox>
#include <QSqlTableModel>
#include <QHeaderView>
#include <QTableView>
#include <QTimer>
#include <QLineEdit>
#include <QCompleter>
#include <QSqlQuery>
#include <QSqlError>
#include <QSqlResult>

#include <QDebug>

Dialog::Dialog(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::Dialog)
{
    ui->setupUi(this);

    model = new QSqlTableModel;

    completer.setModel(model);
    ui->lineEdit->setCompleter(&completer);
    completer.setCompletionColumn(2);
    model->setTable("TableTest");
    model->select();

    ui->tableView->setModel(model);
}

Dialog::~Dialog()
{
    delete ui;
}

dialog.h

#ifndef DIALOG_H
#define DIALOG_H

#include <QCompleter>
#include <QDialog>
#include <QSqlTableModel>

namespace Ui {
class Dialog;
}

class Dialog : public QDialog
{
    Q_OBJECT

public:
    explicit Dialog(QWidget *parent = 0);
    ~Dialog();

private:
    Ui::Dialog *ui;
    QSqlTableModel *model;
    QCompleter completer;

};

#endif // DIALOG_H

dialog.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>Dialog</class>
 <widget class="QDialog" name="Dialog">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>274</width>
    <height>243</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Dialog</string>
  </property>
  <layout class="QVBoxLayout" name="verticalLayout">
   <item>
    <layout class="QHBoxLayout" name="horizontalLayout">
     <item>
      <widget class="QLabel" name="label">
       <property name="text">
        <string>Select Country:</string>
       </property>
      </widget>
     </item>
     <item>
      <widget class="QLineEdit" name="lineEdit"/>
     </item>
    </layout>
   </item>
   <item>
    <widget class="QTableView" name="tableView"/>
   </item>
  </layout>
 </widget>
 <layoutdefault spacing="6" margin="11"/>
 <resources/>
 <connections/>
</ui>

main.cpp

#include "dialog.h"
#include <QApplication>
#include <QFile>
#include <QMessageBox>
#include <QSqlDatabase>
#include <QSqlQuery>
#include <QSqlError>

#include <QDebug>

static bool createConnection()
{
    QSqlDatabase db = QSqlDatabase::addDatabase("QSQLITE");
    db.setDatabaseName(":memory:");
    if (!db.open()) {
        QMessageBox::critical(0, qApp->tr("Cannot open database"),
                              qApp->tr("Unable to establish a database connection.\n"
                                       "This example needs SQLite support. Please read "
                                       "the Qt SQL driver documentation for information how "
                                       "to build it.\n\n"
                                       "Click Cancel to exit."), QMessageBox::Cancel);
        return false;
    }

    const QString tablename = "TableTest";

    //data of http://peric.github.io/GetCountries/
    QFile file(":/all.csv");
    if (!file.open(QIODevice::ReadOnly)) {
        qDebug() << file.errorString();
        return 1;
    }

    QStringList headers = QString(file.readLine()).trimmed()
            .replace('-', '_')
            .replace(QString("\""),QString("")).split(",");
    QSqlQuery query;
    QString str = QString("create table %1 (id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT").arg(tablename);
    for(QString header: headers){
        str += QString(",%1 VARCHAR(20)").arg(header);
    }
    str += ")";
    query.exec(str);

    QString insert = QString("insert into %1(").arg(tablename);
    for(const QString header: headers){
        insert += header+",";
    }
    insert.chop(1);
    insert += ") values (";
    for(int i=0; i < headers.count(); i++){
        insert += QString(" '%%1',").arg(i+1);
    }
    insert.chop(1);
    insert += ")";
    while (!file.atEnd()) {
        QString line = insert;
        for(QString col:  QString(file.readLine()).trimmed().split("\",")){
            line = line.arg(col.replace(QString("\""), QString("")));
        }
        query.exec(line);
    }
    return true;
}

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    if (!createConnection())
        return 1;
    Dialog w;
    w.show();
    return a.exec();
}

resource.qrc

<RCC>
    <qresource prefix="/">
        <file>all.csv</file>
    </qresource>
</RCC>