Book Image

Hands-On Mobile and Embedded Development with Qt 5

By : Lorn Potter
Book Image

Hands-On Mobile and Embedded Development with Qt 5

By: Lorn Potter

Overview of this book

Qt is a world-class framework, helping you to develop rich graphical user interfaces (GUIs) and multi-platform applications that run on all major desktop platforms and most mobile or embedded platforms. The framework helps you connect the dots across platforms and between online and physical experience. This book will help you leverage the fully-featured Qt framework and its modular cross-platform library classes and intuitive APIs to develop applications for mobile, IoT, and industrial embedded systems. Considerations such as screen size, device orientation changes, and small memory will be discussed. We will focus on various core aspects of embedded and mobile systems, such as connectivity, networking, and sensors; there is no IoT without sensors. You will learn how to quickly design a flexible, fast, and responsive UI that looks great. Going further, you will implement different elements in a matter of minutes and synchronize the UI elements with the 3D assets with high precision. You will learn how to create high-performance embedded systems with 3D/2D user interfaces, and deploy and test on your target hardware. The book will explore several new features, including Qt for WebAssembly. At the end of this book, you will learn about creating a full software stack for embedded Linux systems using Yocto and Boot to Qt for Device Creation.
Table of Contents (23 chapters)
Title Page
Dedication
About Packt
Foreword
Contributors
Preface
Index

Connecting to a local or remote database


Once we have the database configured and running, we can now connect to it using the same functions regardless of whether it is local or a remote database. Now, let's take a look at writing code to connect to a database, whether local or remote.

Databases are either locally available, which usually means on the same machine, or accessed remotely over a network. Connecting to these different databases using Qt is essentially the same. Not all databases support remote access. 

Let's begin by using a local database.

To use the sql module, we need to add sql to the profile:

QT += sql

To connect to a database in Qt, we need to use the QSqlDatabase class.

QSqlDatabase

Despite the name,QSqlDatabaserepresents a connection to a database, not the database itself.

To create a connection to a database, you first need to specify which database type you are using. It is referenced as a string representation of the supported database. Let's first choose the MySQL QMYSQL...