Lesson 34: Database Introduction in VB2019

In this lesson, we transition from graphics and animation to database programming - a critical skill for building data-driven applications. Databases allow you to store, retrieve, and manipulate large amounts of information efficiently.

34.1 Introduction to Databases

In the past, people managed data manually using cards and folders. In today's digital age, computer-based database management systems handle data faster and more efficiently than manual methods. With network and Internet technologies, data can now be managed both locally and remotely.

Database management systems are essential for running:

• Payroll systems
• Inventory systems
• Accounting systems
• Payment systems
• Order handling systems
• Customer relationship management (CRM) systems

Popular commercial database management systems include:

34.2 Creating a Database Application

A database management system deals with storing, modifying, and extracting information from a database. While DBMS can be complex for non-technical users, we can create user-friendly database applications in VB2019 that handle these tasks with the DBMS running in the background.

Visual Basic 2019 uses ADO.NET to handle databases. ADO.NET works with advanced database management systems like Microsoft SQL Server.

Database Application Components

To build database applications in VB2019, we use several ADO.NET objects:

Object	Description	Namespace
SqlConnection	Connects to a data source in SQL Server	System.Data.SqlClient
DataTable	Stores data for navigation and manipulation	System.Data
DataAdapter	Populates a DataReader and updates data	System.Data.Common

These objects belong to the System.Data and System.Xml namespaces, so we need to reference them before we can use them.

Referencing ADO.NET Objects

1. Choose Project > Database Project Properties
2. Click the References tab
3. Under imported namespaces, ensure System.Data and System.Data.SqlClient are selected
4. Click Save All and return to the IDE

Figure 34.1: Adding required references

Form1.vb

' Import required namespaces
Imports System.Data
Imports System.Data.SqlClient

Public Class Form1
    Dim connectionString As String = "Server=myServerAddress;Database=myDataBase;User Id=myUsername;Password=myPassword;"
    Dim connection As New SqlConnection(connectionString)
    
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Try
            connection.Open()
            MessageBox.Show("Connection successful!")
        Catch ex As Exception
            MessageBox.Show("Connection failed: " & ex.Message)
        Finally
            If connection.State = ConnectionState.Open Then
                connection.Close()
            End If
        End Try
    End Sub
End Class

Sample Contacts Table

ID	Name	Email	Phone
1	John Smith	[email protected]	(555) 123-4567
2	Sarah Johnson	[email protected]	(555) 987-6543
3	Michael Brown	[email protected]	(555) 456-7890
4	Emily Davis	[email protected]	(555) 234-5678

Figure 34.2: Sample database table structure

Setting Up SQL Server

To follow along with this lesson, you'll need Microsoft SQL Server installed. You can download the free Express edition:

Next Lesson

Learn to connect to databases in Lesson 35: Connecting to Databases.

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