VB.NET Sql Command Delete Statement Source Code Example
VB.NET Sql Command Delete Statement Source Code
Purpose: – Illustrates using Sql Command Delete statement and checking the result.
Prerequistes:
- Install Visual Basic (Express or Standard Edition)
- Install SQL Server Express
- Download Northwind Database
- Attach Northwind Database to Databases in Sql Express
Notes:
- Console Application is used to simplify things, but Windows Forms or Web Forms could also be used
- You can build a library of syntax examples by using same project over and over and just commenting out what you do not want to execute in Module1.vb
Instructions:
- Use VB 2008 (Express or Standard) Edition
- Create new project; select Console Application; name of Project could be VBNET_Syntax.
- Right-click project name in solution explorer; add new folder; name of folder could be DatabaseADONET
- Right-click folder; add class; class name could be clsSqlCommandDelete.vb
- Copy code into clsSqlCommandDelete.vb
- Copy code into Module1.vb
- Click green arrow to start with debugging
Step 1: Use View Plain to Cut-n-paste code into clsSqlCommandDelete.vb
Imports System Imports System.Data Imports System.Data.SqlClient Public Class clsSqlCommandDelete Sub Main() Dim thisConnection As New SqlConnection("server=(local)\SQLEXPRESS;" & _ "integrated security=sspi;database=Northwind") 'First insert some records 'Create Command object Dim nonqueryCommand As SqlCommand = thisConnection.CreateCommand() Try ' Open Connection thisConnection.Open() Console.WriteLine("Connection Opened") ' Create INSERT statement with named parameters nonqueryCommand.CommandText = _ "INSERT INTO Employees (FirstName, LastName) VALUES (@FirstName, @LastName)" ' Add Parameters to Command Parameters collection nonqueryCommand.Parameters.Add("@FirstName", SqlDbType.VarChar, 10) nonqueryCommand.Parameters.Add("@LastName", SqlDbType.VarChar, 20) ' Prepare command for repeated execution nonqueryCommand.Prepare() ' Data to be inserted Dim names() As String = {"Wade", "David", "Charlie"} For i As Integer = 0 To 2 nonqueryCommand.Parameters("@FirstName").Value = names(i) nonqueryCommand.Parameters("@LastName").Value = names(i) Console.WriteLine("Executing {0}", _ nonqueryCommand.CommandText) Console.WriteLine("Number of rows affected : {0}", _ nonqueryCommand.ExecuteNonQuery()) Next i Catch ex As SqlException ' Display error Console.WriteLine("Error: " & ex.ToString()) Finally ' Close Connection thisConnection.Close() Console.WriteLine("Connection Closed") End Try Try ' Open Connection thisConnection.Open() Console.WriteLine("Connection Opened") 'Create Command objects Dim scalarCommand As New SqlCommand("SELECT COUNT(*) FROM Employees", thisConnection) ' Execute Scalar Query Console.WriteLine("Before Delete, Number of Employees = {0}", _ scalarCommand.ExecuteScalar()) ' Set up and execute DELETE Command nonqueryCommand.CommandText = _ "DELETE FROM Employees WHERE " & _ "Firstname='Wade' AND Lastname='Wade' or " & _ "Firstname='Charlie' AND Lastname='Charlie' or " & _ "Firstname='David' AND Lastname='David' " Console.WriteLine("Executing {0}", nonqueryCommand.CommandText) Console.WriteLine("Number of rows affected : {0}", _ nonqueryCommand.ExecuteNonQuery()) ' Execute Scalar Query Console.WriteLine("After Delete, Number of Employee = {0}", _ scalarCommand.ExecuteScalar()) Catch ex As SqlException ' Display error Console.WriteLine("Error: " & ex.ToString()) Finally ' Close Connection thisConnection.Close() Console.WriteLine("Connection Closed") End Try Console.ReadLine() End Sub End Class |
Step 2: Use View Plain to Cut-n-paste code into Module1.vb
Module Module1 Sub Main() '***** DataBaseADONET ************* 'Dim mySQLConnectionConnectionString As New clsSQLConnectionConnectionString 'mySQLConnectionConnectionString.Main() 'Dim mySQLInsert As New clsSQLInsert 'mySQLInsert.Main() 'Dim mySQLParameters As New clsSQLParameters 'mySQLParameters.Main() 'Dim mySQLCallStoredProcedure As New clsSQLCallStoredProcedure 'mySQLCallStoredProcedure.Main() 'Dim mySQLSelect As New clsSQLSelect 'mySQLSelect.Main() Dim mySqlCommandDelete As New clsSqlCommandDelete mySqlCommandDelete.Main() End Sub End Module |