Updating Data ado.net tutorials

Tags: VB.NET, VB 2008, VB 2010, VB 2012, VB 2013

This lesson describes how to update data in a database

You frequently need to modify existing rows of data in a table using the UPDATE statement. When coding UPDATE statements, you must be careful to include a WHERE clause, because if you miss a WHERE clause, then you will change all the records of the table.

The Syntax of the Update Statement is as follows:

    UPDATE table-name SET column = expression [WHERE selection-criteria]
  

The following code shows you how to add a single row to a table:

    Dim ConnectionString As String = _
    "Data Source=SqlServerNameOrIP;Initial Catalog=DBName;Integrated Security=True"
    Dim connection As New SqlConnection(ConnectionString)
    Try
      connection.Open()

      ' declare and create a sql command object
      Dim command As SqlCommand = connection.CreateCommand

      ' set the sql statement to execute at the data source
      command.CommandText = _
      "UPDATE Users SET Password = @Password WHERE Username = @Username"

      ' add the parameters
      command.Parameters.AddWithValue("@Username", Username.Text)
      command.Parameters.AddWithValue("@Password", Password.Text)

      ' execute the sql statement against the connection
      command.ExecuteNonQuery()

      ' release the resources
      command.Dispose()
    Catch ex As Exception
      Console.Write(ex.Message)
    Finally
      ' close the connection
      connection.Close()
    End Try
  


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