Prepared Statements in VB.NET

Question

I am new to prepared statements in vb.net and Microsoft SQL Server 2008. I can't really find any good sources for connecting to a database via connection string and executing prepared statements. Could someone show me an example or point me to a resource that might be useful?

Answer 1

Here's some quick example code:

Using cn  As New SqlConnection("your connection string here"), _
      cmd AS New SqlCommand("SELECT * FROM Table WHERE ID= @ID", cn)

    cmd.Parameters.Add("@ID", SqlDbType.Int).Value = 12345

    cn.Open()
    Using rdr As SqlDataREader = cmd.ExecuteReader()
        While rdr.Read()
            'Do something with the record
        End While
        rdr.Close()
    End Using
End Using

Of course you need to Import System.Data and System.Data.SqlClient.

Answer 2

Prepared statements are nothing but Parametrized SqlCommands enclosed in a Transaction.

For example, this is a Prepared Statement:

Using c As New SqlConnection(ConfigurationManager.ConnectionStrings("ConnectionString").ConnectionString)
   c.Open()
using mytransaction = c.BeginTransaction()

   Dim command = New SqlCommand("INSERT INTO yourtable(image) values (@image)", c)
   ''# this is specific to the FileUploadControl but the idea is to get the
   ''#image in a byte array; however you do it, it doesn't matter
    Dim buffer(FileUpload1.PostedFile.ContentLength) As Byte
    FileUpload1.PostedFile.InputStream.Read(buffer, 0, buffer.Length)
    command.Parameters.AddWithValue("@image", buffer)
    command.ExecuteNonQuery()    
 mytransaction .Commit()
End Using
End Using