Imports System.Data.SqlClient
Imports System.Data
 
Public Class mssql_db
    Protected _isconnected As Boolean = False
    Protected connection As SqlConnection
 
    Public Function connect(ByVal server As String) As Boolean
        Dim connstring As String = "Data Source=" & server & ";Initial" & _
          "Catalog=" & "master" & ";Integrated Security=SSPI;"
        connection = New SqlConnection(connstring)
        Try
            connection.Open()
            _isconnected = True
        Catch ex As Exception
            MessageBox.Show(ex.Message + vbCrLf + ex.StackTrace, "Verbindung" & _
              "nicht möglich", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Function
 
    Public Function disconnect() As Boolean
        Try
            connection.Close()
            _isconnected = False
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Trennen nicht möglich", _
              MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
    End Function
 
    Public ReadOnly Property isconnected() As Boolean
        Get
            Return _isconnected
        End Get
    End Property
 
 
    Public Function query_db(ByVal query As String) As DataTable
 
        Dim adap As New SqlClient.SqlDataAdapter(query, connection)
        Dim t As New DataTable
        Try
            adap.Fill(t)
        Catch ex As Exception
            t.Columns.Add(New DataColumn("Exception"))
            t.Columns.Add(New DataColumn("Stacktrace"))
            Dim s() As String = {ex.Message, ex.StackTrace}
            t.Rows.Add(s)
        End Try
        Return t
    End Function
 
    Public Function create_client(ByVal hostname As String) As Boolean
        Dim query As String = "INSERT INTO testdatabase.dbo.clients " & _
        "(clientname) VALUES ('" & hostname & "')"
        Dim result As DataTable = query_db(query)
    End Function
 
 
End Class