Public Class ClassDatabase
    Private Shared connectionString As String

    Public Shared Function Init()
        Try
            connectionString = MyConnectionString
            Dim SQLconnect As New SqlClient.SqlConnection
            SQLconnect.ConnectionString = connectionString
            SQLconnect.Open()
            SQLconnect.Close()
            If LogErrorsOnly = False Then ClassLogger.Add(" >> Database initiiert.")
            Return True
        Catch ex As Exception
            ClassLogger.Add("Fehler bei DatabaseInit: " & ex.Message, True)
            Return False
        End Try
    End Function

    Public Shared Function Return_Datatable(Select_anweisung As String, Optional CallMethod As String = "")
        Try
            Dim SQLconnect As New SqlClient.SqlConnection
            Dim SQLcommand As SqlClient.SqlCommand
            SQLconnect.ConnectionString = connectionString
            SQLconnect.Open()
            SQLcommand = SQLconnect.CreateCommand
            SQLcommand.CommandText = Select_anweisung

            Dim adapter1 As SqlClient.SqlDataAdapter = New SqlClient.SqlDataAdapter(SQLcommand)
            Dim dt As DataTable = New DataTable()
            adapter1.Fill(dt)
            SQLconnect.Close()
            Return dt
        Catch ex As Exception
            MsgBox("Fehler bei Return_Datatable: " & ex.Message & vbNewLine & vbNewLine & Select_anweisung & vbNewLine & vbNewLine & "Call-Method: " & CallMethod, MsgBoxStyle.Critical)
            ClassLogger.Add("Fehler bei Return_Datatable: " & ex.Message & "Call-Method: " & CallMethod, True)
            If CallMethod <> "" Then ClassLogger.Add(">> Call-Method: " & CallMethod, False)
            ClassLogger.Add(">> SQL: " & Select_anweisung, False)
            Return Nothing
        End Try
    End Function
    Public Shared Function Execute_non_Query(ExecuteCMD As String, Optional Userinput As Boolean = False)
        Try
            Dim SQLconnect As New SqlClient.SqlConnection
            Dim SQLcommand As SqlClient.SqlCommand
            SQLconnect.ConnectionString = connectionString
            SQLconnect.Open()
            SQLcommand = SQLconnect.CreateCommand
            'Update Last Created Record in Foo
            SQLcommand.CommandText = ExecuteCMD
            SQLcommand.ExecuteNonQuery()
            SQLcommand.Dispose()
            SQLconnect.Close()
            Return True
        Catch ex As Exception
            If Userinput = True Then
                MsgBox("Fehler bei Execute_non_Query: " & ex.Message & vbNewLine & vbNewLine & ExecuteCMD, MsgBoxStyle.Critical)

            End If
            ClassLogger.Add("Fehler bei Execute_non_Query: " & ex.Message, True)
            ClassLogger.Add("SQL: " & ExecuteCMD, False)
            Return False
        End Try
    End Function
    Public Shared Function Execute_Scalar(cmdscalar As String, Optional Userinput As Boolean = False)
        Dim result
        Try
            Dim SQLconnect As New SqlClient.SqlConnection
            Dim SQLcommand As SqlClient.SqlCommand
            SQLconnect.ConnectionString = connectionString
            SQLconnect.Open()
            SQLcommand = SQLconnect.CreateCommand
            'Update Last Created Record in Foo
            SQLcommand.CommandText = cmdscalar
            result = SQLcommand.ExecuteScalar()
            SQLcommand.Dispose()
            SQLconnect.Close()
            Return result
        Catch ex As Exception
            If Userinput = True Then
                MsgBox("Fehler bei Execute_Scalar: " & ex.Message & vbNewLine & vbNewLine & cmdscalar, MsgBoxStyle.Critical)
            End If
            ClassLogger.Add("Fehler bei Execute_Scalar: " & ex.Message, True)
            ClassLogger.Add("SQL: " & cmdscalar, False)
            Return Nothing
        End Try
    End Function
End Class