how to search a date by using basic date picker for oracle ?

Private Function GetDate( ByVal bdp1 As date) As DataSet

        Dim connectionString As String = "Data Source = abc; User ID = ***; Password = ***;"
        Dim sqlConnection As OracleClient.OracleConnection = New OracleClient.OracleConnection(connectionString)


        Dim queryString As String = "select * from table_abc where (column_name<= to_date( 'user_input' ,'MM/DD/YYYY') and column_name > to_date( 'user_input' ,'MM/DD/YYYY')

        Dim sqlCommand As OracleClient.OracleCommand = New OracleClient.OracleCommand(queryString, sqlConnection)
        sqlCommand.CommandTimeout = 0

        sqlCommand.Parameters.Add(New OracleParameter(":bdp1", OracleType.DateTime)).Value = bdp1


        Dim dataAdapter As OracleClient.OracleDataAdapter = New OracleClient.OracleDataAdapter(sqlCommand)
        Dim dataSet As DataSet = New DataSet
        dataAdapter.Fill(dataSet)

        Return dataSet

    End Function