Database Developer

We have an electronic list of customer contact details and we need to create a database that can store this information so that it can be easily exported into a (preferably Excel) spreadsheet format to produce lists to use for promoting our other products and services.

We need to be able to regularly import information from spreadsheets relating to new and existing customer activity and also update/overwrite the previous transactions of existing customers so that when we come to extract the information the data relates either to their past history and their most recent activity.