No VPD means (to me, at least), in order to support multiple customers, either implement data level security in the application or use multiple schemas (one per customer). Implementing data security in the application is a pain for so many reasons. Multiple schemas is equally painful.Oh well....
I don't disagree, if you want to support multiple customers on a single service - which is multi-tenancy in that service. It would probably be less of a pain to give each customer their own service and handle any required interactions with web service calls. Without being intimately familiar with your app and architecture, I couldn't say which would be less painful, but you do have options.
Hope this helps.
- Rick Greenwald