What do I do if I have complex table names not suitable for users?
The best way to present your users with a friendly and descriptive representation of your database is to create VIEWs. Reports can be configured to only look at your views with the ViewsOnly or VisibleDataSources setting.
See the security guide for more details on how to hide data sources.
Example SQL
CREATE VIEW Countries AS SELECT
[System_Internal_Country_Name] AS [CountryName]
FROM [Country]