Maybe the best option is what Jack has already suggested, to have all in 1 DB in separate schemas (if tables are not already organised in separated schemas...)... But I am not sure I understand well problems:
1) Copy tables from Administrative to Application: this approach would work, but I have trouble with the foreign keys. I'll have to disable (or drop) them, then copy data, then activate (or recreate them again). Could lead to problems? 2) dblink: I can't use foreign key to foreign tables. Also, it is very hard to implement with JPA.
1) I guess data just need to be coppied in proper order... though, Postgres have deffered constraint feature, what means, FK will not break transaction until end (all trans commited) - untill all data copied...
2) I just wonder On what way it is possible in MS SQL Server or any other db engine? (to have FK to foreign table... )
