Generated Primary and Foreign Keys for Distributed Databases

Any solution to extend or replace sequences as generated keys must meet the following requirements:

  1. They must guarantee uniqueness across multiple systems and databases.
  1. They must not impair the efficiency of clustered indexes as commonly implemented by RDBMSs.
  1. They must allow for the effective migration of pre-existing sequence-based databases.
  1. They must be reliable and maintainable.

.. A refinement of solution 3 is to create a single key column that encapsulates both the database identifier and a serial integer.