Question

Is it possible to create a view from tables from two different databases? Like:

creative view 'my_view' as
  select names as value
  from host_a.db_b.locations 
  union 
  select description as value 
  from host_b.db_b.items;

They currently are different database engines (MyISAM and InnoDB).

thx in advance

Answer 1

Yes, you need to access the remote table via the FEDERATED db engine, then create a view using your query.

However this is a rather messy way to solve the problem – particularly as (from your example query) your data is effectively sharded.

This structure won’t allow updates/inserts on the view. Even for an updatable/insertable view, my gut feeling is that you’ll run into problems if you try to anything other than auto-commit transactions, particularly as you’re mixing table types. I’d recommend looking at replication as a better way to solve the problem.