Mnesia -- multiple schemas?

Chris Pressey <>
Fri Feb 22 08:37:32 CET 2002


On Thu, 21 Feb 2002 17:46:38 -0800
Kurt Luoto <> wrote:

> When Mnesia is running in an Erlang node, is there only one "schema",
one
> database at any given time? Or can a Mnesia instance support multiple
> schemas at the same time?

In my experience, Mnesia only supports a single schema per node.

Maybe what would be useful for a sparse distribution topology would be
some sort of mostly-but-not-entirely transparent 'bridge' to connect two
different groups of nodes.  Not sure how that would work though.

What I would really like would be if Mnesia could add or remove nodes from
its schema after the schema has been created (perhaps I am living in a
fantasy world though.)  All nodes must be up and have mnesia stopped while
creating or destroying a schema (but they must have mnesia started when
creating tables.)  This is a bit tiresome to manually set up on a large
number of nodes, and pretty much rules out ad hoc deployment.  If anyone
knows a nifty trick to make this more painless, I'm all ears  :)

Chris



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