Introducing ErlyDB: The Erlang Twist on Database Abstraction

Vlad Dumitrescu <>
Wed Aug 30 22:39:03 CEST 2006


On 8/30/06, Yariv Sadan <> wrote:
> Thanks for the thoughts. I think these are very valid points. It
> wouldn't be hard to hack Smerl into just spitting out the BEAM files
> to a directory. This way, all new app code can be deployed at once.

Or better, to call it at compile time. The simple way is to use Ulf
Wiger's contribution from trapexit "parse transform to evaluate code
at compile time" or something like that.

> However -- it should possible to use ErlyDB without taking the system
> offline if all schema changes are non-destructive. You would first
> update the schema, then call erlydb:code_gen, then load the new
> application modules. This way, everything should work. I haven't tried
> it, though :)

If you have a process using the old definitions that is running when
the schema is updated, it might crash. Hopefully it is only a
transient process.

OTOH, modifying the schema is difficult to do smoothly with any
system, so one isn't worse in this case :-)

regards,
Vlad



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