[erlang-questions] How to control a table version in Mnesia?

[Dmitry Kolesnikov]

Hello,

Indeed auto-increments is use-full.

You can subscribe to schema table events: 
mnesia:subscribe({table, schema, detailed}). 

It gives you ability to trace changes and manipulate you custom version. 

Best Regards, 
Dmitry

On 14 Oct 2014, at 11:12, Shapovalov Taras <shapovalovts@REDACTED> wrote:

> Thank you, Dmitry,
> 
> The disadvantage of user_properties in my case is it is not auto-incremented by Mnesia upon table definition change (this feature would be useful for me). 
> 
> Best regards,
> 
> Taras
> 
> On Tue, Oct 14, 2014 at 11:10 AM, Dmitry Kolesnikov <dmkolesnikov@REDACTED> wrote:
> Hello,
> 
> You can use user_properties features of amnesia tables if you need some version for accounting.
> 
> mnesia:create_table(myt, [{user_properties, [{vsn, 1}]}]).
> amnesia:table_info(myt, user_properties).
> [{vsn,1}]
> 
> 
> - Dmitry
> 
> On 14 Oct 2014, at 09:33, Shapovalov Taras <shapovalovts@REDACTED> wrote:
> 
> > Hi guys,
> >
> > Do you know if there is a safe way to increment a table version (in Mnesia schema) with some value (>1) or just set its value into a particular version? In my case Mnesia runs only in a local mode (and will never be distributed) and as far as I understand the version is not really used in the local mode, so I would like to utilize it for my purposes.
> >
> > By some reason mnesia_lib:set() does not really work for me. In fact after I call that function and then request the table version, it seems it is changed, but ets:tab2list(schema) shows that it did not (and after I restart Mnesia, the requested version returns to the old value).
> >
> > Best regards,
> >
> > Taras
> > _______________________________________________
> > erlang-questions mailing list
> > erlang-questions@REDACTED
> > http://erlang.org/mailman/listinfo/erlang-questions
> 
> 
> 
> 
> -- 
> /T

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