[erlang-questions] How do you transform a record properly?

Rob Charlton <>
Wed Mar 25 15:26:40 CET 2009


Hi,

I don't think mnesia minds, because it treats the table name differently 
from the record name used to access it. I just added a new field using 
the example from  here:
http://erlang.org/doc/apps/mnesia/Mnesia_chap3.html#3.1.1

In my own example, the table name and original record name was 
"rate_dest". The new record name was "rate_dest_new" which was identical 
apart from one extra field. After running the transform, I just added 
the new field to record rate_dest and deleted the definition of 
rate_dest_new.

Cheers

Rob

Bengt Kleberg wrote:
> Greetings,
>
> You are doing it the right way.
>
> Unless you change the name of the tuple when you change the contents.
> But that would perhaps be a problem for mnesia.
>
>
> bengt
>
> On Mon, 2009-03-23 at 20:18 -0700, ryeguy wrote:
>   
>> How would you add a field to a table using mnesia:table_transform? I
>> got it to work by just using a raw tuple in the function header, but
>> how do you match the old record, then output the new record with just
>> the new field added/changed?
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>
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-- 
Rob Charlton
Savage Minds Ltd
+44 20 79210521

skype: chocolatetpot
www.savageminds.com




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