Unused index in mnesia table

Sean Hinde <>
Fri Nov 19 00:05:34 CET 2004


On 18 Nov 2004, at 12:26, Goran Bage wrote:

> Dan Gudmundsson wrote:
>> How unique was the index keys?
>
> They were all the same as you noticed, I was aware of the fact that 
> all were the same and undefined. But I did not know this was a problem 
> and maybe there are
> others that may get the same problem, or am I the only one that plan 
> ahead :-)

This one also caused me much confusion several years ago, and still 
trips up certain members of the team have here ;-)

I think it should really have a prominent warning in the documentation.

My normal solution in the case where many rows will have the same value 
of secondary key, but it is still needed for the few rows which are 
different is to store a suitably tagged copy of the primary key in the 
secondary index field instead of blanks.

Sean




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