RES: [Bioperl-l] Mysql columns and Blast evalues

Stefan Kirov skirov at
Thu Mar 10 08:21:28 EST 2005

I think it should work OK. And I think the values you want to store are 
too small for float (53 is the smallest: you should use float(53,53), 
which defines both storage and display precision).
I am personally using Oracle so it is a differnt game. One thing you can 
do is store the exponent, even just as an integer:
my $exp=int(log($blast_eval));
my $exp=log($blast_eval);
and store it as float.
When you want to work with the number again:
my $blast_eval=1**$exp;

davila wrote:

>Hi Stefan,
>Thanks for the tips !
>I guess the problem of using VARCHAR could be the limitations to compare the real evalues, so if I want to do something or only show evalues greater or smaller than 1e-50 would it work ok ?
>I wonder to know what other (mysql) column types (any further details would be appreciated) colleagues are using to store their Blast evalues ?
>-----Mensagem original----- 
>De: Stefan Kirov [mailto:skirov at] 
>Enviada: qui 10/3/2005 00:25 
>Para: davila 
>Cc: bioperl-l at 
>Assunto: Re: [Bioperl-l] Mysql columns and Blast evalues

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