Re: inet value validation

["pgsql-general(at)list(dot)coretech(dot)ro" <pgsql-general(at)list(dot)coretech(dot)ro>]

yes, this is a good example, but I do not want to use an exception block 
because of the warning present on documentation regarding exception blocks
"*Tip: * A block containing an EXCEPTION clause is significantly more 
expensive to enter and exit than a block without one. Therefore, don't 
use EXCEPTION without need."

I intend to use this function heavily.


Razvan Radu

Andreas Kretschmer wrote:
> pgsql-general(at)list(dot)coretech(dot)ro <pgsql-general(at)list(dot)coretech(dot)ro> schrieb:
>
>   
> > hello,
> >
> > I want to write a function to validate an inet data type, but I figure that 
> > postgres should already have such a function to use before inserting values 
> > in inet type columns.
> > is it possible to access postgres's validation function for inet types ? I 
> > have snooped through the catalogs but I can not find such a function.
> >     
>
> You can try to cast a string into inet like this:
>
> test=# select '127.0.0.255'::inet;
>     inet
> -------------
>  127.0.0.255
> (1 row)
>
> test=# select '127.0.0.256'::inet;
> ERROR:  invalid input syntax for type inet: "127.0.0.256"
>
>
> Now you can write a little function to do this:
>
> ,----[  a little function  ]
> | create or replace function check_ip(varchar) returns bool as $$
> | declare
> |         i inet;
> | begin
> |         i := $1::inet;
> |         return 't'::bool;
> |         EXCEPTION WHEN invalid_text_representation then
> |                 return 'f'::bool;
> | end;
> | $$ language plpgsql immutable strict;
> `----
>
> You can use this function now inside a transaction.
>
>
>
> HTH, Andreas
>