Re: BUG #4421: convert_to() should be immutable

Tom Lane schrieb:
> Andreas Peer <andipeer@gmx.net> writes:
>
>> Well, the use case is a strange one... I would like to use a varchar()
>> column for storing a variable-length vector of integers. The numbers are
>> represented by the codepoints. Therefore, I need to sort them as binary
>> data, not as characters. I would often need to get all the vectors that
>> lie in between to vectors, therefore I need the "binary" index.
>>
>
> Use bytea maybe?
>
>
Than I cannot access the single characters anymore (or I just use bytes,
but that limits a number to 256...)
>> And the code should be as database independent as possible, therefore I
>> cannot use an array or another data type that may not be supported by
>> other DBMS.
>>
>
> I can't imagine how you'd think that a functional index on convert_to()
> would be the most portable solution ...
>
nearly every DBMS has a function for converting character strings to
binary strings, I would just have to change the function
name/parameters, but the rest of the query could be the same
>             regards, tom lane
>
>
Regards,
Andreas Peer