Re: Resolving polymorphic functions with related datatypes

2008/7/3 Simon Riggs <simon(at)2ndquadrant(dot)com>:
> I'm using the nvl() function from the orafce package. It is defined as a
> polymorphic function so its function signature is
> nvl(anyelement, anyelement)
>
> Now if I try to use the function in this very typical way
> nvl(numeric_col, 0)
>
> we get
>
> ERROR: function nvl(numeric, integer) does not exist
>
> The same error occurs if we have nvl(smallint, integer) etc
>
> This is a real shame 'cos polymorphic functions ought to be a great way
> of saving development time and catalog space, yet they seem to fall down
> a hole without implicit casting.
>
> What I'd like it to do is to recognise that the 0 should be cast
> implicitly to another datatype within the same family. I want and expect
> nvl(char_column, 0)
> to fail, but I expect the various numeric/integer types we have to play
> nicely together without tears.
>
> If we can do it for indexes, can we do it for polymorphic functions also
> when there is no matching function?
>

+1

there is similar problem with literal constant.

Pavel Stehule

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