> I would like to be able to define the type of column
> A in table T to
> be the same as the type of column B in table U,
> *whatever this type
> may be*. In particular, if later I change the type
> of column U.B, I
> don't want to have to explicitly change the type of
> column T.A.
>
> I have asked many people about how to do this, and
> the consensus seems
> to be that it can't be done, at least in PostgreSQL.
>
> (PL/pgSQL has tablename.columnname%TYPE
> pseudo-types, but these are
> not available in PostgreSQL SQL.)
>
> I find the absence of this feature hard to
> understand.
>
> After all, in a RDBMS, references between tables
> (which require that
> the referring and referred-to columns have matching
> types) is not only
> extremely common but downright *essential* to the
> whole relational
> approach to organizing data.
>
> (Another potential solution would be to use CREATE
> TYPE to create a
> "composite type" having only one element. Then any
> changes could be
> localized to changing the definition of the new
> type. But using a
> composite type for what really should be a scalar
> type results in more
> inconveniences than the whole scheme purports to
> solve.)
>
> I'm sure I'm missing something huge, because this is
> just too perverse
> otherwise.
>
> What is it that I'm missing?
>
> Is there a best practice to handle this extremely
> common problem?
>
> Thanks!
>
> kj
can i ask a question? why are your column types
dynamic in nature?
my integers typcially stay as integers. my text
typically stays as text.
you can also put in a feature request so the
developers can review it.
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