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From: Josh Berkus <josh@agliodbs.com>
Reply-To: josh@agliodbs.com
Organization: Aglio Database Solutions
To: pgsql-sql@postgresql.org
Subject: Proposal for Clean-up of Conversion Functions
Date: Sun, 29 Sep 2002 13:38:14 -0700
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Postgres Folks,

As long as we're talking about the ToDo list, I'd like to make some simple=
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proposals regarding Postgres' conversion functions.

1) Addition of remaing to_char functions:  We should add to_char functions =
for=20
the following datatypes:
to_char(interval, 'format string') (I believe this is already in the todo)
to_char(inet, 'format string')

2) Addition of the following to-datatype conversion functions:
to_inet(text, optional 'format string')
to_interval(text, optional 'format string')
to_time(text, optional 'format string')
Without the "format string" these functions would operate like the current=
=20
"Interval" and "time" functions, but not require quoting the function name.

3) Addition of datatype testing functions.  All of these functions would te=
st=20
whether a text value is CASTable or transformable as the specific datatype=
=20
and return a boolean value *without* raising an exception.  The absence of=
=20
analogous functions is one of many issues holding back PL/pgSQL from PL/SQL=
=20
parity, as data type validation must take place outside functions.

is_timestamp(text, optional 'format string')
is_interval(text, optional 'format string')
is_time(text, optional 'format string')
is_date(text, optional 'format string')
is_inet(text, optional 'format string')
is_number(text, optional 'format string')


--=20
-Josh Berkus
 Aglio Database Solutions
 San Francisco