This is what I ended up with. We're using FB 1.5 until 2.1.2 is
released. It will be nice when domains can be used in a CAST.
If I can reproduce it after migrating to 2.1 I'll post a bug. Otherwise
I won't, as minor bug support in 1.5 isn't a priority anymore.

ALTER TABLE MDDB_DRUG
ADD IS_BRAND CHAR(1) /*D_BOOLEAN*/ COMPUTED BY (CAST((CASE WHEN
MULTISRC='Y' THEN 'N' ELSE 'Y' END) AS CHAR(1))),
ADD ATOM_PKG_SZ DECIMAL(8,3) COMPUTED BY (CAST((CASE WHEN ATOM='Y'
THEN PKG_SZ ELSE NULL END) AS DECIMAL(8,3))),
ADD BRAND_NDC9 NUMERIC(9,0) /*D_NDC9*/ COMPUTED BY (CAST((CASE WHEN
MULTISRC<>'Y' THEN PID_CORE9 ELSE NULL END) AS NUMERIC(9,0)))
;

________________________________

From: firebird-support@yahoogroups.com
[mailto:firebird-support@yahoogroups.com] On Behalf Of Helen Borrie
Sent: Wednesday, March 04, 2009 5:31 PM
To: firebird-support@yahoogroups.com
Subject: Re: [firebird-support] Domains in computed columns



At 08:42 AM 5/03/2009, you wrote:

>If I define a computed column with an explicit data type, it works:
>
>FIELD_NAME DECIMAL(5,2) COMPUTED BY (...some formula...)
>
>If I use a domain name, I get an error message:
>
>ISC ERROR CODE:335544569
>ISC ERROR MESSAGE:
>Dynamic SQL Error
>SQL error code = -104
>Token unknown - line 21, char 24
>COMPUTED
>
>FIELD_NAME DOMAIN_NAME COMPUTED BY (...some formula...)
>
>
>Is this the expected behavior?

Well, it's surprising that you didn't get an exception in the first
case, since you can't specify the output data type of a computed column.


The second case is entirely as expected. The engine creates its own
domain for the computed column (as it does for real columns in the
absence of a domain specifier) but for obvious reasons it can't be
overridden. As Alexandre pointed out, if you need to force the data type
of the output, you can use a CAST in the expression.

The first case seems to be at least a quirk in the DDL parsing. If it
exists, it might be a carry-over that's been left intentionally so as
not to break legacy DDL in user apps. Other no-ops in the SQL language
have been progressively deprecated and eventually made exceptions. You
might like to post a description and a reproducible example in the
Tracker. If you do, make sure you say which version your observation
applies to.

./heLen

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