Jim Starkey wrote:

>Thomas Steinmaurer wrote:
>
>
>
>>Hello,
>>
>>is there anything on the plan/roadmap for an extended usage of the
>>field/domain DEFAULT usage?
>>
>>It would be pretty neat being able to have something like that:
>>
>>CREATE DOMAIN D_ACTYEAR AS
>> INTEGER
>> DEFAULT (EXTRACT(YEAR FROM CURRENT_DATE))
>>;
>>
>>Basically, I'm asking for support of built-in functions and UDFs in the
>>DEFAULT clause.
>>
>>Would this be possible or is that already planned?
>>
>>

AFAIK, the main problem is in GBAK that will need to manage more
dependencies.

>Interesting question. The engine is designed to support this, and the
>original GDML did. The initial value is stored in the field
>RDB$DEFAULT_VALUE in RDB$FIELDS, which is defined as a BLR field. The
>problem is in the SQL DDL.
>
>I have no doubt that the SQL theorists will object, but in fact it takes
>exactly two lines in parse.y to implement what you ask:
>
>default_value : constant
> | current_user
> | current_role
> | internal_info
> | null_value
> | datetime_value_expression
>/* | '(' begin_trigger value end_trigger ')'
> { $$ = $3; }
>*/ ;
>
>(In fact, the constant, null value, and datetime_value_expression could
>be dropped for a net line loss of one).
>
>

Well, I already changed this in the past.
It works for basic expressions, but didn't work with expressions that
have SELECT, for example. Some problem with contexts, IIRC.
Some other thing need to be changed. :-)


Adriano