Skye Shaw wrote:
2011/2/9 Peter Rabbitson <[email protected]>:
Dagfinn Ilmari Mannsåker wrote:
Peter Rabbitson <[email protected]> writes:
Skye Shaw wrote:
Hello,
Is it possible to have DBIC populate a newly created instance with the
underlying table's defaults when a value isn't provided?
The reason is that having every insert be followed by a select is...
how shall I put it, insane?!
We already use INSERT ... RETURNING ... to get the ID if the DB supports
it, couldn't that be extended to get all the columns that weren't
specified in the ->new/->create call?
Right, and this will introduce an insane amount of broken code, since your
dev will work fine on a Pg version that supports IR, and will all of a
sudden stop working entirely in production on a different db or on an
older version of Pg, since now all the data you expected to be there is
suddenly UNDEF.
I do not know DBIx internals but, on the surface, DBI does provide the
column_info method. Sure underlying driver support for this method can
vary but are there really any DBs that DBIx currently supports that
don't provide a way to query table metadata?
Loading the metadata once, when the class is loaded, is all that's needed.
I am now confused - so you *do* want to get the default value automatically
from the db, but want to do it for simple values only? If so - then yes this
is somewhat doable, since the database introspection has gotten better (in
the sense that we now can deal with 50% of the corner cases compared to 5%
when default_value came to be). I can see the possibility of a DBIC extension
which:
* defines and maintains a new attribute for dbic-side defaults (which value
is taken at the same time when DBIx::Class::DynamicDefault would fire)
* if attribute value is not present, attempts to populate this attribute
automatically from the database, and sets it to undef if the retrieval
somehow failed (or if the default is non-trivial e.g. a function)
With that said - patches are certainly welcome, as long as we do not try to
give more meaning to the (badly named, but nevertheless) pre-existing
default_value
Cheers!
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