[CDBI] State of the DBIx::Class Class::DBI compatibility layer

Michael G Schwern schwern at pobox.com
Thu Feb 14 00:31:09 GMT 2008


DBIx::Class::CDBICompat is in fantastic shape for anyone curious about 
transitioning from Class::DBI to DBIx::Class.  It's down to really niggling, 
undocumented details, like the exact particulars of when lazy loading happens.

The improved DBIx::Class::CDBICompat is not available on CPAN but only from 
its own branch.  It keeps up to date with trunk changes.  Eventually it will 
merge into trunk once I get the attention of a DBIC person for a couple hours.
http://dev.catalyst.perl.org/repos/bast/DBIx-Class/0.08/branches/cdbicompat_integration


The critical thing to realize is that this is *not* a subclass or wrapper 
around DBIx::Class but a series of plugins.  When you use CDBICompat you get 
DBIx::Class objects and all of DBIx::Class' features are available.  This 
allows one to ease into the new features offered by DBIx::Class without having 
to rewrite your whole code base.  One of the first things you'll want to look 
at is DBIx::Class::ResultSet for all it's advanced search() features.

The CDBICompat documentation has been improved a bit to make it clearer how to 
use it and what the limitations are.  You should be able to just change

	use base qw(Class::DBI);

with

	use base qw(DBIx::Class::CDBICompat);

with the important caveat that relationships (has_a, has_many...) have to be 
declared *after* all classes have been declared.


Bonus features:

$obj->{column} now works.  I didn't want to emulate that hack, but the folks 
who are paying me to do this needed it.  Ironically, because it goes through a 
tied scalar, it will be slower than $obj->column().

nocache() of Class::DBI::Plugin::NoCache is emulated so you can turn the 
object cache off.

search_where() of Class::DBI::AbstractSearch is emulated, though there's not 
much point because DBIC's search is almost exactly the same and better.


-- 
Life is like a sewer - what you get out of it depends on what you put into it.
     - Tom Lehrer




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