This is not a Perl related question directly. But indirectly it might evolve into a very useful Perl module for users of DBI. Or maybe what I want exists already and have I just not been able to find it.

What I'm looking for is a Perl module that will take two SQL CREATE TABLE definitions (in the same dialect of SQL) and finds out whether they're different in functionality. If and only if they are different, then a method taking a database handle should make the necessary changes to the table in question in a transparent manner.

An example (in MySQL). Before:

CREATE TABLE foo (
  id int unsigned primary key,
  name varchar(255)
)
[download]

After:

CREATE TABLE foo (
  id int unsigned primary key,
  name varchar(255),
  status tinyint unsigned
)
[download]

Would execute:

ALTER TABLE foo ADD status tinyint unsigned
[download]

It seems that Alzabo is doing something like this under the covers. But I want to have this as a stand-alone module.

Class::AutoDB seems to offer some ideas in this direction as well, but claims the automatic update to be overkill for their application of the module.

Other modules that seem to go in this direction are DBIx-DBSchema, SQL::Schema and DB::Introspector. They all seem to be about abstracting table definitions, but not about updating actual table schema in the database itself.

Some of my questions:

• Am I re-inventing the wheel here?
• Have I missed other generally available modules that do something related to this?
• Should I just extract what I need from Alzabo?

Any feedback will be very much appreciated.

Liz