NAME
DBIx::Class::Schema::Loader - Dynamic definition of a DBIx::Class::Schema
SYNOPSIS
package My::Schema;
use base qw/DBIx::Class::Schema::Loader/;
__PACKAGE__->loader_options(
relationships => 1,
constraint => '^foo.*',
# debug => 1,
);
# in seperate application code ...
use My::Schema;
my $schema1 = My::Schema->connect( $dsn, $user, $password, $attrs);
# -or-
my $schema1 = "My::Schema"; $schema1->connection(as above);
=head1 DESCRIPTION
DBIx::Class::Schema::Loader automates the definition of a
L<DBIx::Class::Schema> by scanning database table definitions and
setting up the columns and primary keys.DBIx::Class::Schema::Loader currently supports DBI for MySQL, Postgres, SQLite and DB2.
See DBIx::Class::Schema::Loader::DBI::Writing for notes on writing your own vendor-specific subclass for an unsupported DBD driver.
This module requires DBIx::Class 0.06 or later, and obsoletes the older DBIx::Class::Loader.
This module is designed more to get you up and running quickly against an existing database, or to be effective for simple situations, rather than to be what you use in the long term for a complex database/project.
That being said, transitioning your code from a Schema generated by this module to one that doesn't use this module should be straightforward and painless (as long as you're not using any methods that are now deprecated in this document), so don't shy away from it just for fears of the transition down the road.
METHODS
loader_options
Example in Synopsis above demonstrates a few common arguments. For detailed information on all of the arguments, most of which are only useful in fairly complex scenarios, see the DBIx::Class::Schema::Loader::Base documentation.
This method is *required*, for backwards compatibility reasons. If you do not wish to change any options, just call it with an empty argument list during schema class initialization.
connection
See DBIx::Class::Schema. Our local override here is to hook in the main functionality of the loader, which occurs at the time the connection is specified for a given schema class/object.
clone
See DBIx::Class::Schema. Our local override here is to make sure cloned schemas can still be loaded at runtime by copying and altering a few things here.
dump_to_dir
Argument: directory name.
Calling this as a class method on either DBIx::Class::Schema::Loader or any derived schema class will cause all affected schemas to dump manual versions of themselves to the named directory when they are loaded. In order to be effective, this must be set before defining a connection on this schema class or any derived object (as the loading happens at connection time, and only once per class).
See "dump_directory" in DBIx::Class::Schema::Loader::Base for more details on the dumping mechanism.
This can also be set at module import time via the import option dump_to_dir:/foo/bar to DBIx::Class::Schema::Loader, where /foo/bar is the target directory.
Examples:
# My::Schema isa DBIx::Class::Schema::Loader, and has connection info
# hardcoded in the class itself:
perl -MDBIx::Class::Schema::Loader=dump_to_dir:/foo/bar -MMy::Schema -e1
# Same, but no hard-coded connection, so we must provide one:
perl -MDBIx::Class::Schema::Loader=dump_to_dir:/foo/bar -MMy::Schema -e 'My::Schema->connection("dbi:Pg:dbname=foo", ...)'
# Or as a class method, as long as you get it done *before* defining a
# connection on this schema class or any derived object:
use My::Schema;
My::Schema->dump_to_dir('/foo/bar');
My::Schema->connection(........);
# Or as a class method on the DBIx::Class::Schema::Loader itself, which affects all
# derived schemas
use My::Schema;
use My::OtherSchema;
DBIx::Class::Schema::Loader->dump_to_dir('/foo/bar');
My::Schema->connection(.......);
My::OtherSchema->connection(.......);
# Another alternative to the above:
use DBIx::Class::Schema::Loader qw| dump_to_dir:/foo/bar |;
use My::Schema;
use My::OtherSchema;
My::Schema->connection(.......);
My::OtherSchema->connection(.......);make_schema_at
This simple function allows one to create a Loader-based schema in-memory on the fly without any on-disk class files of any kind. When used with the dump_directory option, you can use this to generate a rought draft manual schema from a dsn without the intermediate step of creating a physical Loader-based schema class.
This function can be exported/imported by the normal means, as illustrated in these Examples:
# Simple example...
use DBIx::Class::Schema::Loader qw/ make_schema_at /;
make_schema_at(
'New::Schema::Name',
{ relationships => 1, debug => 1 },
[ 'dbi:Pg:dbname="foo"','postgres' ],
);
# Complex: dump loaded schema to disk, all from the commandline:
perl -MDBIx::Class::Schema::Loader=make_schema_at,dump_to_dir:./lib -e 'make_schema_at("New::Schema::Name", { relationships => 1 }, [ 'dbi:Pg:dbname="foo"','postgres' ])'
# Same, but inside a script, and using a different way to specify the
# dump directory:
use DBIx::Class::Schema::Loader qw/ make_schema_at /;
make_schema_at(
'New::Schema::Name',
{ relationships => 1, debug => 1, dump_directory => './lib' },
[ 'dbi:Pg:dbname="foo"','postgres' ],
);EXAMPLE
Using the example in DBIx::Class::Manual::ExampleSchema as a basis replace the DB::Main with the following code:
package DB::Main;
use base qw/DBIx::Class::Schema::Loader/;
__PACKAGE__->loader_options(
relationships => 1,
debug => 1,
);
__PACKAGE__->connection('dbi:SQLite:example.db');
1;and remove the Main directory tree (optional). Every thing else should work the same
DEPRECATED METHODS
You don't need to read anything in this section unless you're upgrading code that was written against pre-0.03 versions of this module. This version is intended to be backwards-compatible with pre-0.03 code, but will issue warnings about your usage of deprecated features/methods.
load_from_connection
This deprecated method is now roughly an alias for "loader_options".
In the past it was a common idiom to invoke this method after defining a connection on the schema class. That usage is now deprecated. The correct way to do things from now forward is to always do loader_options on the class before connect or connection is invoked on the class or any derived object.
This method *will* dissappear in a future version.
For now, using this method will invoke the legacy behavior for backwards compatibility, and merely emit a warning about upgrading your code.
It also reverts the default inflection scheme to use Lingua::EN::Inflect just like pre-0.03 versions of this module did.
You can force these legacy inflections with the option legacy_default_inflections, even after switch over to the preferred "loader_options" way of doing things.
See the source of this method for more details.
loader
This is an accessor in the generated Schema class for accessing the DBIx::Class::Schema::Loader::Base -based loader object that was used during construction. See the DBIx::Class::Schema::Loader::Base docs for more information on the available loader methods there.
This accessor is deprecated. Do not use it. Anything you can get from loader, you can get via the normal DBIx::Class::Schema methods, and your code will be more robust and forward-thinking for doing so.
If you're already using loader in your code, make an effort to get rid of it. If you think you've found a situation where it is neccesary, let me know and we'll see what we can do to remedy that situation.
In some future version, this accessor *will* disappear. It was apparently quite a design/API mistake to ever have exposed it to user-land in the first place, all things considered.
KNOWN ISSUES
Multiple Database Schemas
Currently the loader is limited to working within a single schema (using the database vendors' definition of "schema"). If you have a multi-schema database with inter-schema relationships (which is easy to do in Postgres or DB2 for instance), you only get to automatically load the tables of one schema, and any relationships to tables in other schemas will be silently ignored.
At some point in the future, an intelligent way around this might be devised, probably by allowing the db_schema option to be an arrayref of schemas to load, or perhaps even offering schema constraint/exclusion options just like the table ones.
In "normal" DBIx::Class::Schema usage, manually-defined source classes and relationships have no problems crossing vendor schemas.
AUTHOR
Brandon Black, blblack@gmail.com
Based on DBIx::Class::Loader by Sebastian Riedel
Based upon the work of IKEBE Tomohiro
THANK YOU
Adam Anderson, Andy Grundman, Autrijus Tang, Dan Kubb, David Naughton, Randal Schwartz, Simon Flack, Matt S Trout, everyone on #dbix-class, and all the others who've helped.
LICENSE
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.