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);DESCRIPTION
DBIx::Class::Schema::Loader automates the definition of a DBIx::Class::Schema by scanning database table definitions and setting up the columns, primary keys, and relationships.
DBIx::Class::Schema::Loader currently supports only the DBI storage type. It has explicit support for DBD::Pg, DBD::mysql, DBD::DB2, and DBD::SQLite. Other DBI drivers may function to a greater or lesser degree with this loader, depending on how much of the DBI spec they implement, and how standard their implementation is. Patches to make other DBDs work correctly welcome.
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* at this time, 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.
Setting these options explicitly via this method after calling connection is deprecated and will stop working in version 0.04000. For now the code merely warns about this condition.
The preferred way of doing things is to either call loader_options before any connection is made, or embed the loader_options in the connection information itself as shown below.
connection
See DBIx::Class::Schema for basic usage.
If the final argument is a hashref, and it contains a key loader_options, that key will be deleted, and its value will be used for the loader options, just as if set via the "loader_options" method above.
The actual auto-loading operation (the heart of this module) will be invoked as soon as the connection information is defined.
clone
See DBIx::Class::Schema.
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 as soon as both a connection and loader_options are set, 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 rough draft manual schema from a dsn without the intermediate step of creating a physical Loader-based schema class.
The return value is the input class name.
This function can be exported/imported by the normal means, as illustrated in these Examples:
# Simple example, creates as a new class 'New::Schema::Name' in
# memory in the running perl interpreter.
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.
All of these deprecated methods will dissappear in version 0.04000, and converting code that uses these methods should be trivial.
load_from_connection
This deprecated method is now roughly an alias for "loader_options".
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" in DBIx::Class::Schema::Loader::Base, even after switch over to the preferred "loader_options" way of doing things. That option will not go away until at least 0.05.
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 necessary, 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 PostgreSQL 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.
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
Matt S Trout, all of the #dbix-class folks, and everyone who's ever sent in a bug report or suggestion.
LICENSE
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.