DBIx::Class::Schema::Loader.3pm

Langue: en

Version: 2010-02-20 (fedora - 01/12/10)

Section: 3 (Bibliothèques de fonctions)

NAME

DBIx::Class::Schema::Loader - Dynamic definition of a DBIx::Class::Schema

SYNOPSIS

   ### use this module to generate a set of class files
 
   # in a script
   use DBIx::Class::Schema::Loader qw/ make_schema_at /;
   make_schema_at(
       'My::Schema',
       { debug => 1,
         dump_directory => './lib',
       },
       [ 'dbi:Pg:dbname="foo"', 'myuser', 'mypassword' ],
   );
 
   # from the command line or a shell script with dbicdump (distributed
   # with this module).  Do `perldoc dbicdump` for usage.
   dbicdump -o dump_directory=./lib \
            -o debug=1 \
            My::Schema \
            'dbi:Pg:dbname=foo' \
            myuser \
            mypassword
 
   ### or generate and load classes at runtime
   # note: this technique is not recommended
   # for use in production code
 
   package My::Schema;
   use base qw/DBIx::Class::Schema::Loader/;
 
   __PACKAGE__->loader_options(
       constraint              => '^foo.*',
       # debug                 => 1,
   );
 
   #### in application code elsewhere:
 
   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, DBD::SQLite, DBD::Sybase (for Sybase ASE and MSSSQL), DBD::ODBC (for MSSQL) and DBD::Oracle. 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 0.07006 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, so don't shy away from it just for fears of the transition down the road.

METHODS

loader_class

Argument: $loader_class

Set the loader class to be instantiated when ``connection'' is called. If the classname starts with ``::'', ``DBIx::Class::Schema::Loader'' is prepended. Defaults to ``storage_type'' in DBIx::Class::Schema (which must start with ``::'' when using DBIx::Class::Schema::Loader).

This is mostly useful for subclassing existing loaders or in conjunction with ``dump_to_dir''.

loader_options

Argument: \%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.

If you intend to use "loader_options", you must call "loader_options" before any connection is made, or embed the "loader_options" in the connection information itself as shown below. Setting "loader_options" after the connection has already been made is useless.

connection

Arguments: @args
Return Value: $new_schema

See ``connection'' in DBIx::Class::Schema for basic usage.

If the final argument is a hashref, and it contains the keys "loader_options" or "loader_class", those keys will be deleted, and their values value will be used for the loader options or class, respectively, just as if set via the ``loader_options'' or ``loader_class'' methods above.

The actual auto-loading operation (the heart of this module) will be invoked as soon as the connection information is defined.

clone

See ``clone'' in DBIx::Class::Schema.

dump_to_dir

Argument: $directory

Calling this as a class method on either DBIx::Class::Schema::Loader or any derived schema class will cause all 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

Arguments: $schema_class_name, \%loader_options, \@connect_info
Return Value: $schema_class_name

This function creates a DBIx::Class schema from an existing RDBMS schema. With the "dump_directory" option, generates a set of DBIx::Class classes from an existing database schema read from the given dsn. Without a "dump_directory", creates schema classes in memory at runtime without generating on-disk class files.

For a complete list of supported loader_options, see DBIx::Class::Schema::Loader::Base

This function can be imported in the usual way, 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',
         { debug => 1 },
         [ 'dbi:Pg:dbname="foo"','postgres' ],
     );
 
     # Inside a script, specifying a dump directory in which to write
     # class files
     use DBIx::Class::Schema::Loader qw/ make_schema_at /;
     make_schema_at(
         'New::Schema::Name',
         { debug => 1, dump_directory => './lib' },
         [ 'dbi:Pg:dbname="foo"','postgres' ],
     );
 
 

rescan

Return Value: @new_monikers

Re-scans the database for newly added tables since the initial load, and adds them to the schema at runtime, including relationships, etc. Does not process drops or changes.

Returns a list of the new monikers added.

naming

Arguments: \%opts | $ver

Controls the naming options for backward compatibility, see ``naming'' in DBIx::Class::Schema::Loader::Base for details.

To upgrade a dynamic schema, use:

     __PACKAGE__->naming('current');
 
 

Can be imported into your dump script and called as a function as well:

     naming('v4');
 
 

use_namespaces

Arguments: 1|0

Controls the use_namespaces options for backward compatibility, see ``use_namespaces'' in DBIx::Class::Schema::Loader::Base for details.

To upgrade a dynamic schema, use:

     __PACKAGE__->use_namespaces(1);
 
 

Can be imported into your dump script and called as a function as well:

     use_namespaces(1);
 
 

KNOWN ISSUES

Multiple Database Schemas

Currently the loader is limited to working within a single schema (using the underlying RDBMS's 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 currently can only automatically load the tables of one schema, and 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.

ACKNOWLEDGEMENTS

Matt S Trout, all of the #dbix-class folks, and everyone who's ever sent in a bug report or suggestion.

Based on DBIx::Class::Loader by Sebastian Riedel

Based upon the work of IKEBE Tomohiro

AUTHOR

blblack: Brandon Black <blblack@gmail.com>

CONTRIBUTORS

ilmari: Dagfinn Ilmari Mannsa°ker <ilmari@ilmari.org>

arcanez: Justin Hunter <justin.d.hunter@gmail.com>

ash: Ash Berlin <ash@cpan.org>

Caelum: Rafael Kitover <rkitover@cpan.org>

TSUNODA Kazuya <drk@drk7.jp>

rbo: Robert Bohne <rbo@cpan.org>

ribasushi: Peter Rabbitson <ribasushi@cpan.org>

gugu: Andrey Kostenko <a.kostenko@rambler-co.ru>

jhannah: Jay Hannah <jay@jays.net>

rbuels: Robert Buels <rmb32@cornell.edu>

timbunce: Tim Bunce <timb@cpan.org>

mst: Matt S. Trout <mst@shadowcatsystems.co.uk>

kane: Jos Boumans <kane@cpan.org>

waawaamilk: Nigel McNie <nigel@mcnie.name>

acmoore: Andrew Moore <amoore@cpan.org>

bphillips: Brian Phillips <bphillips@cpan.org>

schwern: Michael G. Schwern <mschwern@cpan.org>

hobbs: Andrew Rodland <arodland@cpan.org>

... and lots of other folks. If we forgot you, please write the current maintainer or RT.

Copyright (c) 2006 - 2009 by the aforementioned ``AUTHOR'' in DBIx::Class::Schema::Loader and ``CONTRIBUTORS'' in DBIx::Class::Schema::Loader.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

DBIx::Class, DBIx::Class::Manual::ExampleSchema