Dagfinn Ilmari Mannsåker > DBIx-Class-Schema-Loader-0.04005 > DBIx::Class::Schema::Loader

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Module Version: 0.04005   Source   Latest Release: DBIx-Class-Schema-Loader-0.07040

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(
      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, DBD::SQLite, 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_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

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',
        { 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", { debug => 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',
        { debug => 1, dump_directory => './lib' },
        [ 'dbi:Pg:dbname="foo"','postgres' ],
    );

rescan

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.

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(
      debug         => 1,
  );
  __PACKAGE__->connection('dbi:SQLite:example.db');

  1;

and remove the Main directory tree (optional). Every thing else should work the same

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.

SEE ALSO ^

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

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