# Load plugins
use Catalyst qw/-Debug
- ConfigLoader
- Static::Simple
+ ConfigLoader
+ Static::Simple
- StackTrace
- /;
+ StackTrace
+ /;
B<Note:> Recent versions of C<Catalyst::Devel> have used a variety of
techniques to load these plugins/flags. For example, you might see
browser, not in the console window from which you're running your
application, which is where logging output usually goes.
+Make sure that when adding new plugins that you include them as a new
+dependancies within the Makefile.PL file. For example, after adding
+the StackTrace plugin the Makefile.PL should include the following
+line:
+
+ requires 'Catalyst::Plugin::StackTrace';
+
+
B<Notes:>
=over 4
# Retrieve all of the book records as book model objects and store in the
# stash where they can be accessed by the TT template
- # $c->stash->{books} = [$c->model('DB::Books')->all];
+ # $c->stash->{books} = [$c->model('DB::Book')->all];
# But, for now, use this code until we create the model later
$c->stash->{books} = '';
C<lib/MyApp/Controller/Books.pm> would match on the URL
C<http://localhost:3000/books/list> but "C<:Path('/list')>" would match
on C<http://localhost:3000/list>. You can use C<:Args()> to specify
-how many arguments an action should except. See
+how many arguments an action should accept. See
L<Catalyst::Manual::Intro/Action_types> for more information and a few
examples.
<tr>
<td>[% book.title %]</td>
<td>[% book.rating %]</td>
+ <td></td>
</tr>
[% END -%]
</table>
--
-- Create a very simple database to hold book and author information
--
- CREATE TABLE books (
+ CREATE TABLE book (
id INTEGER PRIMARY KEY,
title TEXT ,
rating INTEGER
);
- -- 'book_authors' is a many-to-many join table between books & authors
- CREATE TABLE book_authors (
+ -- 'book_author' is a many-to-many join table between books & authors
+ CREATE TABLE book_author (
book_id INTEGER,
author_id INTEGER,
PRIMARY KEY (book_id, author_id)
);
- CREATE TABLE authors (
+ CREATE TABLE author (
id INTEGER PRIMARY KEY,
first_name TEXT,
last_name TEXT
---
--- Load some sample data
---
- INSERT INTO books VALUES (1, 'CCSP SNRS Exam Certification Guide', 5);
- INSERT INTO books VALUES (2, 'TCP/IP Illustrated, Volume 1', 5);
- INSERT INTO books VALUES (3, 'Internetworking with TCP/IP Vol.1', 4);
- INSERT INTO books VALUES (4, 'Perl Cookbook', 5);
- INSERT INTO books VALUES (5, 'Designing with Web Standards', 5);
- INSERT INTO authors VALUES (1, 'Greg', 'Bastien');
- INSERT INTO authors VALUES (2, 'Sara', 'Nasseh');
- INSERT INTO authors VALUES (3, 'Christian', 'Degu');
- INSERT INTO authors VALUES (4, 'Richard', 'Stevens');
- INSERT INTO authors VALUES (5, 'Douglas', 'Comer');
- INSERT INTO authors VALUES (6, 'Tom', 'Christiansen');
- INSERT INTO authors VALUES (7, 'Nathan', 'Torkington');
- INSERT INTO authors VALUES (8, 'Jeffrey', 'Zeldman');
- INSERT INTO book_authors VALUES (1, 1);
- INSERT INTO book_authors VALUES (1, 2);
- INSERT INTO book_authors VALUES (1, 3);
- INSERT INTO book_authors VALUES (2, 4);
- INSERT INTO book_authors VALUES (3, 5);
- INSERT INTO book_authors VALUES (4, 6);
- INSERT INTO book_authors VALUES (4, 7);
- INSERT INTO book_authors VALUES (5, 8);
+ INSERT INTO book VALUES (1, 'CCSP SNRS Exam Certification Guide', 5);
+ INSERT INTO book VALUES (2, 'TCP/IP Illustrated, Volume 1', 5);
+ INSERT INTO book VALUES (3, 'Internetworking with TCP/IP Vol.1', 4);
+ INSERT INTO book VALUES (4, 'Perl Cookbook', 5);
+ INSERT INTO book VALUES (5, 'Designing with Web Standards', 5);
+ INSERT INTO author VALUES (1, 'Greg', 'Bastien');
+ INSERT INTO author VALUES (2, 'Sara', 'Nasseh');
+ INSERT INTO author VALUES (3, 'Christian', 'Degu');
+ INSERT INTO author VALUES (4, 'Richard', 'Stevens');
+ INSERT INTO author VALUES (5, 'Douglas', 'Comer');
+ INSERT INTO author VALUES (6, 'Tom', 'Christiansen');
+ INSERT INTO author VALUES (7, 'Nathan', 'Torkington');
+ INSERT INTO author VALUES (8, 'Jeffrey', 'Zeldman');
+ INSERT INTO book_author VALUES (1, 1);
+ INSERT INTO book_author VALUES (1, 2);
+ INSERT INTO book_author VALUES (1, 3);
+ INSERT INTO book_author VALUES (2, 4);
+ INSERT INTO book_author VALUES (3, 5);
+ INSERT INTO book_author VALUES (4, 6);
+ INSERT INTO book_author VALUES (4, 7);
+ INSERT INTO book_author VALUES (5, 8);
Then use the following command to build a C<myapp.db> SQLite database:
$ sqlite3 myapp.db
SQLite version 3.5.9
Enter ".help" for instructions
- sqlite> select * from books;
+ sqlite> select * from book;
1|CCSP SNRS Exam Certification Guide|5
2|TCP/IP Illustrated, Volume 1|5
3|Internetworking with TCP/IP Vol.1|4
Or:
- $ sqlite3 myapp.db "select * from books"
+ $ sqlite3 myapp.db "select * from book"
1|CCSP SNRS Exam Certification Guide|5
2|TCP/IP Illustrated, Volume 1|5
3|Internetworking with TCP/IP Vol.1|4
".q" to exit from SQLite from the SQLite interactive mode and return to
your OS command prompt.
+Please note that here we have chosen to use 'singular' table names. This
+is because the default inflection code for L<DBIx::Class:Schema::Loader>
+does NOT handle plurals. There has been much philosophical discussion
+on whether table names should be plural or singular. There is no one
+correct answer, as long as one makes a choice and remains consistent
+with it. If you prefer plural table names (e.g. they are easier and
+more natural to read) then you will need to pass it an inflect_map
+option. See L<DBIx::Class:Schema::Loader> for more information.
+
For using other databases, such as PostgreSQL or MySQL, see
L<Appendix 2|Catalyst::Manual::Tutorial::Appendices>.
=head1 DATABASE ACCESS WITH DBIx::Class
-Catalyst can be used with virtually any form of datastore available via
-Perl. For example, L<Catalyst::Model::DBI|Catalyst::Model::DBI> can be
-used to access databases through the traditional Perl C<DBI>
-interface. However, most Catalyst applications use some form of
-object-relational mapping (ORM) technology to create objects associated
-with tables in a relational database. Although L<Class::DBI|Class::DBI>
-has been a popular choice in the past, Matt Trout's
-L<DBIx::Class|DBIx::Class> (abbreviated as "DBIC") has rapidly emerged
-as the Perl-based ORM technology of choice. Most new Catalyst
-applications rely on DBIC, as will this tutorial.
+Catalyst can be used with virtually any form of datastore available
+via Perl. For example, L<Catalyst::Model::DBI|Catalyst::Model::DBI>
+can be used to access databases through the traditional Perl C<DBI>
+interface or you can use a model to access files of any type on the
+filesystem. However, most Catalyst applications use some form of
+object-relational mapping (ORM) technology to create objects
+associated with tables in a relational database. Matt Trout's
+L<DBIx::Class|DBIx::Class> (abbreviated as "DBIC") has rapidly emerged
+as the Perl-based ORM technology of choice. Most new Catalyst
+applications rely on DBIx::Class, as will this tutorial.
+
+Although DBIx::Class has included support for a C<create=dynamic> mode
+to automatically read the database structure every time the
+application starts, it's use is no longer recommended. While it can
+make for "flashy" demos, the use of the C<create=static> mode we use
+below can be implemented just as quickly and provides many advantages
+(such as the ability to add your own methods to the overall DBIC
+framework, a technique that we see in Chapter 4).
+
+
+=head2 Make Sure You Have a Recent Version of the DBIx::Class Model
+
+First, let's be sure we have a recent version of the DBIC helper,
+L<Catalyst::Model::DBIC::Schema|Catalyst::Model::DBIC::Schema>, by
+running this command:
+
+ $ perl -MCatalyst::Model::DBIC::Schema -e \
+ 'print "$Catalyst::Model::DBIC::Schema::VERSION\n"'
+ 0.23
+(please note that the '\' above is a line continuation marker and
+should NOT be included as part of the command)
-=head2 Create a Dynamic DBIC Model
+If you don't have version 0.23 or higher, please run this command
+to install it directly from CPAN:
+
+ $ sudo cpan Catalyst::Model::DBIC::Schema
-Use the C<create=dynamic> model helper option to build a model that
-dynamically reads your database structure every time the application
-starts:
+And re-run the version print command to verify that you are now at
+0.23 or higher.
+
+
+=head2 Create Static DBIx::Class Schema Files
+
+Before you continue, make sure your C<myapp.db> database file is in
+the application's topmost directory. Now use the model helper with
+the C<create=static> option to read the database with
+L<DBIx::Class::Schema::Loader|DBIx::Class::Schema::Loader> and
+automatically build the required files for us:
$ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
- create=dynamic dbi:SQLite:myapp.db
+ create=static components=TimeStamp dbi:SQLite:myapp.db
exists "/home/me/MyApp/script/../lib/MyApp/Model"
exists "/home/me/MyApp/script/../t"
- exists "/home/me/MyApp/script/../lib/MyApp"
- created "/home/me/MyApp/script/../lib/MyApp/Schema.pm"
+ Dumping manual schema for MyApp::Schema to directory /home/me/MyApp/script/../lib ...
+ Schema dump completed.
created "/home/me/MyApp/script/../lib/MyApp/Model/DB.pm"
created "/home/me/MyApp/script/../t/model_DB.t"
+(please note that the '\' above is a line continuation marker and
+should NOT be included as part of the command)
The C<script/myapp_create.pl> command breaks down like this:
=item *
-Because we specified C<create=dynamic> to the helper, it use
+C<create=static> causes
L<DBIx::Class::Schema::Loader|DBIx::Class::Schema::Loader> to
-dynamically load the schema information from the database every time
-the application starts.
+load the schema as it runs and then write that information out
+into files.
+
+=item *
+
+C<components=TimeStamp> causes the help to include the
+L<DBIx::Class::TimeStamp|DBIx::Class::TimeStamp> DBIC component.
=item *
=back
-B<NOTE:> Although the C<create=dynamic> option to the DBIC helper
-makes for a nifty demonstration, is only really suitable for very
-small applications. After this demonstration, you should almost always
-use the C<create=static> option that we will switch to below.
+If you look in the C<lib/MyApp/Schema.pm> file, you will find that it
+only contains a call to the C<load_namespaces> method. You will also
+find that C<lib/MyApp> contains a C<Schema> subdirectory, which then
+has a subdirectory called "Result". This "Result" subdirectory then
+has files named according to each of the tables in our simple database
+(C<Author.pm>, C<BookAuthor.pm>, and C<Book.pm>). These three
+files are called "Result Classes" in DBIx::Class nomenclature. Although the
+Result Class files are named after tables in our database, the classes
+correspond to the I<row-level data> that is returned by DBIC (more on
+this later, especially in
+L<Catalyst::Manual::Tutorial::BasicCRUD/EXPLORING THE POWER OF DBIC>).
+
+The idea with the Result Source files created under
+C<lib/MyApp/Schema/Result> by the C<create=static> option is to only
+edit the files below the C<# DO NOT MODIFY THIS OR ANYTHING ABOVE!>
+warning. If you place all of your changes below that point in the
+file, you can regenerate the automatically created information at the
+top of each file should your database structure get updated.
+
+Also note the "flow" of the model information across the various files
+and directories. Catalyst will initially load the model from
+C<lib/MyApp/Model/DB.pm>. This file contains a reference to
+C<lib/MyApp/Schema.pm>, so that file is loaded next. Finally, the
+call to C<load_namespaces> in C<Schema.pm> will load each of the
+"Result Class" files from the C<lib/MyApp/Schema/Result> subdirectory.
+The final outcome is that Catalyst will dynamically create three
+table-specific Catalyst models every time the application starts (you
+can see these three model files listed in the debug output generated
+when you launch the application).
+
+B<NOTE:> Older versions of
+L<Catalyst::Model::DBIC::Schema|Catalyst::Model::DBIC::Schema> use the
+deprecated DBIx::Class C<load_classes> technique instead of the newer
+C<load_namspaces>. For new applications, please try to use
+C<load_namespaces> since it more easily supports a very useful DBIC
+technique called "ResultSet Classes." If you need to convert an
+existing application from "load_classes" to "load_namespaces," you can
+use this process to automate the migration (but first make sure you
+have v0.23 C<Catalyst::Model::DBIC::Schema> as discussed above):
+
+ $ # First delete the existing schema file to disable "compatibility" mode
+ $ rm lib/MyApp/Schema.pm
+ $
+ $ # Then re-run the helper to build the files for "load_namespaces"
+ $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
+ create=static components=TimeStamp dbi:SQLite:myapp.db
+ $
+ $ # Note that the '\' above is a line continuation marker and
+ $ # should NOT be included as part of the command
+
+ $
+ $ # Now convert the existing files over
+ $ cd lib/MyApp/Schema
+ $ perl -MIO::All -e 'for (@ARGV) { my $s < io($_); $s =~ s/.*\n\# You can replace.*?\n//s;
+ $s =~ s/'MyApp::Schema::/'MyApp::Schema::Result::/g; my $d < io("Result/$_");
+ $d =~ s/1;\n?//; "$d$s" > io("Result/$_"); }' *.pm
+ $ cd ../../..
+ $
+ $ # And finally delete the old files
+ $ rm lib/MyApp/Schema/*.pm
+
+The "C<perl -MIO::ALL ...>" script will copy all the customized
+relationship (and other) information below "C<# DO NOT MODIFY>" line
+from the old files in C<lib/MyApp/Schema> to the new files in
+C<lib/MyApp/Schema/Result> (we will be starting to add some
+"customized relationship information in the section below).
=head1 ENABLE THE MODEL IN THE CONTROLLER
Open C<lib/MyApp/Controller/Books.pm> and un-comment the model code we
left disabled earlier so that your version matches the following (un-
-comment the line containing C<[$c-E<gt>model('DB::Books')-E<gt>all]>
+comment the line containing C<[$c-E<gt>model('DB::Book')-E<gt>all]>
and delete the next 2 lines):
=head2 list
# Retrieve all of the book records as book model objects and store in the
# stash where they can be accessed by the TT template
- $c->stash->{books} = [$c->model('DB::Books')->all];
+ $c->stash->{books} = [$c->model('DB::Book')->all];
# Set the TT template to use. You will almost always want to do this
# in your action methods (action methods respond to user input in
$c->stash->{template} = 'books/list.tt2';
}
-B<TIP>: You may see the C<$c-E<gt>model('DB::Books')> un-commented
-above written as C<$c-E<gt>model('DB')-E<gt>resultset('Books')>. The
+B<TIP>: You may see the C<$c-E<gt>model('DB::Book')> un-commented
+above written as C<$c-E<gt>model('DB')-E<gt>resultset('Book')>. The
two are equivalent. Either way, C<$c-E<gt>model> returns a
L<DBIx::Class::ResultSet|DBIx::Class::ResultSet> which handles queries
against the database and iterating over the set of results that is
things like filtering and sorting the results. For example, the
following could be used to sort the results by descending title:
- $c->model('DB::Books')->search({}, {order_by => 'title DESC'});
+ $c->model('DB::Book')->search({}, {order_by => 'title DESC'});
Some other examples are provided in
L<DBIx::Class::Manual::Cookbook/Complex WHERE clauses>, with
[debug] Statistics enabled
[debug] Loaded plugins:
.----------------------------------------------------------------------------.
- | Catalyst::Plugin::ConfigLoader 0.20 |
- | Catalyst::Plugin::StackTrace 0.08 |
- | Catalyst::Plugin::Static::Simple 0.20 |
+ | Catalyst::Plugin::ConfigLoader 0.23 |
+ | Catalyst::Plugin::StackTrace 0.10 |
+ | Catalyst::Plugin::Static::Simple 0.21 |
'----------------------------------------------------------------------------'
[debug] Loaded dispatcher "Catalyst::Dispatcher"
| MyApp::Controller::Books | instance |
| MyApp::Controller::Root | instance |
| MyApp::Model::DB | instance |
- | MyApp::Model::DB::Authors | class |
- | MyApp::Model::DB::BookAuthors | class |
- | MyApp::Model::DB::Books | class |
+ | MyApp::Model::DB::Author | class |
+ | MyApp::Model::DB::Book | class |
+ | MyApp::Model::DB::BookAuthor | class |
| MyApp::View::TT | instance |
'-----------------------------------------------------------------+----------'
| /books/list | /books/list |
'-------------------------------------+--------------------------------------'
- [info] MyApp powered by Catalyst 5.71000
+ [info] MyApp powered by Catalyst 5.80003
You can connect to your server at http://debian:3000
B<NOTE:> Be sure you run the C<script/myapp_server.pl> command from
Catalyst::Model::DBIC::Schema dynamically created three model classes,
one to represent each of the three tables in our database
-(C<MyApp::Model::DB::Authors>, C<MyApp::Model::DB::BookAuthors>,
-and C<MyApp::Model::DB::Books>).
+(C<MyApp::Model::DB::Author>, C<MyApp::Model::DB::BookAuthor>,
+and C<MyApp::Model::DB::Book>).
=item *
The rating for each book should appear on each row, but the "Author(s)"
column will still be blank (we will fill that in later).
-Also notice in the output of the C<script/myapp_server.pl> that DBIC
-used the following SQL to retrieve the data:
+Also notice in the output of the C<script/myapp_server.pl> that
+DBIx::Class used the following SQL to retrieve the data:
SELECT me.id, me.title, me.rating FROM books me
template -- the wrapper will provide the overall feel of the page.
-=head1 A STATIC DATABASE MODEL WITH DBIx::Class
-
-First, let's be sure we have a recent version of the DBIC helper,
-L<Catalyst::Model::DBIC::Schema|Catalyst::Model::DBIC::Schema>, by
-running this command:
-
- $ perl -MCatalyst::Model::DBIC::Schema -e \
- 'print "$Catalyst::Model::DBIC::Schema::VERSION\n"'
- 0.23
-
-If you don't have version 0.23 or higher, please run this command
-to install it directly from CPAN:
-
- $ sudo cpan Catalyst::Model::DBIC::Schema
-
-And re-run the version print command to verify that you are now at
-0.23 or higher.
-
-
-=head2 Create Static DBIC Schema Files
-
-Unlike the previous DBIC section where we had C<create=dynamic>
-automatically discover the structure of the database every time the
-application started, here we will use static schema files for more
-control. This is typical of most "real world" applications.
-
-One option would be to manually create a separate schema file for each
-table in the database. However, let's use the same
-L<DBIx::Class::Schema::Loader|DBIx::Class::Schema::Loader> we used
-earlier with C<create=dynamic> to build the static files for us.
-First, let's remove the schema file created earlier:
-
- $ rm lib/MyApp/Schema.pm
-
-Now regenerate the schema using the C<create=static> option:
-
- $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
- create=static components=TimeStamp dbi:SQLite:myapp.db
- exists "/home/me/MyApp/script/../lib/MyApp/Model"
- exists "/home/me/MyApp/script/../t"
- Dumping manual schema for MyApp::Schema to directory /home/me/MyApp/script/../lib ...
- Schema dump completed.
- exists "/home/me/MyApp/script/../lib/MyApp/Model/DB.pm"
-
-We could have also deleted C<lib/MyApp/Model/DB.pm>, but it would
-have regenerated the same file (note the C<exists> in the output above).
-If you take a look at C<lib/MyApp/Model/DB.pm>, it simply contains
-a reference to the actual schema file in C<lib/MyApp/Schema.pm>
-along with the database connect string.
-
-If you look in the C<lib/MyApp/Schema.pm> file, you will find that it
-is no longer using
-L<DBIx::Class::Schema::Loader|DBIx::Class::Schema::Loader> as its base
-class (L<DBIx::Class::Schema::Loader|DBIx::Class::Schema::Loader> is
-only being used by the helper to load the schema once and then create
-the static files for us) and C<Schema.pm> only contains a call to the
-C<load_namespaces> method. You will also find that C<lib/MyApp>
-contains a C<Schema> subdirectory, which then has a subdirectory
-called "Result". This "Result" subdirectory then has files named
-according to each of the tables in our simple database (C<Authors.pm>,
-C<BookAuthors.pm>, and C<Books.pm>). These three files are called
-"Result Classes" in DBIC nomenclature. Although the Result Class files
-are named after tables in our database, the classes correspond to the
-I<row-level data> that is returned by DBIC (more on this later,
-especially in
-L<Catalyst::Manual::Tutorial::BasicCRUD/EXPLORING THE POWER OF DBIC>).
-
-The idea with the Result Source files created under
-C<lib/MyApp/Schema/Result> by the C<create=static> option is to only
-edit the files below the C<# DO NOT MODIFY THIS OR ANYTHING ABOVE!>
-warning. If you place all of your changes below that point in the
-file, you can regenerate the automatically created information at the
-top of each file should your database structure get updated.
-
-Also note the "flow" of the model information across the various files
-and directories. Catalyst will initially load the model from
-C<lib/MyApp/Model/DB.pm>. This file contains a reference to
-C<lib/MyApp/Schema.pm>, so that file is loaded next. Finally, the
-call to C<load_namespaces> in C<Schema.pm> will load each of the
-"Result Class" files from the C<lib/MyApp/Schema/Result> subdirectory.
-The final outcome is that Catalyst will dynamically create three
-table-specific Catalyst models every time the application starts (you
-can see these three model files listed in the debug output generated
-when you launch the application).
-
-B<NOTE:> Older versions of
-L<Catalyst::Model::DBIC::Schema|Catalyst::Model::DBIC::Schema> use the
-deprecated DBIC C<load_classes> technique instead of the newer
-C<load_namspaces>. For new applications, please try to use
-C<load_namespaces> since it more easily supports a very useful DBIC
-technique called "ResultSet Classes." If you need to convert an
-existing application from "load_classes" to "load_namespaces," you can
-use this process to automate the migration (but first make sure you
-have v0.23 C<Catalyst::Model::DBIC::Schema> as discussed above):
-
- $ # First delete the existing schema file to disable "compatibility" mode
- $ rm lib/MyApp/Schema.pm
- $
- $ # Then re-run the helper to build the files for "load_namespaces"
- $ script/myapp_create.pl model DB DBIC::Schema MyApp::Schema \
- create=static components=TimeStamp dbi:SQLite:myapp.db
- $
- $ # Now convert the existing files over
- $ cd lib/MyApp/Schema
- $ perl -MIO::All -e 'for (@ARGV) { my $s < io($_); $s =~ s/.*\n\# You can replace.*?\n//s;
- $s =~ s/'MyApp::Schema::/'MyApp::Schema::Result::/g; my $d < io("Result/$_");
- $d =~ s/1;\n?//; "$d$s" > io("Result/$_"); }' *.pm
- $ cd ../../..
- $
- $ # And finally delete the old files
- $ rm lib/MyApp/Schema/*.pm
-
-The "C<perl -MIO::ALL ...>" script will copy all the customized
-relationship (and other) information below "C<# DO NOT MODIFY>" line
-from the old files in C<lib/MyApp/Schema> to the new files in
-C<lib/MyApp/Schema/Result> (we will be starting to add some
-"customized relationship information in the section below).
-
-
-=head2 Updating the Generated DBIC Result Class Files
+=head2 Updating the Generated DBIx::Class Result Class Files
Let's manually add some relationship information to the auto-generated
Result Class files. (Note: if you are using a database other than
SQLite, such as PostgreSQL, then the relationship could have been
automatically placed in the Result Class files. If so, you can skip
-this step.) First edit C<lib/MyApp/Schema/Result/Books.pm> and add the
+this step.) First edit C<lib/MyApp/Schema/Result/Book.pm> and add the
following text below the C<# You can replace this text...> comment:
#
# 1) Name of relationship, DBIC will create accessor with this name
# 2) Name of the model class referenced by this relationship
# 3) Column name in *foreign* table (aka, foreign key in peer table)
- __PACKAGE__->has_many(book_authors => 'MyApp::Schema::Result::BookAuthors', 'book_id');
+ __PACKAGE__->has_many(book_author => 'MyApp::Schema::Result::BookAuthor', 'book_id');
# many_to_many():
# args:
# 2) Name of has_many() relationship this many_to_many() is shortcut for
# 3) Name of belongs_to() relationship in model class of has_many() above
# You must already have the has_many() defined to use a many_to_many().
- __PACKAGE__->many_to_many(authors => 'book_authors', 'author');
+ __PACKAGE__->many_to_many(author => 'book_author', 'author');
B<Note:> Be careful to put this code I<above> the C<1;> at the end of the
a statement that evaluates to C<true>. This is customarily done with
C<1;> on a line by itself.
-C<Important Note:> Although this tutorial uses plural names for both
-the names of the SQL tables and therefore the Result Classes (after
-all, C<Schema::Loader> automatically named the Result Classes from the
-names of the SQL tables it found), DBIC users prefer singular names
-for these items. B<Please try to use singular table and DBIC
-model/Result Class names in your applications.> This tutorial will
-migrate to singular names as soon as possible (patches welcomed).
-B<Note that while singular is preferred for the DBIC model, plural is
-perfectly acceptable for the names of the controller classes.> After
-all, the C<Books.pm> controller operates on multiple books.
-
-This code defines both a C<has_many> and a C<many_to_many> relationship.
-The C<many_to_many> relationship is optional, but it makes it easier to
-map a book to its collection of authors. Without it, we would have to
-"walk" though the C<book_authors> table as in
-C<$book-E<gt>book_authors-E<gt>first-E<gt>author-E<gt>last_name>
-(we will see examples on how to use DBIC objects in your code soon,
-but note that because C<$book-E<gt>book_authors> can return multiple
+This code defines both a C<has_many> and a C<many_to_many>
+relationship. The C<many_to_many> relationship is optional, but it
+makes it easier to map a book to its collection of authors. Without
+it, we would have to "walk" though the C<book_author> table as in
+C<$book-E<gt>book_author-E<gt>first-E<gt>author-E<gt>last_name> (we
+will see examples on how to use DBIx::Class objects in your code soon,
+but note that because C<$book-E<gt>book_author> can return multiple
authors, we have to use C<first> to display a single author).
-C<many_to_many> allows us to use the shorter
-C<$book-E<gt>authors-E<gt>first-E<gt>last_name>.
-Note that you cannot define a C<many_to_many> relationship without
-also having the C<has_many> relationship in place.
+C<many_to_many> allows us to use the shorter C<$book-E<gt>author-
+E<gt>first-E<gt>last_name>. Note that you cannot define a
+C<many_to_many> relationship without also having the C<has_many>
+relationship in place.
-Then edit C<lib/MyApp/Schema/Result/Authors.pm> and add relationship
+Then edit C<lib/MyApp/Schema/Result/Author.pm> and add relationship
information as follows (again, be careful to put in above the C<1;> but
below the C<# DO NOT MODIFY THIS OR ANYTHING ABOVE!> comment):
# 1) Name of relationship, DBIC will create an accessor with this name
# 2) Name of the model class referenced by this relationship
# 3) Column name in *foreign* table (aka, foreign key in peer table)
- __PACKAGE__->has_many(book_author => 'MyApp::Schema::Result::BookAuthors', 'author_id');
+ __PACKAGE__->has_many(book_author => 'MyApp::Schema::Result::BookAuthor', 'author_id');
# many_to_many():
# args:
# 2) Name of has_many() relationship this many_to_many() is shortcut for
# 3) Name of belongs_to() relationship in model class of has_many() above
# You must already have the has_many() defined to use a many_to_many().
- __PACKAGE__->many_to_many(books => 'book_author', 'book');
+ __PACKAGE__->many_to_many(book => 'book_author', 'book');
Finally, do the same for the "join table,"
-C<lib/MyApp/Schema/Result/BookAuthors.pm>:
+C<lib/MyApp/Schema/Result/BookAuthor.pm>:
#
# Set relationships:
# 1) Name of relationship, DBIC will create accessor with this name
# 2) Name of the model class referenced by this relationship
# 3) Column name in *this* table
- __PACKAGE__->belongs_to(book => 'MyApp::Schema::Result::Books', 'book_id');
+ __PACKAGE__->belongs_to(book => 'MyApp::Schema::Result::Book', 'book_id');
# belongs_to():
# args:
# 1) Name of relationship, DBIC will create accessor with this name
# 2) Name of the model class referenced by this relationship
# 3) Column name in *this* table
- __PACKAGE__->belongs_to(author => 'MyApp::Schema::Result::Authors', 'author_id');
+ __PACKAGE__->belongs_to(author => 'MyApp::Schema::Result::Author', 'author_id');
=head2 Run The Application
Let's add a new column to our book list page that takes advantage of
the relationship information we manually added to our schema files in
-the previous section. Edit C<root/src/books/list.tt2> and add the
-following code below the existing table cell that contains
-C<book.rating> (IOW, add a new table cell below the existing two
-C<E<lt>tdE<gt>> tags but above the closing C<E<lt>/trE<gt>> and
-C<E<lt>/tableE<gt>> tags):
+the previous section. Edit C<root/src/books/list.tt2> and replace
+the "empty" table cell "<td></td>" with the following:
...
<td>
If you are still running the development server with C<DBIC_TRACE>
enabled, you should also now see five more C<SELECT> statements in the
debug output (one for each book as the authors are being retrieved by
-DBIC):
+DBIx::Class):
SELECT me.id, me.title, me.rating FROM books me:
- SELECT author.id, author.first_name, author.last_name FROM book_authors me
- JOIN authors author ON ( author.id = me.author_id ) WHERE ( me.book_id = ? ): '1'
- SELECT author.id, author.first_name, author.last_name FROM book_authors me
- JOIN authors author ON ( author.id = me.author_id ) WHERE ( me.book_id = ? ): '2'
- SELECT author.id, author.first_name, author.last_name FROM book_authors me
- JOIN authors author ON ( author.id = me.author_id ) WHERE ( me.book_id = ? ): '3'
- SELECT author.id, author.first_name, author.last_name FROM book_authors me
- JOIN authors author ON ( author.id = me.author_id ) WHERE ( me.book_id = ? ): '4'
- SELECT author.id, author.first_name, author.last_name FROM book_authors me
- JOIN authors author ON ( author.id = me.author_id ) WHERE ( me.book_id = ? ): '5'
+ SELECT author.id, author.first_name, author.last_name FROM book_author me
+ JOIN author author ON ( author.id = me.author_id ) WHERE ( me.book_id = ? ): '1'
+ SELECT author.id, author.first_name, author.last_name FROM book_author me
+ JOIN author author ON ( author.id = me.author_id ) WHERE ( me.book_id = ? ): '2'
+ SELECT author.id, author.first_name, author.last_name FROM book_author me
+ JOIN author author ON ( author.id = me.author_id ) WHERE ( me.book_id = ? ): '3'
+ SELECT author.id, author.first_name, author.last_name FROM book_author me
+ JOIN author author ON ( author.id = me.author_id ) WHERE ( me.book_id = ? ): '4'
+ SELECT author.id, author.first_name, author.last_name FROM book_author me
+ JOIN author author ON ( author.id = me.author_id ) WHERE ( me.book_id = ? ): '5'
Also note in C<root/src/books/list.tt2> that we are using "| html", a
type of TT filter, to escape characters such as E<lt> and E<gt> to <
# Retrieve all of the book records as book model objects and store in the
# stash where they can be accessed by the TT template
- $c->stash->{books} = [$c->model('DB::Books')->all];
+ $c->stash->{books} = [$c->model('DB::Book')->all];
# Set the TT template to use. You will almost always want to do this
# in your action methods (actions methods respond to user input in
the C<$c-E<gt>detach> mechanisms (these are discussed in Chapter 2 and
Chapter 9 of the Tutorial).
+B<IMPORTANT:> Make sure that you do NOT skip the following section
+before continuing to the next chapter 4 Basic CRUD.
=head2 Return To A Manually Specified Template
projects / catagits/Catalyst-Manual.git / blobdiff