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64 <h1>DBIx::Class Introduction</h1>
65 <h2>YAPC::NA 2010</h2>
69 <div class="presentation">
72 <h1>DBIX::Class (aka DBIC)</h1>
73 <h3>for (advanced) beginners</h3>
78 <h4>Originally Leo Lapworth @ LPW 2009</h4>
79 <h4>Amiri Barksdale</h4>
80 <h4>Justin D. Hunter</h4>
81 <h4>Arthur Axel "fREW" Schmidt</h4>
85 <h1>What's up guys?</h1>
88 <li>How many people have used any ORM?<ul>
98 <li>(N)Hibernate?</li>
106 <p>The purpose of this talk is to show you as many features of
107 DBIx::Class in 40 minutes so that when you need to do something with
108 it later you will know what's possible</p>
109 <ul class="incremental">
110 <li>Note: links in slides are so you can find docs for what I'm talking about later</li>
115 <h1>DBIx::Class?</h1>
117 <li>ORM (object relational mapper)</li>
118 <li>SQL <-> OO (using objects instead of SQL)</li>
119 <li>There are many ORMs, DBIx::Class just happens to be the best in Perl (personal opinion)</li>
125 <p>These are reasons that are not technical or inherent to
126 the code of DBIC, but are totally awesome things about it.</p>
130 <h1>Large Community</h1>
131 <p>Currently there are 88 people listed as contributors to DBIC. That
132 ranges from documentation help, to test help, to added features,
133 to entire database support.</p>
137 <h1>Active Community</h1>
138 <p>Currently (June 9, 2010) 6 active branches (commited to in the last two weeks) in git. Last release (0.08122) had 14 new features, and 16 bug fixes. Of course that <a href="http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=dbsrgits/DBIx-Class.git;a=blob;f=Changes">ebbs and flows</a>.</p>
142 <h1>Responsive Community</h1>
143 <ul class="incremental">
144 <li>needed MSSQL order-by support, they helped me add support</li>
145 <li>generally very welcoming of people willing to help</li>
151 <p>These are things that are in most other ORMs, but are still reasons
152 to use DBIC over raw SQL.</p>
157 <p>The vast majority of code should run on all databases without needing tweaking</p>
162 <ul class="incremental">
163 <li><strong>C</strong> - Create</li>
164 <li><strong>R</strong> - Read</li>
165 <li><strong>U</strong> - Update</li>
166 <li><strong>D</strong> - Delete</li>
172 <pre>my $sth = $dbh->prepare('
179 'A book title', $author_id
184 <h1>DBIC: Create</h1>
185 <pre>my $book = $book_rs-><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#create">create</a>({
186 title => 'A book title',
187 author_id => $author_id,
189 <ul class="incremental">
190 <li>No need to pair placeholders and values</li>
191 <li>Automatically gets autoincremented id for you</li>
192 <li>Transparrently uses INSERT ... RETURNING for databases that support it</li>
198 <pre>my $sth = $dbh->prepare('
200 authors.name as author_name
202 WHERE books.author = authors.id
208 <pre>while( my $book = $sth->fetchrow_hashref() ) {
212 . $book->{author_name}
219 <pre>my $book = $book_rs-><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#find">find</a>($book_id);
221 my $book = $book_rs-><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#search">search</a>({
222 title => 'A book title',
223 }, { rows => 1 })-><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#next">next</a>;
225 my @books = $book_rs->search({
226 author => $author_id,
227 })-><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#all">all</a>;</pre>
228 <ul class="incremental">
235 <pre>while( my $book = $books_rs->next ) {
239 . $book->author->name
246 <pre>my $update = $dbh->prepare('
253 'New title',<strong>$book_id</strong>
258 <h1>DBIC: Update</h1>
259 <pre>$book-><a href="http://search.cpan.org/perldoc?DBIx::Class::Row#update">update</a>({
260 title => 'New title',
262 <ul class="incremental">
269 <pre>my $delete = $dbh->prepare('
274 $delete->execute(<strong>$book_id</strong>);</pre>
278 <h1>DBIC: Delete</h1>
279 <pre>$book-><a href="http://search.cpan.org/perldoc?DBIx::Class::Row#delete">delete</a>;</pre>
283 <h1>OO Overidability</h1>
284 <ul class="incremental">
285 <li>Override new if you want to do validation</li>
286 <li>Override delete if you want to disable deletion</li>
287 <li>and on and on</li>
290 <p>I got yelled at about this before by people, so
291 we don't get EVERYTHING from OO, but we do get a lot
297 <h1>Convenience Methods</h1>
298 <ul class="incremental">
299 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#find_or_create">find_or_create</a></li>
300 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#update_or_create">update_or_create</a></li>
305 <h1>Non-column methods</h1>
306 <p>Need a method to get a user's gravatar URL? Add a
307 gravatar_url method to their Result class</p>
311 <h1>RELATIONSHIPS</h1>
312 <ul class="incremental">
313 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Relationship#belongs_to">belongs_to</a></li>
314 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Relationship#has_many">has_many</a></li>
315 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Relationship#might_have">might_have</a></li>
316 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Relationship#has_one">has_one</a></li>
317 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Relationship#many_to_many">many_to_many</a> (technically not a relationship)</li>
318 <li>SET AND FORGET</li>
323 <h1>DBIx::Class Specific Features</h1>
324 <p>These things may be in other ORM's, but they are very specific, so doubtful</p>
330 <pre>my $schema = Foo::Schema->connect(
333 $schema-><a href="http://search.cpan.org/perldoc?DBIx::Class::Schema#deploy">deploy</a>
335 <p>See also: <a href="http://search.cpan.org/perldoc?DBIx::Class::DeploymentHandler">DBIx::Class::DeploymentHandler</a></p>
339 <h1>Schema::Loader</h1>
341 <pre>package Foo::Schema;
342 use strict; use warnings;
343 use base '<a href="http://search.cpan.org/perldoc?DBIx::Class::Schema::Loader">DBIx::Class::Schema::Loader</a>';
344 __PACKAGE__-><a href="http://search.cpan.org/perldoc?DBIx::Class::Schema::Loader::Base#CONSTRUCTOR_OPTIONS">loader_options</a>({
346 debug => $ENV{DBIC_TRACE},
352 my $schema = Foo::Schema->connect(
360 <p>Made for inserting lots of rows very quicky into database</p>
361 <pre>$schema-><a href="http://search.cpan.org/perldoc?DBIx::Class::Schema#populate">populate</a>([ Users =>
362 [qw( username password )],
363 [qw( frew >=4char$ )],
368 <ul class="incremental">
369 <li>I use this to <a href="http://blog.afoolishmanifesto.com/archives/1255">export our whole (200M~) db to SQLite</a></li>
375 <p>Create an object and all of it's related objects all at once</p>
376 <pre>$schema->resultset('Author')-><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#create">create</a>({
377 name => 'Stephen King',
378 books => [{ title => 'The Dark Tower' }],
380 street => '123 Turtle Back Lane',
381 state => { abbreviation => 'ME' },
382 city => { name => 'Lowell' },
388 <li>books is a has_many</li>
389 <li>address is a belongs_to which in turn belongs to state and city each</li>
390 <li>for this to work right state and city must mark abbreviation and name as unique</li>
397 <p>DBIx::Class helped pioneer fast MI in Perl 5 with Class::C3, so it is made
398 to allow extensions to nearly every part of it.</p>
402 <h1>Extensible: DBIC::Helpers</h1>
403 <ul class="incremental">
404 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Helper::ResultSet::IgnoreWantarray">DBIC::Helper::ResultSet::IgnoreWantarray</a></li>
405 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Helper::ResultSet::Random">DBIC::Helper::ResultSet::Random</a></li>
406 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Helper::ResultSet::SetOperations">DBIC::Helper::ResultSet::SetOperations</a></li>
407 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Helper::ResultSet::JoinTable">DBIC::Helper::Row::JoinTable</a></li>
408 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Helper::ResultSet::NumifyGet">DBIC::Helper::Row::NumifyGet</a></li>
409 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Helper::ResultSet::SubClass">DBIC::Helper::Row::SubClass</a></li>
410 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Helper::ResultSet::ToJSON">DBIC::Helper::Row::ToJSON</a></li>
415 <h1>Extensible: <a href="http://search.cpan.org/perldoc?DBIx::Class::TimeStamp">DBIC::TimeStamp</a></h1>
416 <ul class="incremental">
418 <li>set_on_create</li>
419 <li>set_on_update</li>
424 <h1>Extensible: Kioku</h1>
425 <ul class="incremental">
426 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::Schema::KiokuDB">DBIx::Class::Schema::KiokuDB</a></li>
427 <li>Kioku is the new hotness</li>
428 <li>Mix RDBMS with Object DB</li>
429 <li>beta ( == sexy )</li>
434 <h1><a href="http://search.cpan.org/perldoc?SQL::Abstract">SQL::Abstract</a></h1>
435 <pre>my $resultset = $book_rs->search({
436 name => { -like => "%$nick%" },
438 <ul class="incremental">
439 <li>(kinda) introspectible</li>
440 <li>Prettier than SQL</li>
445 <h1>Result vs ResultSet</h1>
446 <ul class="incremental">
447 <li>Result == Row</li>
448 <li>ResultSet == Query Plan<ul class="incremental">
449 <li>Internal Join Optimizer for all DB's (!!!)</li>
451 <li>(less important but...)</li>
452 <li>ResultSource == Table</li>
453 <li>Storage == Database</li>
458 <h1><a href="http://search.cpan.org/perldoc?DBIx::Class::Manual::Cookbook#Predefined_searches">ResultSet methods</a></h1>
459 <pre>package MyApp::Schema::ResultSet::Book;
460 use base 'DBIx::Class::ResultSet';
464 $self->current_source_alias .
465 '.rating' => { '>=' => 4 },
471 $self->current_source_alias .
472 '.price' => { '<=' => 5}
481 <h1>ResultSet method notes</h1>
482 <ul class="incremental">
483 <li>All searches should be ResultSet methods</li>
484 <li>Name has obvious meaning</li>
485 <li><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#current_source_alias">current_source_alias</a> helps things to work no matter what</li>
490 <h1>ResultSet method in Action</h1>
491 <pre>$schema->resultset('Book')->good</pre>
495 <h1>ResultSet Chaining</h1>
496 <pre>$schema->resultset('Book')
504 <h1>search_related</h1>
505 <pre>my $score = $schema->resultset('User')
506 ->search({'me.userid' => 'frew'})
507 -><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#related_resultset">related_resultset</a>('access')
508 ->related_resultset('mgmt')
509 ->related_resultset('orders')
511 -><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#search_related">search_related</a>( shops => {
512 'shops.datecompleted' => {
513 -between => ['2009-10-01','2009-10-08']
516 ->related_resultset('rpt_score')
517 -><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#get_column">get_column</a>('raw_scores')
523 <h1>bonus rel methods</h1>
524 <pre>my $book = $author-><a href="http://search.cpan.org/perldoc?DBIx::Class::Relationship::Base#create_related">create_related</a>(
525 <strong>books</strong> => {
526 title => 'Another Discworld book',
530 my $book2 = $pratchett-><a href="http://search.cpan.org/perldoc?DBIx::Class::Relationship::Base#add_to_$rel">add_to_<strong>books</strong></a>({
531 title => 'MOAR Discworld book',
533 <ul class="incremental">
534 <li>Automaticaly fills in foreign key for you</li>
539 <h1>Excellent Transaction Support</h1>
540 <pre>$schema-><a href="http://search.cpan.org/perldoc?DBIx::Class::Schema#txn_do">txn_do</a>(sub {
544 my $guard = $schema-><a href="http://search.cpan.org/perldoc?DBIx::Class::Schema#txn_scope_guard">txn_scope_guard</a>;
548 $schema-><a href="http://search.cpan.org/perldoc?DBIx::Class::Schema#txn_begin">txn_begin</a>; # <-- low level
550 $schema-><a href="http://search.cpan.org/perldoc?DBIx::Class::Schema#txn_commit">txn_commit</a>;
555 <h1>InflateColumn</h1>
556 <pre>package Foo::Schema::Result::Book;
557 use base 'DBIx::Class::Core';
558 use DateTime::Format::MySQL;
560 __PACKAGE__->load_components('<a href="http://search.cpan.org/perldoc?DBIx::Class::InflateColumn">InflateColumn</a>');
561 __PACKAGE__-><strong><a href="http://search.cpan.org/perldoc?DBIx::Class::InflateColumn#inflate_column">inflate_column</a></strong>(
562 <strong>date_published</strong> => {
564 DateTime::Format::MySQL->parse_date(
568 deflate => sub { shift->ymd },
571 # Automatic see: DBIC::InflateColumn::DateTime</pre>
575 <h1>InflateColumn: deflation</h1>
576 <pre>$book->date_published(DateTime->now);
577 $book->update;</pre>
581 <h1>InflateColumn: inflation</h1>
582 <pre>say $book->date_published->month_abbr;</pre>
584 <strong><em>Nov</em></strong>
588 <h1>FilterColumn</h1>
589 <pre>package Foo::Schema::Result::Book;
590 use base 'DBIx::Class::Core';
592 __PACKAGE__->load_components('<a href="http://search.cpan.org/perldoc?DBIx::Class::FilterColumn">FilterColumn</a>');
594 __PACKAGE__-><strong><a href="http://search.cpan.org/perldoc?DBIx::Class::FilterColumn#filter_column">filter_column</a></strong>(
595 <strong>length</strong> => {
596 to_storage => 'to_metric',
597 from_storage => 'to_imperial',
601 sub to_metric { $_[1] * .305 }
602 sub to_imperial { $_[1] * 3.28 }
606 <h1><a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSetColumn">ResultSetColumn</a></h1>
607 <pre>my $rsc = $schema->resultset('Book')
608 ->get_column('price');
617 <pre>my @res = $rs->search({}, {
618 <a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#select">select</a> => [
624 <a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#as">as</a> => [
625 qw(price genre max_price avg_price)
627 <a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#group_by">group_by</a> => [qw(price genre)],
630 say $_->price . ' ' . $_->genre;
631 say $_->get_column('max_price');
632 say $_->get_column('min_price');
637 <h1>Aggregates Notes</h1>
638 <ul class="incremental">
639 <li>Careful, get_column can basicaly mean THREE things</li>
640 <li>private for get what you should use an accessor for</li>
641 <li>public for what there is no accessor for</li>
642 <li>public for get resultset column (prev slide)</li>
648 <pre>$rs->search({}, {
649 <a href="http://search.cpan.org/perldoc?DBIx::Class::ResultSet#result_class">result_class</a> =>
650 '<a href="http://search.cpan.org/perldoc?DBIx::Class::ResultClass::HashRefInflator">DBIx::Class::ResultClass::HashRefInflator</a>',
652 <ul class="incremental">
653 <li>Easy on memory</li>
655 <li>Great for quick debugging</li>
656 <li>Great for performance tuning (we went from 2m to < 3s)</li>
661 <h1><a href="http://search.cpan.org/perldoc?DBIx::Class::Manual::Cookbook#Subqueries">Subquery</a> Support</h1>
662 <pre>my $inside_query = $schema->resultset('Artist')
664 name => [ 'Billy Joel', 'Brittany Spears' ],
665 })->get_column('id')->as_query;
667 my $rs = $schema->resultset('CD')->search({
668 artist_id => { -in => $inside_query },
673 <h1><a href="http://search.cpan.org/perldoc?SQL::Abstract#Literal_SQL_with_placeholders_and_bind_values_(subqueries)">Bare SQL w/ Placeholders</a></h1>
674 <pre>$rs->update({
675 # !!! SQL INJECTION VECTOR
676 price => \"price + $inc",
680 price => \['price + ?', [inc => $inc]],