DBIx::Class vs. DBix::DataModel
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The document compares the ORM frameworks DBIx::Class and DBIx::DataModel for defining schemas, retrieving data, and performing joins from a Perl program to a database. It provides code examples for defining schemas and result classes, searching for records, and retrieving single records for each framework. The document also compares aspects of schema definition, data retrieval methods, and SQL generation between the two frameworks.
![DBIDM centralized declarations
use DBIx::DataModel;
DBIx::DataModel->Schema("FPW12::DBIDM")
# class table primary key
# ===== ===== ===========
->Table(qw/Auth auths auth_id /)
->Table(qw/Dist dists dist_id /)
->Table(qw/Mod mods mod_id /)
->Table(qw/Depends depends dist_id mod_id/)
# class role multipl. (optional join keys)
# ===== ==== ======= ====================
->Association([qw/Auth auth 1 auth_id /],
[qw/Dist dists * auth_id /])
->Composition([qw/Dist dist 1 /],
[qw/Mod mods * /])
->Association([qw/Dist dist 1 /],
[qw/Depends depends * /])
->Association([qw/Mod mod 1 /],
[qw/Depends depends * /])
->Association([qw/Dist used_in_dist * depends distrib /],
[qw/Mod prereq_mods * depends mod /])
;](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-13-320.jpg)
![DBIC: Search
Département
Office
use FPW12::DBIC;
my $schema = FPW12::DBIC->connect($data_source);
my @dists = $schema->resultset('Dist')->search(
{dist_name => {-like => 'DBIx%'}},
{columns => [qw/dist_name dist_vers/]},
);
foreach my $dist (@dists) {
printf "%s (%s)n", $dist->dist_name, $dist->dist_vers;
}
29.06.12 - Page 1](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-16-320.jpg)
![DBIDM: Search
Département
Office
use FPW12::DBIDM;
use DBI;
my $datasource = "dbi:SQLite:dbname=../cpandb.sql";
my $dbh = DBI->connect($datasource, "", "",
{RaiseError => 1, AutoCommit => 1});
FPW12::DBIDM->dbh($dbh);
my $dists = FPW12::DBIDM::Dist->select(
-columns => [qw/dist_name dist_vers/],
-where => {dist_name => {-like => 'DBIx%'}},
);
foreach my $dist (@$dists) {
print "$dist->{dist_name} ($dist->{dist_vers})n";
}
29.06.12 - Page 1](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-17-320.jpg)
![SQL::Abstract new()
Département
Office
• special operators
– ex: DBMS-independent fulltext search
# where {field => {-contains => [qw/foo bar/]}
my $sqla = SQL::Abstract->new(special_ops => [
{regex => qr/^contains(:?_all|_any)?$/i,
handler => sub {
my ($self, $field, $op, $arg) = @_;
my $connector = ($op =~ /any$/) ? ' | ' : ' & ';
my @vals = ref $arg ? @$arg : ($arg);
@vals = map { split /s+/ } grep {$_} @vals;
my $sql = sprintf "CONTAINS($field, '%s') > 0",
join $connector, @vals;
return ($sql); # no @bind
}
]);
29.06.12 - Page 1](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-19-320.jpg)
![DBIDM: Polymorphic result
-result_as =>
– 'rows' (default) : arrayref of row objects
– 'firstrow' : a single row object (or undef)
– 'hashref' : hashref keyed by primary keys
– [hashref => @cols] : cascaded hashref
– 'flat_arrayref' : flattened values from each row
– 'statement' : a statement object (iterator)
– 'fast_statement' : statement reusing same memory
– 'sth' : DBI statement handle
– 'sql' : ($sql, @bind_values)
– 'subquery' : ["($sql)", @bind]
don't need method variants : select_hashref(), select_arrayref(), etc.](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-24-320.jpg)
![DBIC: Join
my @dists = $schema->resultset('Dist')->search(
{dist_name => {-like => 'DBIx%'}},
{columns => [qw/dist_name dist_vers/],
join => 'auth',
'+columns' => [{'fullname' => 'auth.fullname'}],
},
);
foreach my $dist (@dists) {
printf "%s (%s) by %sn",
$dist->dist_name, $dist->dist_vers,
$dist->get_column('fullname'); # no accessor meth
}](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-29-320.jpg)
![DBIC: Join with prefetch
my @dists = $schema->resultset('Dist')->search(
{dist_name => {-like => 'DBIx%'}},
{columns => [qw/dist_name dist_vers/],
prefetch => 'auth',
},
);
foreach my $dist (@dists) {
printf "%s (%s) by %sn",
$dist->dist_name, $dist->dist_vers,
$dist->auth->fullname; # already in memory
}](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-30-320.jpg)
![DBIDM: Join
my $rows = FPW12::DBIDM->join(qw/Dist auth/)->select(
-columns => [qw/dist_name dist_vers fullname/],
-where => {dist_name => {-like => 'DBIx%'}},
);
foreach my $row (@$rows) {
print "$row->{dist_name} ($row->{dist_vers}) "
. "by $row->{fullname}n";
}
Dist Auth
DBIDM::Source::Join
new class created on the fly ..::AutoJoin::…](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-31-320.jpg)
![Multiple joins
• DBIC
join => [ { abc => { def => 'ghi' } },
{ jkl => 'mno' },
'pqr' ]
• DBIDM
->join(qw/Root abc def ghi jkl mno pqr/)](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-32-320.jpg)
![DBIDM: Left / inner joins
->Association([qw/Author author 1 /],
[qw/Distribution distribs 0..* /])
# default : LEFT OUTER JOIN
->Composition([qw/Distribution distrib 1 /],
[qw/Module modules 1..* /]);
# default : INNER JOIN
# but defaults can be overridden
My::DB->join([qw/Author <=> distribs/)-> . . .
My::DB->join([qw/Distribution => modules /)-> . . .](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-35-320.jpg)
![DBIDM Statement::refine()
my $stmt = FPW12::DBIDM->join(qw/Dist auth/)->select(
-where => {dist_name => {-like => 'DBIx%'}},
-result_as => 'statement',
);
$stmt->refine(
-columns => [-DISTINCT => 'fullname'],
-where => {dist_vers => { ">" => 0}},
-order_by => 'fullname',
);
say $_->{fullname} while $_ = $stmt->next;](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-52-320.jpg)
![DBIDM Types (inflate/deflate)
# declare a Type
My::DB->Type(Multivalue =>
from_DB => sub {$_[0] = [split /;/, $_[0]] },
to_DB => sub {$_[0] = join ";", @$_[0] },
);
# apply it to some columns in a table
My::DB::Author->metadm->define_column_type(
Multivalue => qw/hobbies languages/,
);](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-58-320.jpg)
![SQL::Abstract::More : extensions
• -columns => [qw/col1|alias1 max(col2)|alias2/]
– SELECT col1 AS alias1, max(col2) AS alias2
• -columns => [-DISTINCT => qw/col1 col2 col3/]
– SELECT DISTINCT col1, col2, col3
• -order_by => [qw/col1 +col2 –col3/]
– SELECT … ORDER BY col1, col2 ASC, col3 DESC
• -for => "update" || "read only"
– SELECT … FOR UPDATE](https://image.slidesharecdn.com/dbicvsdbidm-120629085512-phpapp02/85/DBIx-Class-vs-DBix-DataModel-65-320.jpg)
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DBIx::Class vs. DBix::DataModel
- 1. DBIx::Class Département Office vs. DBIx::DataModel FPW 2012, Strasbourg [email protected] Département Office 29.06.12 - Page 1
- 2. Agenda • Introduction • Schema definition • Data retrieval • Joins • Classes and methods • Resultset/Statement objects • Customization • Conclusion
- 3. Introduction
- 4. ORM layer Perl program Object-Relational Mapper DBI DBD driver Database
- 5. ORM useful for … • dynamic SQL generation – navigation between tables – generate complex SQL queries from Perl datastructures – better than phrasebook or string concatenation • automatic data conversions (inflation / deflation) • transaction encapsulation • data validation • computed fields • caching • expansion of tree data structures coded in the relational model • …
- 6. CPAN ORM Landscape • Discussed here – DBIx::Class (a.k.a. DBIC) – DBIx::DataModel (a.k.a. DBIDM) DISCLAIMER - I'm not an expert of DBIC - I'll try to be neutral in comparisons, but … - Won't cover all topics • Many other – Rose::DB, Jifty::DBI, Fey::ORM, ORM, DBIx::ORM::Declarative, Tangram, Coat::Persistent, ORLite, DBR, DBIx::Sunny, DBIx::Skinny, DBI::Easy, …
- 7. A bit of 2005 history Class::DBI (1999) SQL::Abstract (2001) DBIx::DataModel private (feb.05) Class::DBI::Sweet (29.05.05) - SQL::Abstract Class::DBI::Sweet 0.02 (29.06.05) -prefetch joins DBIx::Class 0.01 (08.08.05) - SQL::Abstract DBIx::Class 0.03 (19.09.05) DBIx::DataModel 0.10 (16.09.05) - prefetch joins
- 8. Some figures • DBIC • DBIDM – thousands of users – a couple of users – dozens of contributors – 1 contributor – 162 files – 31 files – 167 packages – 40 packages – 1042 subs/methods – 175 subs/methods – 16759 lines of Perl – 3098 lines of Perl – 1817 comment lines – 613 comment lines – 19589 lines of POD – 8146 lines of POD – 70 transitive dependencies – 54 transitive dependencies
- 9. Our example : CPAN model straight from CPAN::SQLite Author 1 * 1 contains ► 1..* Distribution Module * * depends_on ►
- 10. Département Office Schema definition 29.06.12 - Page 1
- 11. DBIC Schema class Département Office use utf8; package FPW12::DBIC; use strict; use warnings; use base 'DBIx::Class::Schema'; __PACKAGE__->load_namespaces; 1; 29.06.12 - Page 1
- 12. DBIC 'Dist' table class Département Office use utf8; package FPW12::DBIC::Result::Dist; use strict; use warnings; use base 'DBIx::Class::Core'; __PACKAGE__->table("dists"); __PACKAGE__->add_columns( dist_id => { data_type => "integer", is_nullable => 0, is_auto_increment => 1 }, dist_vers => { data_type => "varchar", is_nullable => 1, size => 20 }, ... # other columns ); __PACKAGE__->set_primary_key("dist_id"); __PACKAGE__->belongs_to ('auth', 'FPW12::DBIC::Result::Auth', 'auth_id'); __PACKAGE__->has_many ('mods', 'FPW12::DBIC::Result::Mod', 'dist_id'); __PACKAGE__->has_many ('depends', 'FPW12::DBIC::Result::Depends', 'dist_id'); __PACKAGE__->many_to_many(prereq_mods => 'depends', 'mod'); # idem for classes Auth, Mod, etc. 29.06.12 - Page 1
- 13. DBIDM centralized declarations use DBIx::DataModel; DBIx::DataModel->Schema("FPW12::DBIDM") # class table primary key # ===== ===== =========== ->Table(qw/Auth auths auth_id /) ->Table(qw/Dist dists dist_id /) ->Table(qw/Mod mods mod_id /) ->Table(qw/Depends depends dist_id mod_id/) # class role multipl. (optional join keys) # ===== ==== ======= ==================== ->Association([qw/Auth auth 1 auth_id /], [qw/Dist dists * auth_id /]) ->Composition([qw/Dist dist 1 /], [qw/Mod mods * /]) ->Association([qw/Dist dist 1 /], [qw/Depends depends * /]) ->Association([qw/Mod mod 1 /], [qw/Depends depends * /]) ->Association([qw/Dist used_in_dist * depends distrib /], [qw/Mod prereq_mods * depends mod /]) ;
- 14. Schema def. comparison Département Office • DBIC • DBIDM – one file for each class – centralized file – regular Perl classes – dynamic class creation – full column info – no column info (except pkey) – 1-way "relationships" – 2-ways "associations" with • belongs_to • multiplicities • has_many • role names • may_have • diff association/composition • …. – custom join conditions – custom column names • any operator • only equalities • 'foreign' and 'self' 29.06.12 - Page 1
- 15. Département Office Data retrieval 29.06.12 - Page 1
- 16. DBIC: Search Département Office use FPW12::DBIC; my $schema = FPW12::DBIC->connect($data_source); my @dists = $schema->resultset('Dist')->search( {dist_name => {-like => 'DBIx%'}}, {columns => [qw/dist_name dist_vers/]}, ); foreach my $dist (@dists) { printf "%s (%s)n", $dist->dist_name, $dist->dist_vers; } 29.06.12 - Page 1
- 17. DBIDM: Search Département Office use FPW12::DBIDM; use DBI; my $datasource = "dbi:SQLite:dbname=../cpandb.sql"; my $dbh = DBI->connect($datasource, "", "", {RaiseError => 1, AutoCommit => 1}); FPW12::DBIDM->dbh($dbh); my $dists = FPW12::DBIDM::Dist->select( -columns => [qw/dist_name dist_vers/], -where => {dist_name => {-like => 'DBIx%'}}, ); foreach my $dist (@$dists) { print "$dist->{dist_name} ($dist->{dist_vers})n"; } 29.06.12 - Page 1
- 18. Simple search comparison Département Office • DBIC • DBIDM – schema is an object – schema is a class (default) or an object – result is a list or a resultset object – result is an arrayref (default) – accessor methods for columns – hash entries for columns – uses SQL::Abstract – uses SQL::Abstract::More • mostly hidden • user can supply a custom $sqla obj 29.06.12 - Page 1
- 19. SQL::Abstract new() Département Office • special operators – ex: DBMS-independent fulltext search # where {field => {-contains => [qw/foo bar/]} my $sqla = SQL::Abstract->new(special_ops => [ {regex => qr/^contains(:?_all|_any)?$/i, handler => sub { my ($self, $field, $op, $arg) = @_; my $connector = ($op =~ /any$/) ? ' | ' : ' & '; my @vals = ref $arg ? @$arg : ($arg); @vals = map { split /s+/ } grep {$_} @vals; my $sql = sprintf "CONTAINS($field, '%s') > 0", join $connector, @vals; return ($sql); # no @bind } ]); 29.06.12 - Page 1
- 20. DBIC: Find single record Département Office my $auth1 = $schema->resultset('Auth') ->find(123); my $auth2 = $schema->resultset('Auth') ->find({cpanid => 'DAMI'}); 29.06.12 - Page 1
- 21. DBIDM: Find single record Département Office my $auth1 = FPW12::DBIDM::Auth->fetch(123); my $auth2 = FPW12::DBIDM::Auth->search( -where => {cpanid => 'DAMI'}, -result_as => 'firstrow', ); 29.06.12 - Page 1
- 22. DBIC: Search args Département Office • 1st arg : "where" criteria • 2nd arg : attributes – distinct – order_by – group_by, having – columns # list of columns to retrieve from main table – +columns # additional columns from joined tables or from functions – join # see later – prefetch # see later – for – page, rows, offset, etc. – cache 29.06.12 - Page 1
- 23. DBIDM: Select args my $result = $source->select( -columns => @columns,, -where => %where, -group_by => @groupings, -having => %criteria, -order_by => @order, -for => 'read only', -post_SQL => sub { … }, -pre_exec => sub { … }, -post_exec => sub { … }, -post_bless => sub { … }, -page_size => …, -page_index => …, -limit => …, -offset => …, -column_types => %types, -result_as => $result_type, );
- 24. DBIDM: Polymorphic result -result_as => – 'rows' (default) : arrayref of row objects – 'firstrow' : a single row object (or undef) – 'hashref' : hashref keyed by primary keys – [hashref => @cols] : cascaded hashref – 'flat_arrayref' : flattened values from each row – 'statement' : a statement object (iterator) – 'fast_statement' : statement reusing same memory – 'sth' : DBI statement handle – 'sql' : ($sql, @bind_values) – 'subquery' : ["($sql)", @bind] don't need method variants : select_hashref(), select_arrayref(), etc.
- 25. DBIDM: Fast statement • like a regular statement – but reuses the same memory location for each row – see DBI::bind_col() my $statement = $source->select( . . . , -result_as => 'fast_statement' ); while (my $row = $statement->next) { . . . # DO THIS : print $row->{col1}, $row->{col2} # BUT DON'T DO THIS : push @results, $row; }
- 26. Advanced search comparison • DBIC • DBIDM – 'find' by any unique constraint – 'fetch' by primary key only – "inner" vs "outer" columns – all columns equal citizens – result is context-dependent – polymorphic result – optional caching – no caching – statement-specific inflators – callbacks
- 27. Joins
- 28. Task : list distributions and their authors Author 1 * 1 contains ► 1..* Distribution Module * * depends_on ►
- 29. DBIC: Join my @dists = $schema->resultset('Dist')->search( {dist_name => {-like => 'DBIx%'}}, {columns => [qw/dist_name dist_vers/], join => 'auth', '+columns' => [{'fullname' => 'auth.fullname'}], }, ); foreach my $dist (@dists) { printf "%s (%s) by %sn", $dist->dist_name, $dist->dist_vers, $dist->get_column('fullname'); # no accessor meth }
- 30. DBIC: Join with prefetch my @dists = $schema->resultset('Dist')->search( {dist_name => {-like => 'DBIx%'}}, {columns => [qw/dist_name dist_vers/], prefetch => 'auth', }, ); foreach my $dist (@dists) { printf "%s (%s) by %sn", $dist->dist_name, $dist->dist_vers, $dist->auth->fullname; # already in memory }
- 31. DBIDM: Join my $rows = FPW12::DBIDM->join(qw/Dist auth/)->select( -columns => [qw/dist_name dist_vers fullname/], -where => {dist_name => {-like => 'DBIx%'}}, ); foreach my $row (@$rows) { print "$row->{dist_name} ($row->{dist_vers}) " . "by $row->{fullname}n"; } Dist Auth DBIDM::Source::Join new class created on the fly ..::AutoJoin::…
- 32. Multiple joins • DBIC join => [ { abc => { def => 'ghi' } }, { jkl => 'mno' }, 'pqr' ] • DBIDM ->join(qw/Root abc def ghi jkl mno pqr/)
- 33. Join from an existing record • DBIC my $rs = $auth->dists(undef, {join|prefetch => 'mods'}); • DBIDM my $rows = $auth->join(qw/dists mods/)->select;
- 34. DBIC: left/inner joins • attribute when declaring relationships # in a Book class (where Author has_many Books) __PACKAGE__->belongs_to( author => 'My::DBIC::Schema::Author', 'author', { join_type => 'left' } ); • cannot change later (when invoking the relationship)
- 35. DBIDM: Left / inner joins ->Association([qw/Author author 1 /], [qw/Distribution distribs 0..* /]) # default : LEFT OUTER JOIN ->Composition([qw/Distribution distrib 1 /], [qw/Module modules 1..* /]); # default : INNER JOIN # but defaults can be overridden My::DB->join([qw/Author <=> distribs/)-> . . . My::DB->join([qw/Distribution => modules /)-> . . .
- 36. Join comparison • DBIC • DBIDM – rows belong to 1 table class only – rows inherit from all joined tables – joined columns are either – flattening of all columns • "side-products", • prefetched (all of them, no choice) – fixed join type – default join type, can be overridden
- 37. Speed
- 38. Select speed Département Office list mods join Auth dist mods (109349 rows) (113895 rows) DBI 0.43 secs 1.36 secs DBIC regular 11.09 secs 15.50 secs DBIC prefetch n.a. 146.29 secs DBIC hashref inflator 10.06 secs 14.17 secs DBIDM regular 4.00 secs 5.01 secs DBIDM 2.25 secs 3.28 secs fast_statement 29.06.12 - Page 1
- 39. Insert speed Département Office insert (72993 rows) DBI 5.8 secs DBIC regular 40.35 secs DBIC populate 5.6 secs DBIDM regular 32.81 secs DBIDM bulk 32.57 secs 29.06.12 - Page 1
- 40. Département Office Classes and methods 29.06.12 - Page 1
- 41. DBIC : methods of a row DB<1> m $auth # 152 methods DB<4> x mro::get_linear_isa(ref $auth) _auth_id_accessor 0 ARRAY(0x13826c4) _cpanid_accessor 0 'FPW12::DBIC::Result::Auth' _email_accessor 1 'DBIx::Class::Core' _fullname_accessor 2 'DBIx::Class::Relationship' _result_source_instance_accessor 3 'DBIx::Class::Relationship::Helpers' add_to_dists 4 'DBIx::Class::Relationship::HasMany' auth_id 5 'DBIx::Class::Relationship::HasOne' cpanid 6 'DBIx::Class::Relationship::BelongsTo' dists 7 'DBIx::Class::Relationship::ManyToMany' dists_rs 8 'DBIx::Class' email 9 'DBIx::Class::Componentised' fullname 10 'Class::C3::Componentised' result_source_instance 11 'DBIx::Class::AccessorGroup' via DBIx::Class::Core -> DBIx::Class::Relationship 12 'Class::Accessor::Grouped' -> DBIx::Class::Relationship::Helpers -> 13 'DBIx::Class::Relationship::Accessor' DBIx::Class::Relationship::HasMany: has_many 14 'DBIx::Class::Relationship::CascadeActions' via DBIx::Class::Core -> DBIx::Class::Relationship -> DBIx::Class::Relationship::Helpers -> 15 'DBIx::Class::Relationship::ProxyMethods' DBIx::Class::Relationship::HasOne: 16 'DBIx::Class::Relationship::Base' _get_primary_key 17 'DBIx::Class::InflateColumn' via DBIx::Class::Core -> DBIx::Class::Relationship 18 'DBIx::Class::Row' -> DBIx::Class::Relationship::Helpers -> 19 'DBIx::Class::PK::Auto' DBIx::Class::Relationship::HasOne: _has_one 20 'DBIx::Class::PK' via DBIx::Class::Core -> DBIx::Class::Relationship -> DBIx::Class::Relationship::Helpers -> 21 'DBIx::Class::ResultSourceProxy::Table' DBIx::Class::Relationship::HasOne: 22 'DBIx::Class::ResultSourceProxy' _validate_has_one_condition via DBIx::Class::Core -> DBIx::Class::Relationship -> DBIx::Class::Relationship::Helpers -> DBIx::Class::Relationship::HasOne: has_one ...
- 42. DBIDM : methods of a row DB<1> m $auth # 36 methods DB<4> x mro::get_linear_isa(ref $auth) dists insert_into_dists 0 ARRAY(0x145275c) metadm 0 'FPW12::DBIDM::Auth' via DBIx::DataModel::Source::Table: _get_last_insert_id 1 'DBIx::DataModel::Source::Table' via DBIx::DataModel::Source::Table: 2 'DBIx::DataModel::Source' _insert_subtrees via DBIx::DataModel::Source::Table: _rawInsert via DBIx::DataModel::Source::Table: _singleInsert via DBIx::DataModel::Source::Table: _weed_out_subtrees via DBIx::DataModel::Source::Table: delete via DBIx::DataModel::Source::Table: has_invalid_columns via DBIx::DataModel::Source::Table: insert via DBIx::DataModel::Source::Table: update via DBIx::DataModel::Source::Table -> DBIx::DataModel::Source: TO_JSON via DBIx::DataModel::Source::Table -> DBIx::DataModel::Source: apply_column_handler via DBIx::DataModel::Source::Table -> DBIx::DataModel::Source: auto_expand via DBIx::DataModel::Source::Table -> DBIx::DataModel::Source: bless_from_DB via DBIx::DataModel::Source::Table -> DBIx::DataModel::Source: expand via DBIx::DataModel::Source::Table -> DBIx::DataModel::Source: fetch
- 43. DBIC classes Componentised AccessorGroup BelongsTo, HasMany, etc. BelongsTo, HasMany, etc. Class RLHelpers RLBase Row RSProxy ResultSource RS::Table Relationship InflateColumn PK::Auto PK RSProxy::Table Schema Core ResultSet application classes My::DB My::DB::Result::Table_n My::DB::ResultSet::Table_n objects schema row resultset instantiation inheritance delegation
- 44. DBIDM classes Source Schema Table Join Statement application classes My::DB My::DB::Table_n My::DB::AutoJoin:: objects schema row row statement
- 45. DBIDM Meta-Architecture Meta::Schema Meta::Association Meta::Path Meta::Source Meta::Type meta::assoc meta::path Meta::Table Meta::Join meta::type Schema Table Join My::DB meta::schema My::DB::Table_n meta::table My::DB::Auto_join meta::join
- 46. DBIC introspection methods • Schema – sources(), source($source_name) • ResultSource – primary_key – columns(), column_info($column_name) – relationships(), relationship_info($relname)
- 47. Architecture comparison • DBIC • DBIDM – very complex class structure – classes quite close to DBI concepts – no distinction front/meta layser – front classes and Meta classes – methods for – methods for • CRUD • CRUD • navigation to related objs • navigation to related objs • introspection • access to meta • setting up columns • setting up relationships • …
- 48. Département Office Resultset/Statement objects 29.06.12 - Page 1
- 49. Example task Département Office • list names of authors – of distribs starting with 'DBIx' – and version number > 2 29.06.12 - Page 1
- 50. DBIC ResultSet chaining Département Office my $dists = $schema->resultset('Dist')->search( {dist_name => {-like => 'DBIx%'}}, ); my $big_vers = $dists->search({dist_vers => { ">" => 2}}); my @auths = $big_vers->search_related('auth', undef, {distinct => 1, order_by => 'fullname'}); say $_->fullname foreach @auths; # Magical join ! Magical "group by" ! SELECT auth.auth_id, auth.email, auth.fullname, auth.cpanid FROM dists me JOIN auths auth ON auth.auth_id = me.auth_id WHERE ( ( dist_vers > ? AND dist_name LIKE ? ) ) GROUP BY auth.auth_id, auth.email, auth.fullname, auth.cpanid ORDER BY fullname 29.06.12 - Page 1
- 51. DBIDM Statement lifecycle new() schema + source new refine() sqlize() bind() -post_SQL sqlized prepare() bind() -pre_exec prepared execute() bind() -post_exec executed execute() -post_bless next() / all() bind() column types applied blessed data row(s)
- 52. DBIDM Statement::refine() my $stmt = FPW12::DBIDM->join(qw/Dist auth/)->select( -where => {dist_name => {-like => 'DBIx%'}}, -result_as => 'statement', ); $stmt->refine( -columns => [-DISTINCT => 'fullname'], -where => {dist_vers => { ">" => 0}}, -order_by => 'fullname', ); say $_->{fullname} while $_ = $stmt->next;
- 53. DBIDM subquery my $stmt = FPW12::DBIDM::Dist->select( -where => {dist_name => {-like => 'DBIx%'}}, -result_as => 'statement', ); my $subquery = $stmt->select( -columns => 'auth_id', -where => {dist_vers => { ">" => 2}}, -result_as => 'subquery', ); my $auths = FPW12::DBIDM::Auth->select( -columns => 'fullname', -where => {auth_id => {-in => $subquery}}, ); say $_->{fullname} foreach @$rows;
- 54. Statement comparison • DBIC • DBIDM – powerful refinement constructs – limited refinement constructs • more "where" criteria – explicit control of status • navigation to related source • column restriction • aggregation operators (e.g. "count")
- 55. Département Office Other features 29.06.12 - Page 1
- 56. Transactions Département Office • DBIC • DBIDM $schema->txn_do($sub); $sch->do_transaction($sub); – can be nested – can be nested – can have intermediate savepoints – no intermediate savepoints 29.06.12 - Page 1
- 57. DBIC inflation/deflation __PACKAGE__->inflate_column('insert_time', {inflate => sub { DateTime::Format::Pg->parse_datetime(shift); }, deflate => sub { DateTime::Format::Pg->format_datetime(shift) }, });
- 58. DBIDM Types (inflate/deflate) # declare a Type My::DB->Type(Multivalue => from_DB => sub {$_[0] = [split /;/, $_[0]] }, to_DB => sub {$_[0] = join ";", @$_[0] }, ); # apply it to some columns in a table My::DB::Author->metadm->define_column_type( Multivalue => qw/hobbies languages/, );
- 59. Extending/customizing DBIC • Subclassing – result classes – resultset classes – storage – sqlmaker
- 60. Extending / customizing DBIDM • Schema hooks for – SQL dialects (join syntax, alias syntax, limit / offset, etc.) – last_insert_id • Ad hoc subclasses for – SQL::Abstract – Table – Join – Statements • Statement callbacks • Extending table classes – additional methods – redefining _singleInsert method
- 61. Not covered here • inserts, updates, deletes • Schema generator • Schema versioning • inflation/deflation
- 62. Département Office THANK YOU FOR YOUR ATTENTION 29.06.12 - Page 1
- 63. Département Office Bonus slides 29.06.12 - Page 1
- 64. Why hashref instead of OO accessors ? • Perl builtin rich API for hashes (keys, values, slices, string interpolation) • good for import / export in YAML/XML/JSON • easier to follow steps in Perl debugger • faster than OO accessor methods • visually clear distinction between lvalue / rvalue – my $val = $hashref->{column}; – $hashref->{column} = $val; • visually clear distinction between – $row->{column} / $row->remote_table()
- 65. SQL::Abstract::More : extensions • -columns => [qw/col1|alias1 max(col2)|alias2/] – SELECT col1 AS alias1, max(col2) AS alias2 • -columns => [-DISTINCT => qw/col1 col2 col3/] – SELECT DISTINCT col1, col2, col3 • -order_by => [qw/col1 +col2 –col3/] – SELECT … ORDER BY col1, col2 ASC, col3 DESC • -for => "update" || "read only" – SELECT … FOR UPDATE