From: Matt S Trout Date: Mon, 7 Oct 2019 01:42:20 +0000 (+0000) Subject: document bangoverrides, add example X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=b10168404805faba08bbc67249e7f297102a1cc0;p=scpubgit%2FQ-Branch.git document bangoverrides, add example --- diff --git a/examples/dbicbits b/examples/dbicbits new file mode 100644 index 0000000..7e4a6f0 --- /dev/null +++ b/examples/dbicbits @@ -0,0 +1,58 @@ +use strict; +use warnings; +{ + package MySchema; + use Object::Tap; + use base qw(DBIx::Class::Schema); + use DBIx::Class::ResultSource::Table; + __PACKAGE__->register_source( + Foo => DBIx::Class::ResultSource::Table->new({ name => 'foo' }) + ->$_tap(add_columns => qw(x y z)) + ); + __PACKAGE__->register_source( + Bar => DBIx::Class::ResultSource::Table->new({ name => 'bar' }) + ->$_tap(add_columns => qw(a b c)) + ); +} + +my $s = MySchema->connect('dbi:SQLite:dbname=:memory:'); + +my $rs = $s->resultset('Foo')->search({ z => 1 }); + +warn ${$rs->as_query}->[0]."\n"; + +$s->storage->ensure_connected; + +$s->storage + ->sql_maker->plugin('+ExtraClauses')->plugin('+BangOverrides'); + +my $rs2 = $s->resultset('Foo')->search({ + -op => [ '=', { -ident => 'outer.y' }, { -ident => 'me.x' } ] +}, { + with_recursive => [ outer => $rs->get_column('x')->as_query ], +}); + +warn ${$rs2->as_query}->[0]."\n"; + +my $rs3 = $rs2->search({}, { + '!from' => sub { my ($sqla, $from) = @_; + my $base = $sqla->expand_expr({ -old_from => $from }); + return [ $base, -join => [ 'wub', on => [ 'me.z' => 'wub.z' ] ] ]; + } +}); + +warn ${$rs3->as_query}->[0]."\n"; + +my $rs4 = $rs3->search({}, { + '!with' => [ [ qw(wub x y z) ], $s->resultset('Bar')->as_query ], +}); + +warn ${$rs4->as_query}->[0]."\n"; + +my $rs5 = $rs->search({}, { select => [ { -coalesce => [ { -ident => 'x' }, { -value => 7 } ] } ] }); + +warn ${$rs5->as_query}->[0]."\n"; + +my $rs6 = $rs->search({}, { '!select' => [ { -coalesce => [ { -ident => 'x' }, { -value => 7 } ] } ] }); + +warn ${$rs6->as_query}->[0]."\n"; diff --git a/lib/SQL/Abstract/Plugin/BangOverrides.pm b/lib/SQL/Abstract/Plugin/BangOverrides.pm index dae9d0c..9ef6a61 100644 --- a/lib/SQL/Abstract/Plugin/BangOverrides.pm +++ b/lib/SQL/Abstract/Plugin/BangOverrides.pm @@ -33,3 +33,56 @@ sub register_extensions { } 1; + +__END__ + +=head1 NAME + +SQL::Abstract::Plugin::BangOverrides + +=head2 SYNOPSIS + + $sqla->plugin('+BangOverrides'); + ... + profit(); + +=head1 METHODS + +=head2 register_extensions + +Wraps all currently existing clause based statements such that when a clause +of '!name' is encountered, if its value is a coderef, it's called with the +original value of the 'name' clause and expected to return a replacement, and +if not, it's simply used as a direct replacement. + +So, given appropriate DBIC setup: + + $s->storage->sqlmaker->plugin('+ExtraClauses')->plugin('+BangOverrides'); + + my $rs2 = $s->resultset('Foo')->search({ + -op => [ '=', { -ident => 'outer.y' }, { -ident => 'me.x' } ] + }, { + with_recursive => [ outer => $rs->get_column('x')->as_query ], + }); + # (SELECT me.x, me.y, me.z FROM foo me WHERE ( outer.y = me.x )) + + my $rs3 = $rs2->search({}, { + '!from' => sub { my ($sqla, $from) = @_; + my $base = $sqla->expand_expr({ -old_from => $from }); + return [ $base, -join => [ 'wub', on => [ 'me.z' => 'wub.z' ] ] ]; + } + }); + # (SELECT me.x, me.y, me.z FROM foo me JOIN wub ON me.z = wub.z WHERE ( outer.y = me.x )) + + my $rs4 = $rs3->search({}, { + '!with' => [ [ qw(wub x y z) ], $s->resultset('Bar')->as_query ], + }); + # (WITH wub(x, y, z) AS (SELECT me.a, me.b, me.c FROM bar me) SELECT me.x, me.y, me.z FROM foo me JOIN wub ON me.z = wub.z WHERE ( outer.y = me.x )) + + my $rs5 = $rs->search({}, { select => [ { -coalesce => [ { -ident => 'x' }, { -value => 7 } ] } ] }); + # (SELECT -COALESCE( -IDENT( x ), -VALUE( 7 ) ) FROM foo me WHERE ( z = ? )) + + my $rs6 = $rs->search({}, { '!select' => [ { -coalesce => [ { -ident => 'x' }, { -value => 7 } ] } ] }); + # (SELECT COALESCE(x, ?) FROM foo me WHERE ( z = ? )) + +=cut