Factor SQL-standard deferred FK checks into a component

[dbsrgits/DBIx-Class.git] / lib / DBIx / Class / Storage / DBI / SetConstraintsDeferred.pm

diff --git a/lib/DBIx/Class/Storage/DBI/SetConstraintsDeferred.pm b/lib/DBIx/Class/Storage/DBI/SetConstraintsDeferred.pm
new file mode 100644 (file)
index 0000000..6784c7c
--- /dev/null
+++ b/lib/DBIx/Class/Storage/DBI/SetConstraintsDeferred.pm
@@ -0,0 +1,55 @@
+package DBIx::Class::Storage::DBI::SetConstraintsDeferred;
+
+use strict;
+use warnings;
+
+use base 'DBIx::Class::Storage::DBI';
+use mro 'c3';
+
+use Scope::Guard ();
+use Context::Preserve 'preserve_context';
+
+use namespace::clean;
+
+=head1 NAME
+
+DBIx::Class::Storage::DBI::SetConstraintsDeferred - Storage component for deferred constraints via C<SET CONSTRAINTS>
+
+=head1 DESCRIPTION
+
+This component implements L<DBIx::Class::Storage::DBI/with_deferred_fk_checks>
+by wrapping the the coderef in C<SET CONSTRAINTS ALL DEFERRED> and
+C<SET CONSTRAINTS ALL IMMEDIATE>.
+
+=cut
+
+sub with_deferred_fk_checks {
+  my ($self, $sub) = @_;
+
+  my $txn_scope_guard = $self->txn_scope_guard;
+
+  $self->_do_query('SET CONSTRAINTS ALL DEFERRED');
+
+  return preserve_context {
+    my $inner_self = $self; # avoid nested closure leak on 5.8
+    my $sg = Scope::Guard->new(sub {
+      $inner_self->_do_query('SET CONSTRAINTS ALL IMMEDIATE');
+    });
+    $sub->()
+  } after => sub { $txn_scope_guard->commit };
+}
+
+=head1 FURTHER QUESTIONS?
+
+Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>.
+
+=head1 COPYRIGHT AND LICENSE
+
+This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE>
+by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can
+redistribute it and/or modify it under the same terms as the
+L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>.
+
+=cut
+
+1;