1 package DBIx::Class::Storage::DBI;
2 # -*- mode: cperl; cperl-indent-level: 2 -*-
4 use base 'DBIx::Class::Storage';
8 use Carp::Clan qw/^DBIx::Class/;
10 use SQL::Abstract::Limit;
11 use DBIx::Class::Storage::DBI::Cursor;
12 use DBIx::Class::Storage::Statistics;
13 use Scalar::Util qw/blessed weaken/;
15 __PACKAGE__->mk_group_accessors('simple' =>
16 qw/_connect_info _dbi_connect_info _dbh _sql_maker _sql_maker_opts
17 _conn_pid _conn_tid transaction_depth _dbh_autocommit savepoints/
20 # the values for these accessors are picked out (and deleted) from
21 # the attribute hashref passed to connect_info
22 my @storage_options = qw/
23 on_connect_do on_disconnect_do disable_sth_caching unsafe auto_savepoint
25 __PACKAGE__->mk_group_accessors('simple' => @storage_options);
28 # default cursor class, overridable in connect_info attributes
29 __PACKAGE__->cursor_class('DBIx::Class::Storage::DBI::Cursor');
31 __PACKAGE__->mk_group_accessors('inherited' => qw/sql_maker_class/);
32 __PACKAGE__->sql_maker_class('DBIC::SQL::Abstract');
36 package # Hide from PAUSE
37 DBIC::SQL::Abstract; # Would merge upstream, but nate doesn't reply :(
39 use base qw/SQL::Abstract::Limit/;
41 # This prevents the caching of $dbh in S::A::L, I believe
43 my $self = shift->SUPER::new(@_);
45 # If limit_dialect is a ref (like a $dbh), go ahead and replace
46 # it with what it resolves to:
47 $self->{limit_dialect} = $self->_find_syntax($self->{limit_dialect})
48 if ref $self->{limit_dialect};
53 # DB2 is the only remaining DB using this. Even though we are not sure if
54 # RowNumberOver is still needed here (should be part of SQLA) leave the
57 my ($self, $sql, $order, $rows, $offset ) = @_;
60 my $last = $rows + $offset;
61 my ( $order_by ) = $self->_order_by( $order );
66 SELECT Q1.*, ROW_NUMBER() OVER( ) AS ROW_NUM FROM (
71 WHERE ROW_NUM BETWEEN $offset AND $last
79 # While we're at it, this should make LIMIT queries more efficient,
80 # without digging into things too deeply
81 use Scalar::Util 'blessed';
83 my ($self, $syntax) = @_;
85 # DB2 is the only remaining DB using this. Even though we are not sure if
86 # RowNumberOver is still needed here (should be part of SQLA) leave the
88 my $dbhname = blessed($syntax) ? $syntax->{Driver}{Name} : $syntax;
89 if(ref($self) && $dbhname && $dbhname eq 'DB2') {
90 return 'RowNumberOver';
93 $self->{_cached_syntax} ||= $self->SUPER::_find_syntax($syntax);
97 my ($self, $table, $fields, $where, $order, @rest) = @_;
98 if (ref $table eq 'SCALAR') {
101 elsif (not ref $table) {
102 $table = $self->_quote($table);
104 local $self->{rownum_hack_count} = 1
105 if (defined $rest[0] && $self->{limit_dialect} eq 'RowNum');
106 @rest = (-1) unless defined $rest[0];
107 die "LIMIT 0 Does Not Compute" if $rest[0] == 0;
108 # and anyway, SQL::Abstract::Limit will cause a barf if we don't first
109 local $self->{having_bind} = [];
110 my ($sql, @ret) = $self->SUPER::select(
111 $table, $self->_recurse_fields($fields), $where, $order, @rest
116 $self->{for} eq 'update' ? ' FOR UPDATE' :
117 $self->{for} eq 'shared' ? ' FOR SHARE' :
122 return wantarray ? ($sql, @ret, @{$self->{having_bind}}) : $sql;
128 $table = $self->_quote($table) unless ref($table);
129 $self->SUPER::insert($table, @_);
135 $table = $self->_quote($table) unless ref($table);
136 $self->SUPER::update($table, @_);
142 $table = $self->_quote($table) unless ref($table);
143 $self->SUPER::delete($table, @_);
149 return $_[1].$self->_order_by($_[2]);
151 return $self->SUPER::_emulate_limit(@_);
155 sub _recurse_fields {
156 my ($self, $fields, $params) = @_;
157 my $ref = ref $fields;
158 return $self->_quote($fields) unless $ref;
159 return $$fields if $ref eq 'SCALAR';
161 if ($ref eq 'ARRAY') {
162 return join(', ', map {
163 $self->_recurse_fields($_)
164 .(exists $self->{rownum_hack_count} && !($params && $params->{no_rownum_hack})
165 ? ' AS col'.$self->{rownum_hack_count}++
168 } elsif ($ref eq 'HASH') {
169 foreach my $func (keys %$fields) {
170 return $self->_sqlcase($func)
171 .'( '.$self->_recurse_fields($fields->{$func}).' )';
180 if (ref $_[0] eq 'HASH') {
181 if (defined $_[0]->{group_by}) {
182 $ret = $self->_sqlcase(' group by ')
183 .$self->_recurse_fields($_[0]->{group_by}, { no_rownum_hack => 1 });
185 if (defined $_[0]->{having}) {
187 ($frag, @extra) = $self->_recurse_where($_[0]->{having});
188 push(@{$self->{having_bind}}, @extra);
189 $ret .= $self->_sqlcase(' having ').$frag;
191 if (defined $_[0]->{order_by}) {
192 $ret .= $self->_order_by($_[0]->{order_by});
194 if (grep { $_ =~ /^-(desc|asc)/i } keys %{$_[0]}) {
195 return $self->SUPER::_order_by($_[0]);
197 } elsif (ref $_[0] eq 'SCALAR') {
198 $ret = $self->_sqlcase(' order by ').${ $_[0] };
199 } elsif (ref $_[0] eq 'ARRAY' && @{$_[0]}) {
200 my @order = @{+shift};
201 $ret = $self->_sqlcase(' order by ')
203 my $r = $self->_order_by($_, @_);
204 $r =~ s/^ ?ORDER BY //i;
208 $ret = $self->SUPER::_order_by(@_);
213 sub _order_directions {
214 my ($self, $order) = @_;
215 $order = $order->{order_by} if ref $order eq 'HASH';
216 return $self->SUPER::_order_directions($order);
220 my ($self, $from) = @_;
221 if (ref $from eq 'ARRAY') {
222 return $self->_recurse_from(@$from);
223 } elsif (ref $from eq 'HASH') {
224 return $self->_make_as($from);
226 return $from; # would love to quote here but _table ends up getting called
227 # twice during an ->select without a limit clause due to
228 # the way S::A::Limit->select works. should maybe consider
229 # bypassing this and doing S::A::select($self, ...) in
230 # our select method above. meantime, quoting shims have
231 # been added to select/insert/update/delete here
236 my ($self, $from, @join) = @_;
238 push(@sqlf, $self->_make_as($from));
239 foreach my $j (@join) {
242 # check whether a join type exists
243 my $join_clause = '';
244 my $to_jt = ref($to) eq 'ARRAY' ? $to->[0] : $to;
245 if (ref($to_jt) eq 'HASH' and exists($to_jt->{-join_type})) {
246 $join_clause = ' '.uc($to_jt->{-join_type}).' JOIN ';
248 $join_clause = ' JOIN ';
250 push(@sqlf, $join_clause);
252 if (ref $to eq 'ARRAY') {
253 push(@sqlf, '(', $self->_recurse_from(@$to), ')');
255 push(@sqlf, $self->_make_as($to));
257 push(@sqlf, ' ON ', $self->_join_condition($on));
259 return join('', @sqlf);
263 my ($self, $from) = @_;
264 return join(' ', map { (ref $_ eq 'SCALAR' ? $$_ : $self->_quote($_)) }
265 reverse each %{$self->_skip_options($from)});
269 my ($self, $hash) = @_;
271 $clean_hash->{$_} = $hash->{$_}
272 for grep {!/^-/} keys %$hash;
276 sub _join_condition {
277 my ($self, $cond) = @_;
278 if (ref $cond eq 'HASH') {
283 # XXX no throw_exception() in this package and croak() fails with strange results
284 Carp::croak(ref($v) . qq{ reference arguments are not supported in JOINS - try using \"..." instead'})
285 if ref($v) ne 'SCALAR';
289 my $x = '= '.$self->_quote($v); $j{$_} = \$x;
292 return scalar($self->_recurse_where(\%j));
293 } elsif (ref $cond eq 'ARRAY') {
294 return join(' OR ', map { $self->_join_condition($_) } @$cond);
296 die "Can't handle this yet!";
301 my ($self, $label) = @_;
302 return '' unless defined $label;
303 return "*" if $label eq '*';
304 return $label unless $self->{quote_char};
305 if(ref $self->{quote_char} eq "ARRAY"){
306 return $self->{quote_char}->[0] . $label . $self->{quote_char}->[1]
307 if !defined $self->{name_sep};
308 my $sep = $self->{name_sep};
309 return join($self->{name_sep},
310 map { $self->{quote_char}->[0] . $_ . $self->{quote_char}->[1] }
311 split(/\Q$sep\E/,$label));
313 return $self->SUPER::_quote($label);
318 $self->{limit_dialect} = shift if @_;
319 return $self->{limit_dialect};
324 $self->{quote_char} = shift if @_;
325 return $self->{quote_char};
330 $self->{name_sep} = shift if @_;
331 return $self->{name_sep};
334 } # End of BEGIN block
338 DBIx::Class::Storage::DBI - DBI storage handler
342 my $schema = MySchema->connect('dbi:SQLite:my.db');
344 $schema->storage->debug(1);
345 $schema->dbh_do("DROP TABLE authors");
347 $schema->resultset('Book')->search({
348 written_on => $schema->storage->datetime_parser(DateTime->now)
353 This class represents the connection to an RDBMS via L<DBI>. See
354 L<DBIx::Class::Storage> for general information. This pod only
355 documents DBI-specific methods and behaviors.
362 my $new = shift->next::method(@_);
364 $new->transaction_depth(0);
365 $new->_sql_maker_opts({});
366 $new->{savepoints} = [];
367 $new->{_in_dbh_do} = 0;
368 $new->{_dbh_gen} = 0;
375 This method is normally called by L<DBIx::Class::Schema/connection>, which
376 encapsulates its argument list in an arrayref before passing them here.
378 The argument list may contain:
384 The same 4-element argument set one would normally pass to
385 L<DBI/connect>, optionally followed by
386 L<extra attributes|/DBIx::Class specific connection attributes>
387 recognized by DBIx::Class:
389 $connect_info_args = [ $dsn, $user, $password, \%dbi_attributes?, \%extra_attributes? ];
393 A single code reference which returns a connected
394 L<DBI database handle|DBI/connect> optionally followed by
395 L<extra attributes|/DBIx::Class specific connection attributes> recognized
398 $connect_info_args = [ sub { DBI->connect (...) }, \%extra_attributes? ];
402 A single hashref with all the attributes and the dsn/user/password
405 $connect_info_args = [{
413 This is particularly useful for L<Catalyst> based applications, allowing the
414 following config (L<Config::General> style):
419 dsn dbi:mysql:database=test
428 Please note that the L<DBI> docs recommend that you always explicitly
429 set C<AutoCommit> to either I<0> or I<1>. L<DBIx::Class> further
430 recommends that it be set to I<1>, and that you perform transactions
431 via our L<DBIx::Class::Schema/txn_do> method. L<DBIx::Class> will set it
432 to I<1> if you do not do explicitly set it to zero. This is the default
433 for most DBDs. See L</DBIx::Class and AutoCommit> for details.
435 =head3 DBIx::Class specific connection attributes
437 In addition to the standard L<DBI|DBI/ATTRIBUTES_COMMON_TO_ALL_HANDLES>
438 L<connection|DBI/Database_Handle_Attributes> attributes, DBIx::Class recognizes
439 the following connection options. These options can be mixed in with your other
440 L<DBI> connection attributes, or placed in a seperate hashref
441 (C<\%extra_attributes>) as shown above.
443 Every time C<connect_info> is invoked, any previous settings for
444 these options will be cleared before setting the new ones, regardless of
445 whether any options are specified in the new C<connect_info>.
452 Specifies things to do immediately after connecting or re-connecting to
453 the database. Its value may contain:
457 =item an array reference
459 This contains SQL statements to execute in order. Each element contains
460 a string or a code reference that returns a string.
462 =item a code reference
464 This contains some code to execute. Unlike code references within an
465 array reference, its return value is ignored.
469 =item on_disconnect_do
471 Takes arguments in the same form as L</on_connect_do> and executes them
472 immediately before disconnecting from the database.
474 Note, this only runs if you explicitly call L</disconnect> on the
477 =item disable_sth_caching
479 If set to a true value, this option will disable the caching of
480 statement handles via L<DBI/prepare_cached>.
484 Sets the limit dialect. This is useful for JDBC-bridge among others
485 where the remote SQL-dialect cannot be determined by the name of the
486 driver alone. See also L<SQL::Abstract::Limit>.
490 Specifies what characters to use to quote table and column names. If
491 you use this you will want to specify L</name_sep> as well.
493 C<quote_char> expects either a single character, in which case is it
494 is placed on either side of the table/column name, or an arrayref of length
495 2 in which case the table/column name is placed between the elements.
497 For example under MySQL you should use C<< quote_char => '`' >>, and for
498 SQL Server you should use C<< quote_char => [qw/[ ]/] >>.
502 This only needs to be used in conjunction with C<quote_char>, and is used to
503 specify the charecter that seperates elements (schemas, tables, columns) from
504 each other. In most cases this is simply a C<.>.
506 The consequences of not supplying this value is that L<SQL::Abstract>
507 will assume DBIx::Class' uses of aliases to be complete column
508 names. The output will look like I<"me.name"> when it should actually
513 This Storage driver normally installs its own C<HandleError>, sets
514 C<RaiseError> and C<ShowErrorStatement> on, and sets C<PrintError> off on
515 all database handles, including those supplied by a coderef. It does this
516 so that it can have consistent and useful error behavior.
518 If you set this option to a true value, Storage will not do its usual
519 modifications to the database handle's attributes, and instead relies on
520 the settings in your connect_info DBI options (or the values you set in
521 your connection coderef, in the case that you are connecting via coderef).
523 Note that your custom settings can cause Storage to malfunction,
524 especially if you set a C<HandleError> handler that suppresses exceptions
525 and/or disable C<RaiseError>.
529 If this option is true, L<DBIx::Class> will use savepoints when nesting
530 transactions, making it possible to recover from failure in the inner
531 transaction without having to abort all outer transactions.
535 Use this argument to supply a cursor class other than the default
536 L<DBIx::Class::Storage::DBI::Cursor>.
540 Some real-life examples of arguments to L</connect_info> and
541 L<DBIx::Class::Schema/connect>
543 # Simple SQLite connection
544 ->connect_info([ 'dbi:SQLite:./foo.db' ]);
547 ->connect_info([ sub { DBI->connect(...) } ]);
549 # A bit more complicated
556 { quote_char => q{"}, name_sep => q{.} },
560 # Equivalent to the previous example
566 { AutoCommit => 1, quote_char => q{"}, name_sep => q{.} },
570 # Same, but with hashref as argument
571 # See parse_connect_info for explanation
574 dsn => 'dbi:Pg:dbname=foo',
576 password => 'my_pg_password',
583 # Subref + DBIx::Class-specific connection options
586 sub { DBI->connect(...) },
590 on_connect_do => ['SET search_path TO myschema,otherschema,public'],
591 disable_sth_caching => 1,
601 my ($self, $info_arg) = @_;
603 return $self->_connect_info if !$info_arg;
605 my @args = @$info_arg; # take a shallow copy for further mutilation
606 $self->_connect_info([@args]); # copy for _connect_info
609 # combine/pre-parse arguments depending on invocation style
612 if (ref $args[0] eq 'CODE') { # coderef with optional \%extra_attributes
613 %attrs = %{ $args[1] || {} };
616 elsif (ref $args[0] eq 'HASH') { # single hashref (i.e. Catalyst config)
617 %attrs = %{$args[0]};
619 for (qw/password user dsn/) {
620 unshift @args, delete $attrs{$_};
623 else { # otherwise assume dsn/user/password + \%attrs + \%extra_attrs
625 % { $args[3] || {} },
626 % { $args[4] || {} },
628 @args = @args[0,1,2];
631 # Kill sql_maker/_sql_maker_opts, so we get a fresh one with only
632 # the new set of options
633 $self->_sql_maker(undef);
634 $self->_sql_maker_opts({});
637 for my $storage_opt (@storage_options, 'cursor_class') { # @storage_options is declared at the top of the module
638 if(my $value = delete $attrs{$storage_opt}) {
639 $self->$storage_opt($value);
642 for my $sql_maker_opt (qw/limit_dialect quote_char name_sep/) {
643 if(my $opt_val = delete $attrs{$sql_maker_opt}) {
644 $self->_sql_maker_opts->{$sql_maker_opt} = $opt_val;
649 %attrs = () if (ref $args[0] eq 'CODE'); # _connect() never looks past $args[0] in this case
651 $self->_dbi_connect_info([@args, keys %attrs ? \%attrs : ()]);
652 $self->_connect_info;
657 This method is deprecated in favour of setting via L</connect_info>.
662 Arguments: ($subref | $method_name), @extra_coderef_args?
664 Execute the given $subref or $method_name using the new exception-based
665 connection management.
667 The first two arguments will be the storage object that C<dbh_do> was called
668 on and a database handle to use. Any additional arguments will be passed
669 verbatim to the called subref as arguments 2 and onwards.
671 Using this (instead of $self->_dbh or $self->dbh) ensures correct
672 exception handling and reconnection (or failover in future subclasses).
674 Your subref should have no side-effects outside of the database, as
675 there is the potential for your subref to be partially double-executed
676 if the database connection was stale/dysfunctional.
680 my @stuff = $schema->storage->dbh_do(
682 my ($storage, $dbh, @cols) = @_;
683 my $cols = join(q{, }, @cols);
684 $dbh->selectrow_array("SELECT $cols FROM foo");
695 my $dbh = $self->_dbh;
697 return $self->$code($dbh, @_) if $self->{_in_dbh_do}
698 || $self->{transaction_depth};
700 local $self->{_in_dbh_do} = 1;
703 my $want_array = wantarray;
706 $self->_verify_pid if $dbh;
708 $self->_populate_dbh;
713 @result = $self->$code($dbh, @_);
715 elsif(defined $want_array) {
716 $result[0] = $self->$code($dbh, @_);
719 $self->$code($dbh, @_);
724 if(!$exception) { return $want_array ? @result : $result[0] }
726 $self->throw_exception($exception) if $self->connected;
728 # We were not connected - reconnect and retry, but let any
729 # exception fall right through this time
730 $self->_populate_dbh;
731 $self->$code($self->_dbh, @_);
734 # This is basically a blend of dbh_do above and DBIx::Class::Storage::txn_do.
735 # It also informs dbh_do to bypass itself while under the direction of txn_do,
736 # via $self->{_in_dbh_do} (this saves some redundant eval and errorcheck, etc)
741 ref $coderef eq 'CODE' or $self->throw_exception
742 ('$coderef must be a CODE reference');
744 return $coderef->(@_) if $self->{transaction_depth} && ! $self->auto_savepoint;
746 local $self->{_in_dbh_do} = 1;
749 my $want_array = wantarray;
754 $self->_verify_pid if $self->_dbh;
755 $self->_populate_dbh if !$self->_dbh;
759 @result = $coderef->(@_);
761 elsif(defined $want_array) {
762 $result[0] = $coderef->(@_);
771 if(!$exception) { return $want_array ? @result : $result[0] }
773 if($tried++ > 0 || $self->connected) {
774 eval { $self->txn_rollback };
775 my $rollback_exception = $@;
776 if($rollback_exception) {
777 my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION";
778 $self->throw_exception($exception) # propagate nested rollback
779 if $rollback_exception =~ /$exception_class/;
781 $self->throw_exception(
782 "Transaction aborted: ${exception}. "
783 . "Rollback failed: ${rollback_exception}"
786 $self->throw_exception($exception)
789 # We were not connected, and was first try - reconnect and retry
791 $self->_populate_dbh;
797 Our C<disconnect> method also performs a rollback first if the
798 database is not in C<AutoCommit> mode.
805 if( $self->connected ) {
806 my $connection_do = $self->on_disconnect_do;
807 $self->_do_connection_actions($connection_do) if ref($connection_do);
809 $self->_dbh->rollback unless $self->_dbh_autocommit;
810 $self->_dbh->disconnect;
816 =head2 with_deferred_fk_checks
820 =item Arguments: C<$coderef>
822 =item Return Value: The return value of $coderef
826 Storage specific method to run the code ref with FK checks deferred or
827 in MySQL's case disabled entirely.
831 # Storage subclasses should override this
832 sub with_deferred_fk_checks {
833 my ($self, $sub) = @_;
841 if(my $dbh = $self->_dbh) {
842 if(defined $self->_conn_tid && $self->_conn_tid != threads->tid) {
849 return 0 if !$self->_dbh;
851 return ($dbh->FETCH('Active') && $dbh->ping);
857 # handle pid changes correctly
858 # NOTE: assumes $self->_dbh is a valid $dbh
862 return if defined $self->_conn_pid && $self->_conn_pid == $$;
864 $self->_dbh->{InactiveDestroy} = 1;
871 sub ensure_connected {
874 unless ($self->connected) {
875 $self->_populate_dbh;
881 Returns the dbh - a data base handle of class L<DBI>.
888 $self->ensure_connected;
892 sub _sql_maker_args {
895 return ( bindtype=>'columns', array_datatypes => 1, limit_dialect => $self->dbh, %{$self->_sql_maker_opts} );
900 unless ($self->_sql_maker) {
901 my $sql_maker_class = $self->sql_maker_class;
902 $self->_sql_maker($sql_maker_class->new( $self->_sql_maker_args ));
904 return $self->_sql_maker;
911 my @info = @{$self->_dbi_connect_info || []};
912 $self->_dbh($self->_connect(@info));
914 # Always set the transaction depth on connect, since
915 # there is no transaction in progress by definition
916 $self->{transaction_depth} = $self->_dbh_autocommit ? 0 : 1;
918 if(ref $self eq 'DBIx::Class::Storage::DBI') {
919 my $driver = $self->_dbh->{Driver}->{Name};
920 if ($self->load_optional_class("DBIx::Class::Storage::DBI::${driver}")) {
921 bless $self, "DBIx::Class::Storage::DBI::${driver}";
926 $self->_conn_pid($$);
927 $self->_conn_tid(threads->tid) if $INC{'threads.pm'};
929 my $connection_do = $self->on_connect_do;
930 $self->_do_connection_actions($connection_do) if ref($connection_do);
933 sub _do_connection_actions {
935 my $connection_do = shift;
937 if (ref $connection_do eq 'ARRAY') {
938 $self->_do_query($_) foreach @$connection_do;
940 elsif (ref $connection_do eq 'CODE') {
941 $connection_do->($self);
948 my ($self, $action) = @_;
950 if (ref $action eq 'CODE') {
951 $action = $action->($self);
952 $self->_do_query($_) foreach @$action;
955 my @to_run = (ref $action eq 'ARRAY') ? (@$action) : ($action);
956 $self->_query_start(@to_run);
957 $self->_dbh->do(@to_run);
958 $self->_query_end(@to_run);
965 my ($self, @info) = @_;
967 $self->throw_exception("You failed to provide any connection info")
970 my ($old_connect_via, $dbh);
972 if ($INC{'Apache/DBI.pm'} && $ENV{MOD_PERL}) {
973 $old_connect_via = $DBI::connect_via;
974 $DBI::connect_via = 'connect';
978 if(ref $info[0] eq 'CODE') {
982 $dbh = DBI->connect(@info);
985 if($dbh && !$self->unsafe) {
986 my $weak_self = $self;
988 $dbh->{HandleError} = sub {
990 $weak_self->throw_exception("DBI Exception: $_[0]");
993 croak ("DBI Exception: $_[0]");
996 $dbh->{ShowErrorStatement} = 1;
997 $dbh->{RaiseError} = 1;
998 $dbh->{PrintError} = 0;
1002 $DBI::connect_via = $old_connect_via if $old_connect_via;
1004 $self->throw_exception("DBI Connection failed: " . ($@||$DBI::errstr))
1007 $self->_dbh_autocommit($dbh->{AutoCommit});
1013 my ($self, $name) = @_;
1015 $name = $self->_svp_generate_name
1016 unless defined $name;
1018 $self->throw_exception ("You can't use savepoints outside a transaction")
1019 if $self->{transaction_depth} == 0;
1021 $self->throw_exception ("Your Storage implementation doesn't support savepoints")
1022 unless $self->can('_svp_begin');
1024 push @{ $self->{savepoints} }, $name;
1026 $self->debugobj->svp_begin($name) if $self->debug;
1028 return $self->_svp_begin($name);
1032 my ($self, $name) = @_;
1034 $self->throw_exception ("You can't use savepoints outside a transaction")
1035 if $self->{transaction_depth} == 0;
1037 $self->throw_exception ("Your Storage implementation doesn't support savepoints")
1038 unless $self->can('_svp_release');
1040 if (defined $name) {
1041 $self->throw_exception ("Savepoint '$name' does not exist")
1042 unless grep { $_ eq $name } @{ $self->{savepoints} };
1044 # Dig through the stack until we find the one we are releasing. This keeps
1045 # the stack up to date.
1048 do { $svp = pop @{ $self->{savepoints} } } while $svp ne $name;
1050 $name = pop @{ $self->{savepoints} };
1053 $self->debugobj->svp_release($name) if $self->debug;
1055 return $self->_svp_release($name);
1059 my ($self, $name) = @_;
1061 $self->throw_exception ("You can't use savepoints outside a transaction")
1062 if $self->{transaction_depth} == 0;
1064 $self->throw_exception ("Your Storage implementation doesn't support savepoints")
1065 unless $self->can('_svp_rollback');
1067 if (defined $name) {
1068 # If they passed us a name, verify that it exists in the stack
1069 unless(grep({ $_ eq $name } @{ $self->{savepoints} })) {
1070 $self->throw_exception("Savepoint '$name' does not exist!");
1073 # Dig through the stack until we find the one we are releasing. This keeps
1074 # the stack up to date.
1075 while(my $s = pop(@{ $self->{savepoints} })) {
1076 last if($s eq $name);
1078 # Add the savepoint back to the stack, as a rollback doesn't remove the
1079 # named savepoint, only everything after it.
1080 push(@{ $self->{savepoints} }, $name);
1082 # We'll assume they want to rollback to the last savepoint
1083 $name = $self->{savepoints}->[-1];
1086 $self->debugobj->svp_rollback($name) if $self->debug;
1088 return $self->_svp_rollback($name);
1091 sub _svp_generate_name {
1094 return 'savepoint_'.scalar(@{ $self->{'savepoints'} });
1099 $self->ensure_connected();
1100 if($self->{transaction_depth} == 0) {
1101 $self->debugobj->txn_begin()
1103 # this isn't ->_dbh-> because
1104 # we should reconnect on begin_work
1105 # for AutoCommit users
1106 $self->dbh->begin_work;
1107 } elsif ($self->auto_savepoint) {
1110 $self->{transaction_depth}++;
1115 if ($self->{transaction_depth} == 1) {
1116 my $dbh = $self->_dbh;
1117 $self->debugobj->txn_commit()
1120 $self->{transaction_depth} = 0
1121 if $self->_dbh_autocommit;
1123 elsif($self->{transaction_depth} > 1) {
1124 $self->{transaction_depth}--;
1126 if $self->auto_savepoint;
1132 my $dbh = $self->_dbh;
1134 if ($self->{transaction_depth} == 1) {
1135 $self->debugobj->txn_rollback()
1137 $self->{transaction_depth} = 0
1138 if $self->_dbh_autocommit;
1141 elsif($self->{transaction_depth} > 1) {
1142 $self->{transaction_depth}--;
1143 if ($self->auto_savepoint) {
1144 $self->svp_rollback;
1149 die DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION->new;
1154 my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION";
1155 $error =~ /$exception_class/ and $self->throw_exception($error);
1156 # ensure that a failed rollback resets the transaction depth
1157 $self->{transaction_depth} = $self->_dbh_autocommit ? 0 : 1;
1158 $self->throw_exception($error);
1162 # This used to be the top-half of _execute. It was split out to make it
1163 # easier to override in NoBindVars without duping the rest. It takes up
1164 # all of _execute's args, and emits $sql, @bind.
1165 sub _prep_for_execute {
1166 my ($self, $op, $extra_bind, $ident, $args) = @_;
1168 my ($sql, @bind) = $self->sql_maker->$op($ident, @$args);
1170 map { ref $_ eq 'ARRAY' ? $_ : [ '!!dummy', $_ ] } @$extra_bind)
1173 return ($sql, \@bind);
1176 sub _fix_bind_params {
1177 my ($self, @bind) = @_;
1179 ### Turn @bind from something like this:
1180 ### ( [ "artist", 1 ], [ "cdid", 1, 3 ] )
1182 ### ( "'1'", "'1'", "'3'" )
1185 if ( defined( $_ && $_->[1] ) ) {
1186 map { qq{'$_'}; } @{$_}[ 1 .. $#$_ ];
1193 my ( $self, $sql, @bind ) = @_;
1195 if ( $self->debug ) {
1196 @bind = $self->_fix_bind_params(@bind);
1198 $self->debugobj->query_start( $sql, @bind );
1203 my ( $self, $sql, @bind ) = @_;
1205 if ( $self->debug ) {
1206 @bind = $self->_fix_bind_params(@bind);
1207 $self->debugobj->query_end( $sql, @bind );
1212 my ($self, $dbh, $op, $extra_bind, $ident, $bind_attributes, @args) = @_;
1214 if( blessed($ident) && $ident->isa("DBIx::Class::ResultSource") ) {
1215 $ident = $ident->from();
1218 my ($sql, $bind) = $self->_prep_for_execute($op, $extra_bind, $ident, \@args);
1220 $self->_query_start( $sql, @$bind );
1222 my $sth = $self->sth($sql,$op);
1224 my $placeholder_index = 1;
1226 foreach my $bound (@$bind) {
1227 my $attributes = {};
1228 my($column_name, @data) = @$bound;
1230 if ($bind_attributes) {
1231 $attributes = $bind_attributes->{$column_name}
1232 if defined $bind_attributes->{$column_name};
1235 foreach my $data (@data) {
1236 my $ref = ref $data;
1237 $data = $ref && $ref ne 'ARRAY' ? ''.$data : $data; # stringify args (except arrayrefs)
1239 $sth->bind_param($placeholder_index, $data, $attributes);
1240 $placeholder_index++;
1244 # Can this fail without throwing an exception anyways???
1245 my $rv = $sth->execute();
1246 $self->throw_exception($sth->errstr) if !$rv;
1248 $self->_query_end( $sql, @$bind );
1250 return (wantarray ? ($rv, $sth, @$bind) : $rv);
1255 $self->dbh_do('_dbh_execute', @_)
1259 my ($self, $source, $to_insert) = @_;
1261 my $ident = $source->from;
1262 my $bind_attributes = $self->source_bind_attributes($source);
1264 $self->ensure_connected;
1265 foreach my $col ( $source->columns ) {
1266 if ( !defined $to_insert->{$col} ) {
1267 my $col_info = $source->column_info($col);
1269 if ( $col_info->{auto_nextval} ) {
1270 $to_insert->{$col} = $self->_sequence_fetch( 'nextval', $col_info->{sequence} || $self->_dbh_get_autoinc_seq($self->dbh, $source) );
1275 $self->_execute('insert' => [], $source, $bind_attributes, $to_insert);
1280 ## Still not quite perfect, and EXPERIMENTAL
1281 ## Currently it is assumed that all values passed will be "normal", i.e. not
1282 ## scalar refs, or at least, all the same type as the first set, the statement is
1283 ## only prepped once.
1285 my ($self, $source, $cols, $data) = @_;
1287 my $table = $source->from;
1288 @colvalues{@$cols} = (0..$#$cols);
1289 my ($sql, @bind) = $self->sql_maker->insert($table, \%colvalues);
1291 $self->_query_start( $sql, @bind );
1292 my $sth = $self->sth($sql);
1294 # @bind = map { ref $_ ? ''.$_ : $_ } @bind; # stringify args
1296 ## This must be an arrayref, else nothing works!
1298 my $tuple_status = [];
1301 ##print STDERR Dumper( $data, $sql, [@bind] );
1305 ## Get the bind_attributes, if any exist
1306 my $bind_attributes = $self->source_bind_attributes($source);
1308 ## Bind the values and execute
1309 my $placeholder_index = 1;
1311 foreach my $bound (@bind) {
1313 my $attributes = {};
1314 my ($column_name, $data_index) = @$bound;
1316 if( $bind_attributes ) {
1317 $attributes = $bind_attributes->{$column_name}
1318 if defined $bind_attributes->{$column_name};
1321 my @data = map { $_->[$data_index] } @$data;
1323 $sth->bind_param_array( $placeholder_index, [@data], $attributes );
1324 $placeholder_index++;
1326 my $rv = $sth->execute_array({ArrayTupleStatus => $tuple_status});
1327 $self->throw_exception($sth->errstr) if !$rv;
1329 $self->_query_end( $sql, @bind );
1330 return (wantarray ? ($rv, $sth, @bind) : $rv);
1334 my $self = shift @_;
1335 my $source = shift @_;
1336 my $bind_attributes = $self->source_bind_attributes($source);
1338 return $self->_execute('update' => [], $source, $bind_attributes, @_);
1343 my $self = shift @_;
1344 my $source = shift @_;
1346 my $bind_attrs = {}; ## If ever it's needed...
1348 return $self->_execute('delete' => [], $source, $bind_attrs, @_);
1352 my ($self, $ident, $select, $condition, $attrs) = @_;
1353 my $order = $attrs->{order_by};
1355 if (ref $condition eq 'SCALAR') {
1356 my $unwrap = ${$condition};
1357 if ($unwrap =~ s/ORDER BY (.*)$//i) {
1359 $condition = \$unwrap;
1363 my $for = delete $attrs->{for};
1364 my $sql_maker = $self->sql_maker;
1365 local $sql_maker->{for} = $for;
1367 if (exists $attrs->{group_by} || $attrs->{having}) {
1369 group_by => $attrs->{group_by},
1370 having => $attrs->{having},
1371 ($order ? (order_by => $order) : ())
1374 my $bind_attrs = {}; ## Future support
1375 my @args = ('select', $attrs->{bind}, $ident, $bind_attrs, $select, $condition, $order);
1376 if ($attrs->{software_limit} ||
1377 $self->sql_maker->_default_limit_syntax eq "GenericSubQ") {
1378 $attrs->{software_limit} = 1;
1380 $self->throw_exception("rows attribute must be positive if present")
1381 if (defined($attrs->{rows}) && !($attrs->{rows} > 0));
1383 # MySQL actually recommends this approach. I cringe.
1384 $attrs->{rows} = 2**48 if not defined $attrs->{rows} and defined $attrs->{offset};
1385 push @args, $attrs->{rows}, $attrs->{offset};
1388 return $self->_execute(@args);
1391 sub source_bind_attributes {
1392 my ($self, $source) = @_;
1394 my $bind_attributes;
1395 foreach my $column ($source->columns) {
1397 my $data_type = $source->column_info($column)->{data_type} || '';
1398 $bind_attributes->{$column} = $self->bind_attribute_by_data_type($data_type)
1402 return $bind_attributes;
1409 =item Arguments: $ident, $select, $condition, $attrs
1413 Handle a SQL select statement.
1419 my ($ident, $select, $condition, $attrs) = @_;
1420 return $self->cursor_class->new($self, \@_, $attrs);
1425 my ($rv, $sth, @bind) = $self->_select(@_);
1426 my @row = $sth->fetchrow_array;
1427 my @nextrow = $sth->fetchrow_array if @row;
1428 if(@row && @nextrow) {
1429 carp "Query returned more than one row. SQL that returns multiple rows is DEPRECATED for ->find and ->single";
1431 # Need to call finish() to work round broken DBDs
1440 =item Arguments: $sql
1444 Returns a L<DBI> sth (statement handle) for the supplied SQL.
1449 my ($self, $dbh, $sql) = @_;
1451 # 3 is the if_active parameter which avoids active sth re-use
1452 my $sth = $self->disable_sth_caching
1453 ? $dbh->prepare($sql)
1454 : $dbh->prepare_cached($sql, {}, 3);
1456 # XXX You would think RaiseError would make this impossible,
1457 # but apparently that's not true :(
1458 $self->throw_exception($dbh->errstr) if !$sth;
1464 my ($self, $sql) = @_;
1465 $self->dbh_do('_dbh_sth', $sql);
1468 sub _dbh_columns_info_for {
1469 my ($self, $dbh, $table) = @_;
1471 if ($dbh->can('column_info')) {
1474 my ($schema,$tab) = $table =~ /^(.+?)\.(.+)$/ ? ($1,$2) : (undef,$table);
1475 my $sth = $dbh->column_info( undef,$schema, $tab, '%' );
1477 while ( my $info = $sth->fetchrow_hashref() ){
1479 $column_info{data_type} = $info->{TYPE_NAME};
1480 $column_info{size} = $info->{COLUMN_SIZE};
1481 $column_info{is_nullable} = $info->{NULLABLE} ? 1 : 0;
1482 $column_info{default_value} = $info->{COLUMN_DEF};
1483 my $col_name = $info->{COLUMN_NAME};
1484 $col_name =~ s/^\"(.*)\"$/$1/;
1486 $result{$col_name} = \%column_info;
1489 return \%result if !$@ && scalar keys %result;
1493 my $sth = $dbh->prepare($self->sql_maker->select($table, undef, \'1 = 0'));
1495 my @columns = @{$sth->{NAME_lc}};
1496 for my $i ( 0 .. $#columns ){
1498 $column_info{data_type} = $sth->{TYPE}->[$i];
1499 $column_info{size} = $sth->{PRECISION}->[$i];
1500 $column_info{is_nullable} = $sth->{NULLABLE}->[$i] ? 1 : 0;
1502 if ($column_info{data_type} =~ m/^(.*?)\((.*?)\)$/) {
1503 $column_info{data_type} = $1;
1504 $column_info{size} = $2;
1507 $result{$columns[$i]} = \%column_info;
1511 foreach my $col (keys %result) {
1512 my $colinfo = $result{$col};
1513 my $type_num = $colinfo->{data_type};
1515 if(defined $type_num && $dbh->can('type_info')) {
1516 my $type_info = $dbh->type_info($type_num);
1517 $type_name = $type_info->{TYPE_NAME} if $type_info;
1518 $colinfo->{data_type} = $type_name if $type_name;
1525 sub columns_info_for {
1526 my ($self, $table) = @_;
1527 $self->dbh_do('_dbh_columns_info_for', $table);
1530 =head2 last_insert_id
1532 Return the row id of the last insert.
1536 sub _dbh_last_insert_id {
1537 my ($self, $dbh, $source, $col) = @_;
1538 # XXX This is a SQLite-ism as a default... is there a DBI-generic way?
1539 $dbh->func('last_insert_rowid');
1542 sub last_insert_id {
1544 $self->dbh_do('_dbh_last_insert_id', @_);
1549 Returns the database driver name.
1553 sub sqlt_type { shift->dbh->{Driver}->{Name} }
1555 =head2 bind_attribute_by_data_type
1557 Given a datatype from column info, returns a database specific bind
1558 attribute for C<< $dbh->bind_param($val,$attribute) >> or nothing if we will
1559 let the database planner just handle it.
1561 Generally only needed for special case column types, like bytea in postgres.
1565 sub bind_attribute_by_data_type {
1569 =head2 create_ddl_dir
1573 =item Arguments: $schema \@databases, $version, $directory, $preversion, \%sqlt_args
1577 Creates a SQL file based on the Schema, for each of the specified
1578 database types, in the given directory.
1580 By default, C<\%sqlt_args> will have
1582 { add_drop_table => 1, ignore_constraint_names => 1, ignore_index_names => 1 }
1584 merged with the hash passed in. To disable any of those features, pass in a
1585 hashref like the following
1587 { ignore_constraint_names => 0, # ... other options }
1591 sub create_ddl_dir {
1592 my ($self, $schema, $databases, $version, $dir, $preversion, $sqltargs) = @_;
1594 if(!$dir || !-d $dir) {
1595 warn "No directory given, using ./\n";
1598 $databases ||= ['MySQL', 'SQLite', 'PostgreSQL'];
1599 $databases = [ $databases ] if(ref($databases) ne 'ARRAY');
1601 my $schema_version = $schema->schema_version || '1.x';
1602 $version ||= $schema_version;
1605 add_drop_table => 1,
1606 ignore_constraint_names => 1,
1607 ignore_index_names => 1,
1611 $self->throw_exception(q{Can't create a ddl file without SQL::Translator 0.09003: '}
1612 . $self->_check_sqlt_message . q{'})
1613 if !$self->_check_sqlt_version;
1615 my $sqlt = SQL::Translator->new( $sqltargs );
1617 $sqlt->parser('SQL::Translator::Parser::DBIx::Class');
1618 my $sqlt_schema = $sqlt->translate({ data => $schema }) or die $sqlt->error;
1620 foreach my $db (@$databases) {
1622 $sqlt = $self->configure_sqlt($sqlt, $db);
1623 $sqlt->{schema} = $sqlt_schema;
1624 $sqlt->producer($db);
1627 my $filename = $schema->ddl_filename($db, $version, $dir);
1628 if (-e $filename && ($version eq $schema_version )) {
1629 # if we are dumping the current version, overwrite the DDL
1630 warn "Overwriting existing DDL file - $filename";
1634 my $output = $sqlt->translate;
1636 warn("Failed to translate to $db, skipping. (" . $sqlt->error . ")");
1639 if(!open($file, ">$filename")) {
1640 $self->throw_exception("Can't open $filename for writing ($!)");
1643 print $file $output;
1646 next unless ($preversion);
1648 require SQL::Translator::Diff;
1650 my $prefilename = $schema->ddl_filename($db, $preversion, $dir);
1651 if(!-e $prefilename) {
1652 warn("No previous schema file found ($prefilename)");
1656 my $difffile = $schema->ddl_filename($db, $version, $dir, $preversion);
1658 warn("Overwriting existing diff file - $difffile");
1664 my $t = SQL::Translator->new($sqltargs);
1667 $t->parser( $db ) or die $t->error;
1668 $t = $self->configure_sqlt($t, $db);
1669 my $out = $t->translate( $prefilename ) or die $t->error;
1670 $source_schema = $t->schema;
1671 unless ( $source_schema->name ) {
1672 $source_schema->name( $prefilename );
1676 # The "new" style of producers have sane normalization and can support
1677 # diffing a SQL file against a DBIC->SQLT schema. Old style ones don't
1678 # And we have to diff parsed SQL against parsed SQL.
1679 my $dest_schema = $sqlt_schema;
1681 unless ( "SQL::Translator::Producer::$db"->can('preprocess_schema') ) {
1682 my $t = SQL::Translator->new($sqltargs);
1685 $t->parser( $db ) or die $t->error;
1686 $t = $self->configure_sqlt($t, $db);
1687 my $out = $t->translate( $filename ) or die $t->error;
1688 $dest_schema = $t->schema;
1689 $dest_schema->name( $filename )
1690 unless $dest_schema->name;
1693 my $diff = SQL::Translator::Diff::schema_diff($source_schema, $db,
1697 if(!open $file, ">$difffile") {
1698 $self->throw_exception("Can't write to $difffile ($!)");
1706 sub configure_sqlt() {
1709 my $db = shift || $self->sqlt_type;
1710 if ($db eq 'PostgreSQL') {
1711 $tr->quote_table_names(0);
1712 $tr->quote_field_names(0);
1717 =head2 deployment_statements
1721 =item Arguments: $schema, $type, $version, $directory, $sqlt_args
1725 Returns the statements used by L</deploy> and L<DBIx::Class::Schema/deploy>.
1726 The database driver name is given by C<$type>, though the value from
1727 L</sqlt_type> is used if it is not specified.
1729 C<$directory> is used to return statements from files in a previously created
1730 L</create_ddl_dir> directory and is optional. The filenames are constructed
1731 from L<DBIx::Class::Schema/ddl_filename>, the schema name and the C<$version>.
1733 If no C<$directory> is specified then the statements are constructed on the
1734 fly using L<SQL::Translator> and C<$version> is ignored.
1736 See L<SQL::Translator/METHODS> for a list of values for C<$sqlt_args>.
1740 sub deployment_statements {
1741 my ($self, $schema, $type, $version, $dir, $sqltargs) = @_;
1742 # Need to be connected to get the correct sqlt_type
1743 $self->ensure_connected() unless $type;
1744 $type ||= $self->sqlt_type;
1745 $version ||= $schema->schema_version || '1.x';
1747 my $filename = $schema->ddl_filename($type, $dir, $version);
1751 open($file, "<$filename")
1752 or $self->throw_exception("Can't open $filename ($!)");
1755 return join('', @rows);
1758 $self->throw_exception(q{Can't deploy without SQL::Translator 0.09003: '}
1759 . $self->_check_sqlt_message . q{'})
1760 if !$self->_check_sqlt_version;
1762 require SQL::Translator::Parser::DBIx::Class;
1763 eval qq{use SQL::Translator::Producer::${type}};
1764 $self->throw_exception($@) if $@;
1766 # sources needs to be a parser arg, but for simplicty allow at top level
1768 $sqltargs->{parser_args}{sources} = delete $sqltargs->{sources}
1769 if exists $sqltargs->{sources};
1771 my $tr = SQL::Translator->new(%$sqltargs);
1772 SQL::Translator::Parser::DBIx::Class::parse( $tr, $schema );
1773 return "SQL::Translator::Producer::${type}"->can('produce')->($tr);
1777 my ($self, $schema, $type, $sqltargs, $dir) = @_;
1778 foreach my $statement ( $self->deployment_statements($schema, $type, undef, $dir, { no_comments => 1, %{ $sqltargs || {} } } ) ) {
1779 foreach my $line ( split(";\n", $statement)) {
1780 next if($line =~ /^--/);
1782 # next if($line =~ /^DROP/m);
1783 next if($line =~ /^BEGIN TRANSACTION/m);
1784 next if($line =~ /^COMMIT/m);
1785 next if $line =~ /^\s+$/; # skip whitespace only
1786 $self->_query_start($line);
1788 $self->dbh->do($line); # shouldn't be using ->dbh ?
1791 warn qq{$@ (running "${line}")};
1793 $self->_query_end($line);
1798 =head2 datetime_parser
1800 Returns the datetime parser class
1804 sub datetime_parser {
1806 return $self->{datetime_parser} ||= do {
1807 $self->ensure_connected;
1808 $self->build_datetime_parser(@_);
1812 =head2 datetime_parser_type
1814 Defines (returns) the datetime parser class - currently hardwired to
1815 L<DateTime::Format::MySQL>
1819 sub datetime_parser_type { "DateTime::Format::MySQL"; }
1821 =head2 build_datetime_parser
1823 See L</datetime_parser>
1827 sub build_datetime_parser {
1829 my $type = $self->datetime_parser_type(@_);
1831 $self->throw_exception("Couldn't load ${type}: $@") if $@;
1836 my $_check_sqlt_version; # private
1837 my $_check_sqlt_message; # private
1838 sub _check_sqlt_version {
1839 return $_check_sqlt_version if defined $_check_sqlt_version;
1840 eval 'use SQL::Translator "0.09003"';
1841 $_check_sqlt_message = $@ || '';
1842 $_check_sqlt_version = !$@;
1845 sub _check_sqlt_message {
1846 _check_sqlt_version if !defined $_check_sqlt_message;
1847 $_check_sqlt_message;
1851 =head2 is_replicating
1853 A boolean that reports if a particular L<DBIx::Class::Storage::DBI> is set to
1854 replicate from a master database. Default is undef, which is the result
1855 returned by databases that don't support replication.
1859 sub is_replicating {
1864 =head2 lag_behind_master
1866 Returns a number that represents a certain amount of lag behind a master db
1867 when a given storage is replicating. The number is database dependent, but
1868 starts at zero and increases with the amount of lag. Default in undef
1872 sub lag_behind_master {
1878 return if !$self->_dbh;
1887 =head2 DBIx::Class and AutoCommit
1889 DBIx::Class can do some wonderful magic with handling exceptions,
1890 disconnections, and transactions when you use C<< AutoCommit => 1 >>
1891 combined with C<txn_do> for transaction support.
1893 If you set C<< AutoCommit => 0 >> in your connect info, then you are always
1894 in an assumed transaction between commits, and you're telling us you'd
1895 like to manage that manually. A lot of the magic protections offered by
1896 this module will go away. We can't protect you from exceptions due to database
1897 disconnects because we don't know anything about how to restart your
1898 transactions. You're on your own for handling all sorts of exceptional
1899 cases if you choose the C<< AutoCommit => 0 >> path, just as you would
1905 The module defines a set of methods within the DBIC::SQL::Abstract
1906 namespace. These build on L<SQL::Abstract::Limit> to provide the
1907 SQL query functions.
1909 The following methods are extended:-
1923 See L</connect_info> for details.
1927 See L</connect_info> for details.
1931 See L</connect_info> for details.
1937 Matt S. Trout <mst@shadowcatsystems.co.uk>
1939 Andy Grundman <andy@hybridized.org>
1943 You may distribute this code under the same terms as Perl itself.