1 package DBIx::Class::Storage::DBI;
2 # -*- mode: cperl; cperl-indent-level: 2 -*-
7 use base 'DBIx::Class::Storage';
10 use Carp::Clan qw/^DBIx::Class/;
12 use DBIx::Class::Storage::DBI::Cursor;
13 use DBIx::Class::Storage::Statistics;
16 use Data::Dumper::Concise();
18 # what version of sqlt do we require if deploy() without a ddl_dir is invoked
19 # when changing also adjust the corresponding author_require in Makefile.PL
20 my $minimum_sqlt_version = '0.11002';
23 __PACKAGE__->mk_group_accessors('simple' =>
24 qw/_connect_info _dbi_connect_info _dbh _sql_maker _sql_maker_opts _conn_pid
25 _conn_tid transaction_depth _dbh_autocommit _driver_determined savepoints/
28 # the values for these accessors are picked out (and deleted) from
29 # the attribute hashref passed to connect_info
30 my @storage_options = qw/
31 on_connect_call on_disconnect_call on_connect_do on_disconnect_do
32 disable_sth_caching unsafe auto_savepoint
34 __PACKAGE__->mk_group_accessors('simple' => @storage_options);
37 # default cursor class, overridable in connect_info attributes
38 __PACKAGE__->cursor_class('DBIx::Class::Storage::DBI::Cursor');
40 __PACKAGE__->mk_group_accessors('inherited' => qw/sql_maker_class/);
41 __PACKAGE__->sql_maker_class('DBIx::Class::SQLAHacks');
44 # Each of these methods need _determine_driver called before itself
45 # in order to function reliably. This is a purely DRY optimization
46 my @rdbms_specific_methods = qw/
59 for my $meth (@rdbms_specific_methods) {
61 my $orig = __PACKAGE__->can ($meth)
65 no warnings qw/redefine/;
66 *{__PACKAGE__ ."::$meth"} = sub {
67 if (not $_[0]->_driver_determined) {
68 $_[0]->_determine_driver;
69 goto $_[0]->can($meth);
78 DBIx::Class::Storage::DBI - DBI storage handler
82 my $schema = MySchema->connect('dbi:SQLite:my.db');
84 $schema->storage->debug(1);
86 my @stuff = $schema->storage->dbh_do(
88 my ($storage, $dbh, @args) = @_;
89 $dbh->do("DROP TABLE authors");
94 $schema->resultset('Book')->search({
95 written_on => $schema->storage->datetime_parser(DateTime->now)
100 This class represents the connection to an RDBMS via L<DBI>. See
101 L<DBIx::Class::Storage> for general information. This pod only
102 documents DBI-specific methods and behaviors.
109 my $new = shift->next::method(@_);
111 $new->transaction_depth(0);
112 $new->_sql_maker_opts({});
113 $new->{savepoints} = [];
114 $new->{_in_dbh_do} = 0;
115 $new->{_dbh_gen} = 0;
122 This method is normally called by L<DBIx::Class::Schema/connection>, which
123 encapsulates its argument list in an arrayref before passing them here.
125 The argument list may contain:
131 The same 4-element argument set one would normally pass to
132 L<DBI/connect>, optionally followed by
133 L<extra attributes|/DBIx::Class specific connection attributes>
134 recognized by DBIx::Class:
136 $connect_info_args = [ $dsn, $user, $password, \%dbi_attributes?, \%extra_attributes? ];
140 A single code reference which returns a connected
141 L<DBI database handle|DBI/connect> optionally followed by
142 L<extra attributes|/DBIx::Class specific connection attributes> recognized
145 $connect_info_args = [ sub { DBI->connect (...) }, \%extra_attributes? ];
149 A single hashref with all the attributes and the dsn/user/password
152 $connect_info_args = [{
160 $connect_info_args = [{
161 dbh_maker => sub { DBI->connect (...) },
166 This is particularly useful for L<Catalyst> based applications, allowing the
167 following config (L<Config::General> style):
172 dsn dbi:mysql:database=test
179 The C<dsn>/C<user>/C<password> combination can be substituted by the
180 C<dbh_maker> key whose value is a coderef that returns a connected
181 L<DBI database handle|DBI/connect>
185 Please note that the L<DBI> docs recommend that you always explicitly
186 set C<AutoCommit> to either I<0> or I<1>. L<DBIx::Class> further
187 recommends that it be set to I<1>, and that you perform transactions
188 via our L<DBIx::Class::Schema/txn_do> method. L<DBIx::Class> will set it
189 to I<1> if you do not do explicitly set it to zero. This is the default
190 for most DBDs. See L</DBIx::Class and AutoCommit> for details.
192 =head3 DBIx::Class specific connection attributes
194 In addition to the standard L<DBI|DBI/ATTRIBUTES_COMMON_TO_ALL_HANDLES>
195 L<connection|DBI/Database_Handle_Attributes> attributes, DBIx::Class recognizes
196 the following connection options. These options can be mixed in with your other
197 L<DBI> connection attributes, or placed in a seperate hashref
198 (C<\%extra_attributes>) as shown above.
200 Every time C<connect_info> is invoked, any previous settings for
201 these options will be cleared before setting the new ones, regardless of
202 whether any options are specified in the new C<connect_info>.
209 Specifies things to do immediately after connecting or re-connecting to
210 the database. Its value may contain:
216 This contains one SQL statement to execute.
218 =item an array reference
220 This contains SQL statements to execute in order. Each element contains
221 a string or a code reference that returns a string.
223 =item a code reference
225 This contains some code to execute. Unlike code references within an
226 array reference, its return value is ignored.
230 =item on_disconnect_do
232 Takes arguments in the same form as L</on_connect_do> and executes them
233 immediately before disconnecting from the database.
235 Note, this only runs if you explicitly call L</disconnect> on the
238 =item on_connect_call
240 A more generalized form of L</on_connect_do> that calls the specified
241 C<connect_call_METHOD> methods in your storage driver.
243 on_connect_do => 'select 1'
247 on_connect_call => [ [ do_sql => 'select 1' ] ]
249 Its values may contain:
255 Will call the C<connect_call_METHOD> method.
257 =item a code reference
259 Will execute C<< $code->($storage) >>
261 =item an array reference
263 Each value can be a method name or code reference.
265 =item an array of arrays
267 For each array, the first item is taken to be the C<connect_call_> method name
268 or code reference, and the rest are parameters to it.
272 Some predefined storage methods you may use:
278 Executes a SQL string or a code reference that returns a SQL string. This is
279 what L</on_connect_do> and L</on_disconnect_do> use.
287 Will execute the scalar as SQL.
291 Taken to be arguments to L<DBI/do>, the SQL string optionally followed by the
292 attributes hashref and bind values.
294 =item a code reference
296 Will execute C<< $code->($storage) >> and execute the return array refs as
303 Execute any statements necessary to initialize the database session to return
304 and accept datetime/timestamp values used with
305 L<DBIx::Class::InflateColumn::DateTime>.
307 Only necessary for some databases, see your specific storage driver for
308 implementation details.
312 =item on_disconnect_call
314 Takes arguments in the same form as L</on_connect_call> and executes them
315 immediately before disconnecting from the database.
317 Calls the C<disconnect_call_METHOD> methods as opposed to the
318 C<connect_call_METHOD> methods called by L</on_connect_call>.
320 Note, this only runs if you explicitly call L</disconnect> on the
323 =item disable_sth_caching
325 If set to a true value, this option will disable the caching of
326 statement handles via L<DBI/prepare_cached>.
330 Sets the limit dialect. This is useful for JDBC-bridge among others
331 where the remote SQL-dialect cannot be determined by the name of the
332 driver alone. See also L<SQL::Abstract::Limit>.
336 Specifies what characters to use to quote table and column names. If
337 you use this you will want to specify L</name_sep> as well.
339 C<quote_char> expects either a single character, in which case is it
340 is placed on either side of the table/column name, or an arrayref of length
341 2 in which case the table/column name is placed between the elements.
343 For example under MySQL you should use C<< quote_char => '`' >>, and for
344 SQL Server you should use C<< quote_char => [qw/[ ]/] >>.
348 This only needs to be used in conjunction with C<quote_char>, and is used to
349 specify the charecter that seperates elements (schemas, tables, columns) from
350 each other. In most cases this is simply a C<.>.
352 The consequences of not supplying this value is that L<SQL::Abstract>
353 will assume DBIx::Class' uses of aliases to be complete column
354 names. The output will look like I<"me.name"> when it should actually
359 This Storage driver normally installs its own C<HandleError>, sets
360 C<RaiseError> and C<ShowErrorStatement> on, and sets C<PrintError> off on
361 all database handles, including those supplied by a coderef. It does this
362 so that it can have consistent and useful error behavior.
364 If you set this option to a true value, Storage will not do its usual
365 modifications to the database handle's attributes, and instead relies on
366 the settings in your connect_info DBI options (or the values you set in
367 your connection coderef, in the case that you are connecting via coderef).
369 Note that your custom settings can cause Storage to malfunction,
370 especially if you set a C<HandleError> handler that suppresses exceptions
371 and/or disable C<RaiseError>.
375 If this option is true, L<DBIx::Class> will use savepoints when nesting
376 transactions, making it possible to recover from failure in the inner
377 transaction without having to abort all outer transactions.
381 Use this argument to supply a cursor class other than the default
382 L<DBIx::Class::Storage::DBI::Cursor>.
386 Some real-life examples of arguments to L</connect_info> and
387 L<DBIx::Class::Schema/connect>
389 # Simple SQLite connection
390 ->connect_info([ 'dbi:SQLite:./foo.db' ]);
393 ->connect_info([ sub { DBI->connect(...) } ]);
395 # Connect via subref in hashref
397 dbh_maker => sub { DBI->connect(...) },
398 on_connect_do => 'alter session ...',
401 # A bit more complicated
408 { quote_char => q{"}, name_sep => q{.} },
412 # Equivalent to the previous example
418 { AutoCommit => 1, quote_char => q{"}, name_sep => q{.} },
422 # Same, but with hashref as argument
423 # See parse_connect_info for explanation
426 dsn => 'dbi:Pg:dbname=foo',
428 password => 'my_pg_password',
435 # Subref + DBIx::Class-specific connection options
438 sub { DBI->connect(...) },
442 on_connect_do => ['SET search_path TO myschema,otherschema,public'],
443 disable_sth_caching => 1,
453 my ($self, $info_arg) = @_;
455 return $self->_connect_info if !$info_arg;
457 my @args = @$info_arg; # take a shallow copy for further mutilation
458 $self->_connect_info([@args]); # copy for _connect_info
461 # combine/pre-parse arguments depending on invocation style
464 if (ref $args[0] eq 'CODE') { # coderef with optional \%extra_attributes
465 %attrs = %{ $args[1] || {} };
468 elsif (ref $args[0] eq 'HASH') { # single hashref (i.e. Catalyst config)
469 %attrs = %{$args[0]};
471 if (my $code = delete $attrs{dbh_maker}) {
474 my @ignored = grep { delete $attrs{$_} } (qw/dsn user password/);
477 'Attribute(s) %s in connect_info were ignored, as they can not be applied '
478 . "to the result of 'dbh_maker'",
480 join (', ', map { "'$_'" } (@ignored) ),
485 @args = delete @attrs{qw/dsn user password/};
488 else { # otherwise assume dsn/user/password + \%attrs + \%extra_attrs
490 % { $args[3] || {} },
491 % { $args[4] || {} },
493 @args = @args[0,1,2];
496 # Kill sql_maker/_sql_maker_opts, so we get a fresh one with only
497 # the new set of options
498 $self->_sql_maker(undef);
499 $self->_sql_maker_opts({});
502 for my $storage_opt (@storage_options, 'cursor_class') { # @storage_options is declared at the top of the module
503 if(my $value = delete $attrs{$storage_opt}) {
504 $self->$storage_opt($value);
507 for my $sql_maker_opt (qw/limit_dialect quote_char name_sep/) {
508 if(my $opt_val = delete $attrs{$sql_maker_opt}) {
509 $self->_sql_maker_opts->{$sql_maker_opt} = $opt_val;
514 if (ref $args[0] eq 'CODE') {
515 # _connect() never looks past $args[0] in this case
519 %{ $self->_default_dbi_connect_attributes || {} },
524 $self->_dbi_connect_info([@args, keys %attrs ? \%attrs : ()]);
525 $self->_connect_info;
528 sub _default_dbi_connect_attributes {
538 This method is deprecated in favour of setting via L</connect_info>.
542 =head2 on_disconnect_do
544 This method is deprecated in favour of setting via L</connect_info>.
548 sub _parse_connect_do {
549 my ($self, $type) = @_;
551 my $val = $self->$type;
552 return () if not defined $val;
557 push @res, [ 'do_sql', $val ];
558 } elsif (ref($val) eq 'CODE') {
560 } elsif (ref($val) eq 'ARRAY') {
561 push @res, map { [ 'do_sql', $_ ] } @$val;
563 $self->throw_exception("Invalid type for $type: ".ref($val));
571 Arguments: ($subref | $method_name), @extra_coderef_args?
573 Execute the given $subref or $method_name using the new exception-based
574 connection management.
576 The first two arguments will be the storage object that C<dbh_do> was called
577 on and a database handle to use. Any additional arguments will be passed
578 verbatim to the called subref as arguments 2 and onwards.
580 Using this (instead of $self->_dbh or $self->dbh) ensures correct
581 exception handling and reconnection (or failover in future subclasses).
583 Your subref should have no side-effects outside of the database, as
584 there is the potential for your subref to be partially double-executed
585 if the database connection was stale/dysfunctional.
589 my @stuff = $schema->storage->dbh_do(
591 my ($storage, $dbh, @cols) = @_;
592 my $cols = join(q{, }, @cols);
593 $dbh->selectrow_array("SELECT $cols FROM foo");
604 my $dbh = $self->_get_dbh;
606 return $self->$code($dbh, @_) if $self->{_in_dbh_do}
607 || $self->{transaction_depth};
609 local $self->{_in_dbh_do} = 1;
612 my $want_array = wantarray;
617 @result = $self->$code($dbh, @_);
619 elsif(defined $want_array) {
620 $result[0] = $self->$code($dbh, @_);
623 $self->$code($dbh, @_);
627 # ->connected might unset $@ - copy
629 if(!$exception) { return $want_array ? @result : $result[0] }
631 $self->throw_exception($exception) if $self->connected;
633 # We were not connected - reconnect and retry, but let any
634 # exception fall right through this time
635 carp "Retrying $code after catching disconnected exception: $exception"
636 if $ENV{DBIC_DBIRETRY_DEBUG};
637 $self->_populate_dbh;
638 $self->$code($self->_dbh, @_);
641 # This is basically a blend of dbh_do above and DBIx::Class::Storage::txn_do.
642 # It also informs dbh_do to bypass itself while under the direction of txn_do,
643 # via $self->{_in_dbh_do} (this saves some redundant eval and errorcheck, etc)
648 ref $coderef eq 'CODE' or $self->throw_exception
649 ('$coderef must be a CODE reference');
651 return $coderef->(@_) if $self->{transaction_depth} && ! $self->auto_savepoint;
653 local $self->{_in_dbh_do} = 1;
656 my $want_array = wantarray;
665 @result = $coderef->(@_);
667 elsif(defined $want_array) {
668 $result[0] = $coderef->(@_);
676 # ->connected might unset $@ - copy
678 if(!$exception) { return $want_array ? @result : $result[0] }
680 if($tried++ || $self->connected) {
681 eval { $self->txn_rollback };
682 my $rollback_exception = $@;
683 if($rollback_exception) {
684 my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION";
685 $self->throw_exception($exception) # propagate nested rollback
686 if $rollback_exception =~ /$exception_class/;
688 $self->throw_exception(
689 "Transaction aborted: ${exception}. "
690 . "Rollback failed: ${rollback_exception}"
693 $self->throw_exception($exception)
696 # We were not connected, and was first try - reconnect and retry
698 carp "Retrying $coderef after catching disconnected exception: $exception"
699 if $ENV{DBIC_DBIRETRY_DEBUG};
700 $self->_populate_dbh;
706 Our C<disconnect> method also performs a rollback first if the
707 database is not in C<AutoCommit> mode.
717 push @actions, ( $self->on_disconnect_call || () );
718 push @actions, $self->_parse_connect_do ('on_disconnect_do');
720 $self->_do_connection_actions(disconnect_call_ => $_) for @actions;
722 $self->_dbh_rollback unless $self->_dbh_autocommit;
724 $self->_dbh->disconnect;
730 =head2 with_deferred_fk_checks
734 =item Arguments: C<$coderef>
736 =item Return Value: The return value of $coderef
740 Storage specific method to run the code ref with FK checks deferred or
741 in MySQL's case disabled entirely.
745 # Storage subclasses should override this
746 sub with_deferred_fk_checks {
747 my ($self, $sub) = @_;
755 =item Arguments: none
757 =item Return Value: 1|0
761 Verifies that the the current database handle is active and ready to execute
762 an SQL statement (i.e. the connection did not get stale, server is still
763 answering, etc.) This method is used internally by L</dbh>.
769 return 0 unless $self->_seems_connected;
772 local $self->_dbh->{RaiseError} = 1;
777 sub _seems_connected {
780 my $dbh = $self->_dbh
783 if(defined $self->_conn_tid && $self->_conn_tid != threads->tid) {
790 return 0 if !$self->_dbh;
793 return $dbh->FETCH('Active');
799 my $dbh = $self->_dbh or return 0;
804 # handle pid changes correctly
805 # NOTE: assumes $self->_dbh is a valid $dbh
809 return if defined $self->_conn_pid && $self->_conn_pid == $$;
811 $self->_dbh->{InactiveDestroy} = 1;
818 sub ensure_connected {
821 unless ($self->connected) {
822 $self->_populate_dbh;
828 Returns a C<$dbh> - a data base handle of class L<DBI>. The returned handle
829 is guaranteed to be healthy by implicitly calling L</connected>, and if
830 necessary performing a reconnection before returning. Keep in mind that this
831 is very B<expensive> on some database engines. Consider using L<dbh_do>
839 if (not $self->_dbh) {
840 $self->_populate_dbh;
842 $self->ensure_connected;
847 # this is the internal "get dbh or connect (don't check)" method
850 $self->_verify_pid if $self->_dbh;
851 $self->_populate_dbh unless $self->_dbh;
855 sub _sql_maker_args {
860 array_datatypes => 1,
861 limit_dialect => $self->_get_dbh,
862 %{$self->_sql_maker_opts}
868 unless ($self->_sql_maker) {
869 my $sql_maker_class = $self->sql_maker_class;
870 $self->ensure_class_loaded ($sql_maker_class);
871 $self->_sql_maker($sql_maker_class->new( $self->_sql_maker_args ));
873 return $self->_sql_maker;
876 # nothing to do by default
883 my @info = @{$self->_dbi_connect_info || []};
884 $self->_dbh(undef); # in case ->connected failed we might get sent here
885 $self->_dbh($self->_connect(@info));
887 $self->_conn_pid($$);
888 $self->_conn_tid(threads->tid) if $INC{'threads.pm'};
890 $self->_determine_driver;
892 # Always set the transaction depth on connect, since
893 # there is no transaction in progress by definition
894 $self->{transaction_depth} = $self->_dbh_autocommit ? 0 : 1;
896 $self->_run_connection_actions unless $self->{_in_determine_driver};
899 sub _run_connection_actions {
903 push @actions, ( $self->on_connect_call || () );
904 push @actions, $self->_parse_connect_do ('on_connect_do');
906 $self->_do_connection_actions(connect_call_ => $_) for @actions;
909 sub _determine_driver {
912 if ((not $self->_driver_determined) && (not $self->{_in_determine_driver})) {
913 my $started_connected = 0;
914 local $self->{_in_determine_driver} = 1;
916 if (ref($self) eq __PACKAGE__) {
918 if ($self->_dbh) { # we are connected
919 $driver = $self->_dbh->{Driver}{Name};
920 $started_connected = 1;
922 # if connect_info is a CODEREF, we have no choice but to connect
923 if (ref $self->_dbi_connect_info->[0] &&
924 Scalar::Util::reftype($self->_dbi_connect_info->[0]) eq 'CODE') {
925 $self->_populate_dbh;
926 $driver = $self->_dbh->{Driver}{Name};
929 # try to use dsn to not require being connected, the driver may still
930 # force a connection in _rebless to determine version
931 ($driver) = $self->_dbi_connect_info->[0] =~ /dbi:([^:]+):/i;
935 my $storage_class = "DBIx::Class::Storage::DBI::${driver}";
936 if ($self->load_optional_class($storage_class)) {
937 mro::set_mro($storage_class, 'c3');
938 bless $self, $storage_class;
943 $self->_driver_determined(1);
945 $self->_init; # run driver-specific initializations
947 $self->_run_connection_actions
948 if !$started_connected && defined $self->_dbh;
952 sub _do_connection_actions {
954 my $method_prefix = shift;
957 if (not ref($call)) {
958 my $method = $method_prefix . $call;
960 } elsif (ref($call) eq 'CODE') {
962 } elsif (ref($call) eq 'ARRAY') {
963 if (ref($call->[0]) ne 'ARRAY') {
964 $self->_do_connection_actions($method_prefix, $_) for @$call;
966 $self->_do_connection_actions($method_prefix, @$_) for @$call;
969 $self->throw_exception (sprintf ("Don't know how to process conection actions of type '%s'", ref($call)) );
975 sub connect_call_do_sql {
977 $self->_do_query(@_);
980 sub disconnect_call_do_sql {
982 $self->_do_query(@_);
985 # override in db-specific backend when necessary
986 sub connect_call_datetime_setup { 1 }
989 my ($self, $action) = @_;
991 if (ref $action eq 'CODE') {
992 $action = $action->($self);
993 $self->_do_query($_) foreach @$action;
996 # Most debuggers expect ($sql, @bind), so we need to exclude
997 # the attribute hash which is the second argument to $dbh->do
998 # furthermore the bind values are usually to be presented
999 # as named arrayref pairs, so wrap those here too
1000 my @do_args = (ref $action eq 'ARRAY') ? (@$action) : ($action);
1001 my $sql = shift @do_args;
1002 my $attrs = shift @do_args;
1003 my @bind = map { [ undef, $_ ] } @do_args;
1005 $self->_query_start($sql, @bind);
1006 $self->_get_dbh->do($sql, $attrs, @do_args);
1007 $self->_query_end($sql, @bind);
1014 my ($self, @info) = @_;
1016 $self->throw_exception("You failed to provide any connection info")
1019 my ($old_connect_via, $dbh);
1021 if ($INC{'Apache/DBI.pm'} && $ENV{MOD_PERL}) {
1022 $old_connect_via = $DBI::connect_via;
1023 $DBI::connect_via = 'connect';
1027 if(ref $info[0] eq 'CODE') {
1031 $dbh = DBI->connect(@info);
1034 if($dbh && !$self->unsafe) {
1035 my $weak_self = $self;
1036 Scalar::Util::weaken($weak_self);
1037 $dbh->{HandleError} = sub {
1039 $weak_self->throw_exception("DBI Exception: $_[0]");
1042 # the handler may be invoked by something totally out of
1044 croak ("DBI Exception: $_[0]");
1047 $dbh->{ShowErrorStatement} = 1;
1048 $dbh->{RaiseError} = 1;
1049 $dbh->{PrintError} = 0;
1053 $DBI::connect_via = $old_connect_via if $old_connect_via;
1055 $self->throw_exception("DBI Connection failed: " . ($@||$DBI::errstr))
1058 $self->_dbh_autocommit($dbh->{AutoCommit});
1064 my ($self, $name) = @_;
1066 $name = $self->_svp_generate_name
1067 unless defined $name;
1069 $self->throw_exception ("You can't use savepoints outside a transaction")
1070 if $self->{transaction_depth} == 0;
1072 $self->throw_exception ("Your Storage implementation doesn't support savepoints")
1073 unless $self->can('_svp_begin');
1075 push @{ $self->{savepoints} }, $name;
1077 $self->debugobj->svp_begin($name) if $self->debug;
1079 return $self->_svp_begin($name);
1083 my ($self, $name) = @_;
1085 $self->throw_exception ("You can't use savepoints outside a transaction")
1086 if $self->{transaction_depth} == 0;
1088 $self->throw_exception ("Your Storage implementation doesn't support savepoints")
1089 unless $self->can('_svp_release');
1091 if (defined $name) {
1092 $self->throw_exception ("Savepoint '$name' does not exist")
1093 unless grep { $_ eq $name } @{ $self->{savepoints} };
1095 # Dig through the stack until we find the one we are releasing. This keeps
1096 # the stack up to date.
1099 do { $svp = pop @{ $self->{savepoints} } } while $svp ne $name;
1101 $name = pop @{ $self->{savepoints} };
1104 $self->debugobj->svp_release($name) if $self->debug;
1106 return $self->_svp_release($name);
1110 my ($self, $name) = @_;
1112 $self->throw_exception ("You can't use savepoints outside a transaction")
1113 if $self->{transaction_depth} == 0;
1115 $self->throw_exception ("Your Storage implementation doesn't support savepoints")
1116 unless $self->can('_svp_rollback');
1118 if (defined $name) {
1119 # If they passed us a name, verify that it exists in the stack
1120 unless(grep({ $_ eq $name } @{ $self->{savepoints} })) {
1121 $self->throw_exception("Savepoint '$name' does not exist!");
1124 # Dig through the stack until we find the one we are releasing. This keeps
1125 # the stack up to date.
1126 while(my $s = pop(@{ $self->{savepoints} })) {
1127 last if($s eq $name);
1129 # Add the savepoint back to the stack, as a rollback doesn't remove the
1130 # named savepoint, only everything after it.
1131 push(@{ $self->{savepoints} }, $name);
1133 # We'll assume they want to rollback to the last savepoint
1134 $name = $self->{savepoints}->[-1];
1137 $self->debugobj->svp_rollback($name) if $self->debug;
1139 return $self->_svp_rollback($name);
1142 sub _svp_generate_name {
1145 return 'savepoint_'.scalar(@{ $self->{'savepoints'} });
1150 if($self->{transaction_depth} == 0) {
1151 $self->debugobj->txn_begin()
1153 $self->_dbh_begin_work;
1155 elsif ($self->auto_savepoint) {
1158 $self->{transaction_depth}++;
1161 sub _dbh_begin_work {
1164 # if the user is utilizing txn_do - good for him, otherwise we need to
1165 # ensure that the $dbh is healthy on BEGIN.
1166 # We do this via ->dbh_do instead of ->dbh, so that the ->dbh "ping"
1167 # will be replaced by a failure of begin_work itself (which will be
1168 # then retried on reconnect)
1169 if ($self->{_in_dbh_do}) {
1170 $self->_dbh->begin_work;
1172 $self->dbh_do(sub { $_[1]->begin_work });
1178 if ($self->{transaction_depth} == 1) {
1179 $self->debugobj->txn_commit()
1182 $self->{transaction_depth} = 0
1183 if $self->_dbh_autocommit;
1185 elsif($self->{transaction_depth} > 1) {
1186 $self->{transaction_depth}--;
1188 if $self->auto_savepoint;
1194 my $dbh = $self->_dbh
1195 or $self->throw_exception('cannot COMMIT on a disconnected handle');
1201 my $dbh = $self->_dbh;
1203 if ($self->{transaction_depth} == 1) {
1204 $self->debugobj->txn_rollback()
1206 $self->{transaction_depth} = 0
1207 if $self->_dbh_autocommit;
1208 $self->_dbh_rollback;
1210 elsif($self->{transaction_depth} > 1) {
1211 $self->{transaction_depth}--;
1212 if ($self->auto_savepoint) {
1213 $self->svp_rollback;
1218 die DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION->new;
1223 my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION";
1224 $error =~ /$exception_class/ and $self->throw_exception($error);
1225 # ensure that a failed rollback resets the transaction depth
1226 $self->{transaction_depth} = $self->_dbh_autocommit ? 0 : 1;
1227 $self->throw_exception($error);
1233 my $dbh = $self->_dbh
1234 or $self->throw_exception('cannot ROLLBACK on a disconnected handle');
1238 # This used to be the top-half of _execute. It was split out to make it
1239 # easier to override in NoBindVars without duping the rest. It takes up
1240 # all of _execute's args, and emits $sql, @bind.
1241 sub _prep_for_execute {
1242 my ($self, $op, $extra_bind, $ident, $args) = @_;
1244 if( Scalar::Util::blessed($ident) && $ident->isa("DBIx::Class::ResultSource") ) {
1245 $ident = $ident->from();
1248 my ($sql, @bind) = $self->sql_maker->$op($ident, @$args);
1251 map { ref $_ eq 'ARRAY' ? $_ : [ '!!dummy', $_ ] } @$extra_bind)
1253 return ($sql, \@bind);
1257 sub _fix_bind_params {
1258 my ($self, @bind) = @_;
1260 ### Turn @bind from something like this:
1261 ### ( [ "artist", 1 ], [ "cdid", 1, 3 ] )
1263 ### ( "'1'", "'1'", "'3'" )
1266 if ( defined( $_ && $_->[1] ) ) {
1267 map { qq{'$_'}; } @{$_}[ 1 .. $#$_ ];
1274 my ( $self, $sql, @bind ) = @_;
1276 if ( $self->debug ) {
1277 @bind = $self->_fix_bind_params(@bind);
1279 $self->debugobj->query_start( $sql, @bind );
1284 my ( $self, $sql, @bind ) = @_;
1286 if ( $self->debug ) {
1287 @bind = $self->_fix_bind_params(@bind);
1288 $self->debugobj->query_end( $sql, @bind );
1293 my ($self, $dbh, $op, $extra_bind, $ident, $bind_attributes, @args) = @_;
1295 my ($sql, $bind) = $self->_prep_for_execute($op, $extra_bind, $ident, \@args);
1297 $self->_query_start( $sql, @$bind );
1299 my $sth = $self->sth($sql,$op);
1301 my $placeholder_index = 1;
1303 foreach my $bound (@$bind) {
1304 my $attributes = {};
1305 my($column_name, @data) = @$bound;
1307 if ($bind_attributes) {
1308 $attributes = $bind_attributes->{$column_name}
1309 if defined $bind_attributes->{$column_name};
1312 foreach my $data (@data) {
1313 my $ref = ref $data;
1314 $data = $ref && $ref ne 'ARRAY' ? ''.$data : $data; # stringify args (except arrayrefs)
1316 $sth->bind_param($placeholder_index, $data, $attributes);
1317 $placeholder_index++;
1321 # Can this fail without throwing an exception anyways???
1322 my $rv = $sth->execute();
1323 $self->throw_exception($sth->errstr) if !$rv;
1325 $self->_query_end( $sql, @$bind );
1327 return (wantarray ? ($rv, $sth, @$bind) : $rv);
1332 $self->dbh_do('_dbh_execute', @_); # retry over disconnects
1336 my ($self, $source, $to_insert) = @_;
1338 my $ident = $source->from;
1339 my $bind_attributes = $self->source_bind_attributes($source);
1341 my $updated_cols = {};
1343 foreach my $col ( $source->columns ) {
1344 if ( !defined $to_insert->{$col} ) {
1345 my $col_info = $source->column_info($col);
1347 if ( $col_info->{auto_nextval} ) {
1348 $updated_cols->{$col} = $to_insert->{$col} = $self->_sequence_fetch(
1350 $col_info->{sequence} ||
1351 $self->_dbh_get_autoinc_seq($self->_get_dbh, $source)
1357 $self->_execute('insert' => [], $source, $bind_attributes, $to_insert);
1359 return $updated_cols;
1362 ## Still not quite perfect, and EXPERIMENTAL
1363 ## Currently it is assumed that all values passed will be "normal", i.e. not
1364 ## scalar refs, or at least, all the same type as the first set, the statement is
1365 ## only prepped once.
1367 my ($self, $source, $cols, $data) = @_;
1370 @colvalues{@$cols} = (0..$#$cols);
1372 for my $i (0..$#$cols) {
1373 my $first_val = $data->[0][$i];
1374 next unless ref $first_val eq 'SCALAR';
1376 $colvalues{ $cols->[$i] } = $first_val;
1379 # check for bad data and stringify stringifiable objects
1380 my $bad_slice = sub {
1381 my ($msg, $col_idx, $slice_idx) = @_;
1382 $self->throw_exception(sprintf "%s for column '%s' in populate slice:\n%s",
1386 local $Data::Dumper::Maxdepth = 1; # don't dump objects, if any
1387 Data::Dumper::Concise::Dumper({
1388 map { $cols->[$_] => $data->[$slice_idx][$_] } (0 .. $#$cols)
1394 for my $datum_idx (0..$#$data) {
1395 my $datum = $data->[$datum_idx];
1397 for my $col_idx (0..$#$cols) {
1398 my $val = $datum->[$col_idx];
1399 my $sqla_bind = $colvalues{ $cols->[$col_idx] };
1400 my $is_literal_sql = (ref $sqla_bind) eq 'SCALAR';
1402 if ($is_literal_sql) {
1404 $bad_slice->('bind found where literal SQL expected', $col_idx, $datum_idx);
1406 elsif ((my $reftype = ref $val) ne 'SCALAR') {
1407 $bad_slice->("$reftype reference found where literal SQL expected",
1408 $col_idx, $datum_idx);
1410 elsif ($$val ne $$sqla_bind){
1411 $bad_slice->("inconsistent literal SQL value, expecting: '$$sqla_bind'",
1412 $col_idx, $datum_idx);
1415 elsif (my $reftype = ref $val) {
1417 if (overload::Method($val, '""')) {
1418 $datum->[$col_idx] = "".$val;
1421 $bad_slice->("$reftype reference found where bind expected",
1422 $col_idx, $datum_idx);
1428 my ($sql, $bind) = $self->_prep_for_execute (
1429 'insert', undef, $source, [\%colvalues]
1433 my $empty_bind = 1 if (not @bind) &&
1434 (grep { ref $_ eq 'SCALAR' } values %colvalues) == @$cols;
1436 if ((not @bind) && (not $empty_bind)) {
1437 $self->throw_exception(
1438 'Cannot insert_bulk without support for placeholders'
1442 $self->_query_start( $sql, ['__BULK__'] );
1443 my $sth = $self->sth($sql);
1447 # bind_param_array doesn't work if there are no binds
1448 $self->_dbh_execute_inserts_with_no_binds( $sth, scalar @$data );
1451 # @bind = map { ref $_ ? ''.$_ : $_ } @bind; # stringify args
1452 $self->_execute_array( $source, $sth, \@bind, $cols, $data );
1456 $self->_query_end( $sql, ['__BULK__'] );
1458 return (wantarray ? ($rv, $sth, @bind) : $rv);
1461 sub _execute_array {
1462 my ($self, $source, $sth, $bind, $cols, $data, @extra) = @_;
1464 my $guard = $self->txn_scope_guard unless $self->{transaction_depth} != 0;
1466 ## This must be an arrayref, else nothing works!
1467 my $tuple_status = [];
1469 ## Get the bind_attributes, if any exist
1470 my $bind_attributes = $self->source_bind_attributes($source);
1472 ## Bind the values and execute
1473 my $placeholder_index = 1;
1475 foreach my $bound (@$bind) {
1477 my $attributes = {};
1478 my ($column_name, $data_index) = @$bound;
1480 if( $bind_attributes ) {
1481 $attributes = $bind_attributes->{$column_name}
1482 if defined $bind_attributes->{$column_name};
1485 my @data = map { $_->[$data_index] } @$data;
1487 $sth->bind_param_array( $placeholder_index, [@data], $attributes );
1488 $placeholder_index++;
1492 $self->_dbh_execute_array($sth, $tuple_status, @extra);
1494 my $err = $@ || $sth->errstr;
1496 # Statement must finish even if there was an exception.
1497 eval { $sth->finish };
1498 $err = $@ unless $err;
1502 ++$i while $i <= $#$tuple_status && !ref $tuple_status->[$i];
1504 $self->throw_exception("Unexpected populate error: $err")
1505 if ($i > $#$tuple_status);
1507 $self->throw_exception(sprintf "%s for populate slice:\n%s",
1508 ($tuple_status->[$i][1] || $err),
1509 Data::Dumper::Concise::Dumper({
1510 map { $cols->[$_] => $data->[$i][$_] } (0 .. $#$cols)
1515 $guard->commit if $guard;
1520 sub _dbh_execute_array {
1521 my ($self, $sth, $tuple_status, @extra) = @_;
1523 return $sth->execute_array({ArrayTupleStatus => $tuple_status});
1526 sub _dbh_execute_inserts_with_no_binds {
1527 my ($self, $sth, $count) = @_;
1529 my $guard = $self->txn_scope_guard unless $self->{transaction_depth} != 0;
1532 my $dbh = $self->_get_dbh;
1533 local $dbh->{RaiseError} = 1;
1534 local $dbh->{PrintError} = 0;
1536 $sth->execute foreach 1..$count;
1540 # Make sure statement is finished even if there was an exception.
1541 eval { $sth->finish };
1542 $exception = $@ unless $exception;
1544 $self->throw_exception($exception) if $exception;
1546 $guard->commit if $guard;
1552 my ($self, $source, $data, $where, @args) = @_;
1554 my $bind_attrs = $self->source_bind_attributes($source);
1555 $where = $self->_strip_cond_qualifiers ($where);
1557 return $self->_execute('update' => [], $source, $bind_attrs, $data, $where, @args);
1562 my ($self, $source, $where, @args) = @_;
1564 my $bind_attrs = $self->source_bind_attributes($source);
1565 $where = $self->_strip_cond_qualifiers ($where);
1567 return $self->_execute('delete' => [], $source, $bind_attrs, $where, @args);
1570 sub _strip_cond_qualifiers {
1571 my ($self, $where) = @_;
1573 my $sqlmaker = $self->sql_maker;
1574 my ($sql, @bind) = $sqlmaker->_recurse_where($where);
1575 return undef unless $sql;
1577 my ($qquot, $qsep) = map { quotemeta $_ } ( ($sqlmaker->quote_char||''), ($sqlmaker->name_sep||'.') );
1578 $sql =~ s/ (?: $qquot [\w\-]+ $qquot | [\w\-]+ ) $qsep //gx;
1580 return \[$sql, @bind];
1583 # We were sent here because the $rs contains a complex search
1584 # which will require a subquery to select the correct rows
1585 # (i.e. joined or limited resultsets)
1587 # Genarating a single PK column subquery is trivial and supported
1588 # by all RDBMS. However if we have a multicolumn PK, things get ugly.
1589 # Look at _multipk_update_delete()
1590 sub _subq_update_delete {
1592 my ($rs, $op, $values) = @_;
1594 my $rsrc = $rs->result_source;
1596 # we already check this, but double check naively just in case. Should be removed soon
1597 my $sel = $rs->_resolved_attrs->{select};
1598 $sel = [ $sel ] unless ref $sel eq 'ARRAY';
1599 my @pcols = $rsrc->primary_columns;
1600 if (@$sel != @pcols) {
1601 $self->throw_exception (
1602 'Subquery update/delete can not be called on resultsets selecting a'
1603 .' number of columns different than the number of primary keys'
1610 $op eq 'update' ? $values : (),
1611 { $pcols[0] => { -in => $rs->as_query } },
1616 return $self->_multipk_update_delete (@_);
1620 # ANSI SQL does not provide a reliable way to perform a multicol-PK
1621 # resultset update/delete involving subqueries. So by default resort
1622 # to simple (and inefficient) delete_all style per-row opearations,
1623 # while allowing specific storages to override this with a faster
1626 sub _multipk_update_delete {
1627 return shift->_per_row_update_delete (@_);
1630 # This is the default loop used to delete/update rows for multi PK
1631 # resultsets, and used by mysql exclusively (because it can't do anything
1634 # We do not use $row->$op style queries, because resultset update/delete
1635 # is not expected to cascade (this is what delete_all/update_all is for).
1637 # There should be no race conditions as the entire operation is rolled
1640 sub _per_row_update_delete {
1642 my ($rs, $op, $values) = @_;
1644 my $rsrc = $rs->result_source;
1645 my @pcols = $rsrc->primary_columns;
1647 my $guard = $self->txn_scope_guard;
1649 # emulate the return value of $sth->execute for non-selects
1650 my $row_cnt = '0E0';
1652 my $subrs_cur = $rs->cursor;
1653 while (my @pks = $subrs_cur->next) {
1656 for my $i (0.. $#pcols) {
1657 $cond->{$pcols[$i]} = $pks[$i];
1662 $op eq 'update' ? $values : (),
1677 # localization is neccessary as
1678 # 1) there is no infrastructure to pass this around before SQLA2
1679 # 2) _select_args sets it and _prep_for_execute consumes it
1680 my $sql_maker = $self->sql_maker;
1681 local $sql_maker->{_dbic_rs_attrs};
1683 return $self->_execute($self->_select_args(@_));
1686 sub _select_args_to_query {
1689 # localization is neccessary as
1690 # 1) there is no infrastructure to pass this around before SQLA2
1691 # 2) _select_args sets it and _prep_for_execute consumes it
1692 my $sql_maker = $self->sql_maker;
1693 local $sql_maker->{_dbic_rs_attrs};
1695 # my ($op, $bind, $ident, $bind_attrs, $select, $cond, $order, $rows, $offset)
1696 # = $self->_select_args($ident, $select, $cond, $attrs);
1697 my ($op, $bind, $ident, $bind_attrs, @args) =
1698 $self->_select_args(@_);
1700 # my ($sql, $prepared_bind) = $self->_prep_for_execute($op, $bind, $ident, [ $select, $cond, $order, $rows, $offset ]);
1701 my ($sql, $prepared_bind) = $self->_prep_for_execute($op, $bind, $ident, \@args);
1702 $prepared_bind ||= [];
1705 ? ($sql, $prepared_bind, $bind_attrs)
1706 : \[ "($sql)", @$prepared_bind ]
1711 my ($self, $ident, $select, $where, $attrs) = @_;
1713 my ($alias2source, $rs_alias) = $self->_resolve_ident_sources ($ident);
1715 my $sql_maker = $self->sql_maker;
1716 $sql_maker->{_dbic_rs_attrs} = {
1722 ? ( _source_handle => $alias2source->{$rs_alias}->handle )
1727 # calculate bind_attrs before possible $ident mangling
1728 my $bind_attrs = {};
1729 for my $alias (keys %$alias2source) {
1730 my $bindtypes = $self->source_bind_attributes ($alias2source->{$alias}) || {};
1731 for my $col (keys %$bindtypes) {
1733 my $fqcn = join ('.', $alias, $col);
1734 $bind_attrs->{$fqcn} = $bindtypes->{$col} if $bindtypes->{$col};
1736 # Unqialified column names are nice, but at the same time can be
1737 # rather ambiguous. What we do here is basically go along with
1738 # the loop, adding an unqualified column slot to $bind_attrs,
1739 # alongside the fully qualified name. As soon as we encounter
1740 # another column by that name (which would imply another table)
1741 # we unset the unqualified slot and never add any info to it
1742 # to avoid erroneous type binding. If this happens the users
1743 # only choice will be to fully qualify his column name
1745 if (exists $bind_attrs->{$col}) {
1746 $bind_attrs->{$col} = {};
1749 $bind_attrs->{$col} = $bind_attrs->{$fqcn};
1756 $attrs->{software_limit}
1758 $sql_maker->_default_limit_syntax eq "GenericSubQ"
1760 $attrs->{software_limit} = 1;
1763 $self->throw_exception("rows attribute must be positive if present")
1764 if (defined($attrs->{rows}) && !($attrs->{rows} > 0));
1766 # MySQL actually recommends this approach. I cringe.
1767 $attrs->{rows} = 2**48 if not defined $attrs->{rows} and defined $attrs->{offset};
1772 # see if we need to tear the prefetch apart (either limited has_many or grouped prefetch)
1773 # otherwise delegate the limiting to the storage, unless software limit was requested
1775 ( $attrs->{rows} && keys %{$attrs->{collapse}} )
1777 ( $attrs->{group_by} && @{$attrs->{group_by}} &&
1778 $attrs->{_prefetch_select} && @{$attrs->{_prefetch_select}} )
1780 ($ident, $select, $where, $attrs)
1781 = $self->_adjust_select_args_for_complex_prefetch ($ident, $select, $where, $attrs);
1783 elsif (! $attrs->{software_limit} ) {
1784 push @limit, $attrs->{rows}, $attrs->{offset};
1788 # This would be the point to deflate anything found in $where
1789 # (and leave $attrs->{bind} intact). Problem is - inflators historically
1790 # expect a row object. And all we have is a resultsource (it is trivial
1791 # to extract deflator coderefs via $alias2source above).
1793 # I don't see a way forward other than changing the way deflators are
1794 # invoked, and that's just bad...
1798 { $attrs->{$_} ? ( $_ => $attrs->{$_} ) : () }
1799 (qw/order_by group_by having/ )
1802 return ('select', $attrs->{bind}, $ident, $bind_attrs, $select, $where, $order, @limit);
1806 # This is the code producing joined subqueries like:
1807 # SELECT me.*, other.* FROM ( SELECT me.* FROM ... ) JOIN other ON ...
1809 sub _adjust_select_args_for_complex_prefetch {
1810 my ($self, $from, $select, $where, $attrs) = @_;
1812 $self->throw_exception ('Nothing to prefetch... how did we get here?!')
1813 if not @{$attrs->{_prefetch_select}};
1815 $self->throw_exception ('Complex prefetches are not supported on resultsets with a custom from attribute')
1816 if (ref $from ne 'ARRAY' || ref $from->[0] ne 'HASH' || ref $from->[1] ne 'ARRAY');
1819 # generate inner/outer attribute lists, remove stuff that doesn't apply
1820 my $outer_attrs = { %$attrs };
1821 delete $outer_attrs->{$_} for qw/where bind rows offset group_by having/;
1823 my $inner_attrs = { %$attrs };
1824 delete $inner_attrs->{$_} for qw/for collapse _prefetch_select _collapse_order_by select as/;
1827 # bring over all non-collapse-induced order_by into the inner query (if any)
1828 # the outer one will have to keep them all
1829 delete $inner_attrs->{order_by};
1830 if (my $ord_cnt = @{$outer_attrs->{order_by}} - @{$outer_attrs->{_collapse_order_by}} ) {
1831 $inner_attrs->{order_by} = [
1832 @{$outer_attrs->{order_by}}[ 0 .. $ord_cnt - 1]
1837 # generate the inner/outer select lists
1838 # for inside we consider only stuff *not* brought in by the prefetch
1839 # on the outside we substitute any function for its alias
1840 my $outer_select = [ @$select ];
1841 my $inner_select = [];
1842 for my $i (0 .. ( @$outer_select - @{$outer_attrs->{_prefetch_select}} - 1) ) {
1843 my $sel = $outer_select->[$i];
1845 if (ref $sel eq 'HASH' ) {
1846 $sel->{-as} ||= $attrs->{as}[$i];
1847 $outer_select->[$i] = join ('.', $attrs->{alias}, ($sel->{-as} || "inner_column_$i") );
1850 push @$inner_select, $sel;
1853 # normalize a copy of $from, so it will be easier to work with further
1854 # down (i.e. promote the initial hashref to an AoH)
1856 $from->[0] = [ $from->[0] ];
1857 my %original_join_info = map { $_->[0]{-alias} => $_->[0] } (@$from);
1860 # decide which parts of the join will remain in either part of
1861 # the outer/inner query
1863 # First we compose a list of which aliases are used in restrictions
1864 # (i.e. conditions/order/grouping/etc). Since we do not have
1865 # introspectable SQLA, we fall back to ugly scanning of raw SQL for
1866 # WHERE, and for pieces of ORDER BY in order to determine which aliases
1867 # need to appear in the resulting sql.
1868 # It may not be very efficient, but it's a reasonable stop-gap
1869 # Also unqualified column names will not be considered, but more often
1870 # than not this is actually ok
1872 # In the same loop we enumerate part of the selection aliases, as
1873 # it requires the same sqla hack for the time being
1874 my ($restrict_aliases, $select_aliases, $prefetch_aliases);
1876 # produce stuff unquoted, so it can be scanned
1877 my $sql_maker = $self->sql_maker;
1878 local $sql_maker->{quote_char};
1879 my $sep = $self->_sql_maker_opts->{name_sep} || '.';
1882 my $non_prefetch_select_sql = $sql_maker->_recurse_fields ($inner_select);
1883 my $prefetch_select_sql = $sql_maker->_recurse_fields ($outer_attrs->{_prefetch_select});
1884 my $where_sql = $sql_maker->where ($where);
1885 my $group_by_sql = $sql_maker->_order_by({
1886 map { $_ => $inner_attrs->{$_} } qw/group_by having/
1888 my @non_prefetch_order_by_chunks = (map
1889 { ref $_ ? $_->[0] : $_ }
1890 $sql_maker->_order_by_chunks ($inner_attrs->{order_by})
1894 for my $alias (keys %original_join_info) {
1895 my $seen_re = qr/\b $alias $sep/x;
1897 for my $piece ($where_sql, $group_by_sql, @non_prefetch_order_by_chunks ) {
1898 if ($piece =~ $seen_re) {
1899 $restrict_aliases->{$alias} = 1;
1903 if ($non_prefetch_select_sql =~ $seen_re) {
1904 $select_aliases->{$alias} = 1;
1907 if ($prefetch_select_sql =~ $seen_re) {
1908 $prefetch_aliases->{$alias} = 1;
1914 # Add any non-left joins to the restriction list (such joins are indeed restrictions)
1915 for my $j (values %original_join_info) {
1916 my $alias = $j->{-alias} or next;
1917 $restrict_aliases->{$alias} = 1 if (
1918 (not $j->{-join_type})
1920 ($j->{-join_type} !~ /^left (?: \s+ outer)? $/xi)
1924 # mark all join parents as mentioned
1925 # (e.g. join => { cds => 'tracks' } - tracks will need to bring cds too )
1926 for my $collection ($restrict_aliases, $select_aliases) {
1927 for my $alias (keys %$collection) {
1928 $collection->{$_} = 1
1929 for (@{ $original_join_info{$alias}{-join_path} || [] });
1933 # construct the inner $from for the subquery
1934 my %inner_joins = (map { %{$_ || {}} } ($restrict_aliases, $select_aliases) );
1936 for my $j (@$from) {
1937 push @inner_from, $j if $inner_joins{$j->[0]{-alias}};
1940 # if a multi-type join was needed in the subquery ("multi" is indicated by
1941 # presence in {collapse}) - add a group_by to simulate the collapse in the subq
1942 unless ($inner_attrs->{group_by}) {
1943 for my $alias (keys %inner_joins) {
1945 # the dot comes from some weirdness in collapse
1946 # remove after the rewrite
1947 if ($attrs->{collapse}{".$alias"}) {
1948 $inner_attrs->{group_by} ||= $inner_select;
1954 # demote the inner_from head
1955 $inner_from[0] = $inner_from[0][0];
1957 # generate the subquery
1958 my $subq = $self->_select_args_to_query (
1965 my $subq_joinspec = {
1966 -alias => $attrs->{alias},
1967 -source_handle => $inner_from[0]{-source_handle},
1968 $attrs->{alias} => $subq,
1971 # Generate the outer from - this is relatively easy (really just replace
1972 # the join slot with the subquery), with a major caveat - we can not
1973 # join anything that is non-selecting (not part of the prefetch), but at
1974 # the same time is a multi-type relationship, as it will explode the result.
1976 # There are two possibilities here
1977 # - either the join is non-restricting, in which case we simply throw it away
1978 # - it is part of the restrictions, in which case we need to collapse the outer
1979 # result by tackling yet another group_by to the outside of the query
1981 # so first generate the outer_from, up to the substitution point
1983 while (my $j = shift @$from) {
1984 if ($j->[0]{-alias} eq $attrs->{alias}) { # time to swap
1989 last; # we'll take care of what's left in $from below
1992 push @outer_from, $j;
1996 # see what's left - throw away if not selecting/restricting
1997 # also throw in a group_by if restricting to guard against
1998 # cross-join explosions
2000 while (my $j = shift @$from) {
2001 my $alias = $j->[0]{-alias};
2003 if ($select_aliases->{$alias} || $prefetch_aliases->{$alias}) {
2004 push @outer_from, $j;
2006 elsif ($restrict_aliases->{$alias}) {
2007 push @outer_from, $j;
2009 # FIXME - this should be obviated by SQLA2, as I'll be able to
2010 # have restrict_inner and restrict_outer... or something to that
2011 # effect... I think...
2013 # FIXME2 - I can't find a clean way to determine if a particular join
2014 # is a multi - instead I am just treating everything as a potential
2015 # explosive join (ribasushi)
2017 # if (my $handle = $j->[0]{-source_handle}) {
2018 # my $rsrc = $handle->resolve;
2019 # ... need to bail out of the following if this is not a multi,
2020 # as it will be much easier on the db ...
2022 $outer_attrs->{group_by} ||= $outer_select;
2027 # demote the outer_from head
2028 $outer_from[0] = $outer_from[0][0];
2030 # This is totally horrific - the $where ends up in both the inner and outer query
2031 # Unfortunately not much can be done until SQLA2 introspection arrives, and even
2032 # then if where conditions apply to the *right* side of the prefetch, you may have
2033 # to both filter the inner select (e.g. to apply a limit) and then have to re-filter
2034 # the outer select to exclude joins you didin't want in the first place
2036 # OTOH it can be seen as a plus: <ash> (notes that this query would make a DBA cry ;)
2037 return (\@outer_from, $outer_select, $where, $outer_attrs);
2040 sub _resolve_ident_sources {
2041 my ($self, $ident) = @_;
2043 my $alias2source = {};
2046 # the reason this is so contrived is that $ident may be a {from}
2047 # structure, specifying multiple tables to join
2048 if ( Scalar::Util::blessed($ident) && $ident->isa("DBIx::Class::ResultSource") ) {
2049 # this is compat mode for insert/update/delete which do not deal with aliases
2050 $alias2source->{me} = $ident;
2053 elsif (ref $ident eq 'ARRAY') {
2057 if (ref $_ eq 'HASH') {
2059 $rs_alias = $tabinfo->{-alias};
2061 if (ref $_ eq 'ARRAY' and ref $_->[0] eq 'HASH') {
2065 $alias2source->{$tabinfo->{-alias}} = $tabinfo->{-source_handle}->resolve
2066 if ($tabinfo->{-source_handle});
2070 return ($alias2source, $rs_alias);
2073 # Takes $ident, \@column_names
2075 # returns { $column_name => \%column_info, ... }
2076 # also note: this adds -result_source => $rsrc to the column info
2079 # my $col_sources = $self->_resolve_column_info($ident, @column_names);
2080 sub _resolve_column_info {
2081 my ($self, $ident, $colnames) = @_;
2082 my ($alias2src, $root_alias) = $self->_resolve_ident_sources($ident);
2084 my $sep = $self->_sql_maker_opts->{name_sep} || '.';
2087 my (%return, %seen_cols);
2089 # compile a global list of column names, to be able to properly
2090 # disambiguate unqualified column names (if at all possible)
2091 for my $alias (keys %$alias2src) {
2092 my $rsrc = $alias2src->{$alias};
2093 for my $colname ($rsrc->columns) {
2094 push @{$seen_cols{$colname}}, $alias;
2099 foreach my $col (@$colnames) {
2100 my ($alias, $colname) = $col =~ m/^ (?: ([^$sep]+) $sep)? (.+) $/x;
2103 # see if the column was seen exactly once (so we know which rsrc it came from)
2104 if ($seen_cols{$colname} and @{$seen_cols{$colname}} == 1) {
2105 $alias = $seen_cols{$colname}[0];
2112 my $rsrc = $alias2src->{$alias};
2113 $return{$col} = $rsrc && {
2114 %{$rsrc->column_info($colname)},
2115 -result_source => $rsrc,
2116 -source_alias => $alias,
2123 # Returns a counting SELECT for a simple count
2124 # query. Abstracted so that a storage could override
2125 # this to { count => 'firstcol' } or whatever makes
2126 # sense as a performance optimization
2128 #my ($self, $source, $rs_attrs) = @_;
2129 return { count => '*' };
2132 # Returns a SELECT which will end up in the subselect
2133 # There may or may not be a group_by, as the subquery
2134 # might have been called to accomodate a limit
2136 # Most databases would be happy with whatever ends up
2137 # here, but some choke in various ways.
2139 sub _subq_count_select {
2140 my ($self, $source, $rs_attrs) = @_;
2141 return $rs_attrs->{group_by} if $rs_attrs->{group_by};
2143 my @pcols = map { join '.', $rs_attrs->{alias}, $_ } ($source->primary_columns);
2144 return @pcols ? \@pcols : [ 1 ];
2147 sub source_bind_attributes {
2148 my ($self, $source) = @_;
2150 my $bind_attributes;
2151 foreach my $column ($source->columns) {
2153 my $data_type = $source->column_info($column)->{data_type} || '';
2154 $bind_attributes->{$column} = $self->bind_attribute_by_data_type($data_type)
2158 return $bind_attributes;
2165 =item Arguments: $ident, $select, $condition, $attrs
2169 Handle a SQL select statement.
2175 my ($ident, $select, $condition, $attrs) = @_;
2176 return $self->cursor_class->new($self, \@_, $attrs);
2181 my ($rv, $sth, @bind) = $self->_select(@_);
2182 my @row = $sth->fetchrow_array;
2183 my @nextrow = $sth->fetchrow_array if @row;
2184 if(@row && @nextrow) {
2185 carp "Query returned more than one row. SQL that returns multiple rows is DEPRECATED for ->find and ->single";
2187 # Need to call finish() to work round broken DBDs
2196 =item Arguments: $sql
2200 Returns a L<DBI> sth (statement handle) for the supplied SQL.
2205 my ($self, $dbh, $sql) = @_;
2207 # 3 is the if_active parameter which avoids active sth re-use
2208 my $sth = $self->disable_sth_caching
2209 ? $dbh->prepare($sql)
2210 : $dbh->prepare_cached($sql, {}, 3);
2212 # XXX You would think RaiseError would make this impossible,
2213 # but apparently that's not true :(
2214 $self->throw_exception($dbh->errstr) if !$sth;
2220 my ($self, $sql) = @_;
2221 $self->dbh_do('_dbh_sth', $sql); # retry over disconnects
2224 sub _dbh_columns_info_for {
2225 my ($self, $dbh, $table) = @_;
2227 if ($dbh->can('column_info')) {
2230 my ($schema,$tab) = $table =~ /^(.+?)\.(.+)$/ ? ($1,$2) : (undef,$table);
2231 my $sth = $dbh->column_info( undef,$schema, $tab, '%' );
2233 while ( my $info = $sth->fetchrow_hashref() ){
2235 $column_info{data_type} = $info->{TYPE_NAME};
2236 $column_info{size} = $info->{COLUMN_SIZE};
2237 $column_info{is_nullable} = $info->{NULLABLE} ? 1 : 0;
2238 $column_info{default_value} = $info->{COLUMN_DEF};
2239 my $col_name = $info->{COLUMN_NAME};
2240 $col_name =~ s/^\"(.*)\"$/$1/;
2242 $result{$col_name} = \%column_info;
2245 return \%result if !$@ && scalar keys %result;
2249 my $sth = $dbh->prepare($self->sql_maker->select($table, undef, \'1 = 0'));
2251 my @columns = @{$sth->{NAME_lc}};
2252 for my $i ( 0 .. $#columns ){
2254 $column_info{data_type} = $sth->{TYPE}->[$i];
2255 $column_info{size} = $sth->{PRECISION}->[$i];
2256 $column_info{is_nullable} = $sth->{NULLABLE}->[$i] ? 1 : 0;
2258 if ($column_info{data_type} =~ m/^(.*?)\((.*?)\)$/) {
2259 $column_info{data_type} = $1;
2260 $column_info{size} = $2;
2263 $result{$columns[$i]} = \%column_info;
2267 foreach my $col (keys %result) {
2268 my $colinfo = $result{$col};
2269 my $type_num = $colinfo->{data_type};
2271 if(defined $type_num && $dbh->can('type_info')) {
2272 my $type_info = $dbh->type_info($type_num);
2273 $type_name = $type_info->{TYPE_NAME} if $type_info;
2274 $colinfo->{data_type} = $type_name if $type_name;
2281 sub columns_info_for {
2282 my ($self, $table) = @_;
2283 $self->_dbh_columns_info_for ($self->_get_dbh, $table);
2286 =head2 last_insert_id
2288 Return the row id of the last insert.
2292 sub _dbh_last_insert_id {
2293 # All Storage's need to register their own _dbh_last_insert_id
2294 # the old SQLite-based method was highly inappropriate
2297 my $class = ref $self;
2298 $self->throw_exception (<<EOE);
2300 No _dbh_last_insert_id() method found in $class.
2301 Since the method of obtaining the autoincrement id of the last insert
2302 operation varies greatly between different databases, this method must be
2303 individually implemented for every storage class.
2307 sub last_insert_id {
2309 $self->_dbh_last_insert_id ($self->_dbh, @_);
2312 =head2 _native_data_type
2316 =item Arguments: $type_name
2320 This API is B<EXPERIMENTAL>, will almost definitely change in the future, and
2321 currently only used by L<::AutoCast|DBIx::Class::Storage::DBI::AutoCast> and
2322 L<::Sybase|DBIx::Class::Storage::DBI::Sybase>.
2324 The default implementation returns C<undef>, implement in your Storage driver if
2325 you need this functionality.
2327 Should map types from other databases to the native RDBMS type, for example
2328 C<VARCHAR2> to C<VARCHAR>.
2330 Types with modifiers should map to the underlying data type. For example,
2331 C<INTEGER AUTO_INCREMENT> should become C<INTEGER>.
2333 Composite types should map to the container type, for example
2334 C<ENUM(foo,bar,baz)> becomes C<ENUM>.
2338 sub _native_data_type {
2339 #my ($self, $data_type) = @_;
2343 # Check if placeholders are supported at all
2344 sub _placeholders_supported {
2346 my $dbh = $self->_get_dbh;
2348 # some drivers provide a $dbh attribute (e.g. Sybase and $dbh->{syb_dynamic_supported})
2349 # but it is inaccurate more often than not
2351 local $dbh->{PrintError} = 0;
2352 local $dbh->{RaiseError} = 1;
2353 $dbh->do('select ?', {}, 1);
2358 # Check if placeholders bound to non-string types throw exceptions
2360 sub _typeless_placeholders_supported {
2362 my $dbh = $self->_get_dbh;
2365 local $dbh->{PrintError} = 0;
2366 local $dbh->{RaiseError} = 1;
2367 # this specifically tests a bind that is NOT a string
2368 $dbh->do('select 1 where 1 = ?', {}, 1);
2375 Returns the database driver name.
2380 shift->_get_dbh->{Driver}->{Name};
2383 =head2 bind_attribute_by_data_type
2385 Given a datatype from column info, returns a database specific bind
2386 attribute for C<< $dbh->bind_param($val,$attribute) >> or nothing if we will
2387 let the database planner just handle it.
2389 Generally only needed for special case column types, like bytea in postgres.
2393 sub bind_attribute_by_data_type {
2397 =head2 is_datatype_numeric
2399 Given a datatype from column_info, returns a boolean value indicating if
2400 the current RDBMS considers it a numeric value. This controls how
2401 L<DBIx::Class::Row/set_column> decides whether to mark the column as
2402 dirty - when the datatype is deemed numeric a C<< != >> comparison will
2403 be performed instead of the usual C<eq>.
2407 sub is_datatype_numeric {
2408 my ($self, $dt) = @_;
2410 return 0 unless $dt;
2412 return $dt =~ /^ (?:
2413 numeric | int(?:eger)? | (?:tiny|small|medium|big)int | dec(?:imal)? | real | float | double (?: \s+ precision)? | (?:big)?serial
2418 =head2 create_ddl_dir (EXPERIMENTAL)
2422 =item Arguments: $schema \@databases, $version, $directory, $preversion, \%sqlt_args
2426 Creates a SQL file based on the Schema, for each of the specified
2427 database engines in C<\@databases> in the given directory.
2428 (note: specify L<SQL::Translator> names, not L<DBI> driver names).
2430 Given a previous version number, this will also create a file containing
2431 the ALTER TABLE statements to transform the previous schema into the
2432 current one. Note that these statements may contain C<DROP TABLE> or
2433 C<DROP COLUMN> statements that can potentially destroy data.
2435 The file names are created using the C<ddl_filename> method below, please
2436 override this method in your schema if you would like a different file
2437 name format. For the ALTER file, the same format is used, replacing
2438 $version in the name with "$preversion-$version".
2440 See L<SQL::Translator/METHODS> for a list of values for C<\%sqlt_args>.
2441 The most common value for this would be C<< { add_drop_table => 1 } >>
2442 to have the SQL produced include a C<DROP TABLE> statement for each table
2443 created. For quoting purposes supply C<quote_table_names> and
2444 C<quote_field_names>.
2446 If no arguments are passed, then the following default values are assumed:
2450 =item databases - ['MySQL', 'SQLite', 'PostgreSQL']
2452 =item version - $schema->schema_version
2454 =item directory - './'
2456 =item preversion - <none>
2460 By default, C<\%sqlt_args> will have
2462 { add_drop_table => 1, ignore_constraint_names => 1, ignore_index_names => 1 }
2464 merged with the hash passed in. To disable any of those features, pass in a
2465 hashref like the following
2467 { ignore_constraint_names => 0, # ... other options }
2470 Note that this feature is currently EXPERIMENTAL and may not work correctly
2471 across all databases, or fully handle complex relationships.
2473 WARNING: Please check all SQL files created, before applying them.
2477 sub create_ddl_dir {
2478 my ($self, $schema, $databases, $version, $dir, $preversion, $sqltargs) = @_;
2480 if(!$dir || !-d $dir) {
2481 carp "No directory given, using ./\n";
2484 $databases ||= ['MySQL', 'SQLite', 'PostgreSQL'];
2485 $databases = [ $databases ] if(ref($databases) ne 'ARRAY');
2487 my $schema_version = $schema->schema_version || '1.x';
2488 $version ||= $schema_version;
2491 add_drop_table => 1,
2492 ignore_constraint_names => 1,
2493 ignore_index_names => 1,
2497 $self->throw_exception("Can't create a ddl file without SQL::Translator: " . $self->_sqlt_version_error)
2498 if !$self->_sqlt_version_ok;
2500 my $sqlt = SQL::Translator->new( $sqltargs );
2502 $sqlt->parser('SQL::Translator::Parser::DBIx::Class');
2503 my $sqlt_schema = $sqlt->translate({ data => $schema })
2504 or $self->throw_exception ($sqlt->error);
2506 foreach my $db (@$databases) {
2508 $sqlt->{schema} = $sqlt_schema;
2509 $sqlt->producer($db);
2512 my $filename = $schema->ddl_filename($db, $version, $dir);
2513 if (-e $filename && ($version eq $schema_version )) {
2514 # if we are dumping the current version, overwrite the DDL
2515 carp "Overwriting existing DDL file - $filename";
2519 my $output = $sqlt->translate;
2521 carp("Failed to translate to $db, skipping. (" . $sqlt->error . ")");
2524 if(!open($file, ">$filename")) {
2525 $self->throw_exception("Can't open $filename for writing ($!)");
2528 print $file $output;
2531 next unless ($preversion);
2533 require SQL::Translator::Diff;
2535 my $prefilename = $schema->ddl_filename($db, $preversion, $dir);
2536 if(!-e $prefilename) {
2537 carp("No previous schema file found ($prefilename)");
2541 my $difffile = $schema->ddl_filename($db, $version, $dir, $preversion);
2543 carp("Overwriting existing diff file - $difffile");
2549 my $t = SQL::Translator->new($sqltargs);
2554 or $self->throw_exception ($t->error);
2556 my $out = $t->translate( $prefilename )
2557 or $self->throw_exception ($t->error);
2559 $source_schema = $t->schema;
2561 $source_schema->name( $prefilename )
2562 unless ( $source_schema->name );
2565 # The "new" style of producers have sane normalization and can support
2566 # diffing a SQL file against a DBIC->SQLT schema. Old style ones don't
2567 # And we have to diff parsed SQL against parsed SQL.
2568 my $dest_schema = $sqlt_schema;
2570 unless ( "SQL::Translator::Producer::$db"->can('preprocess_schema') ) {
2571 my $t = SQL::Translator->new($sqltargs);
2576 or $self->throw_exception ($t->error);
2578 my $out = $t->translate( $filename )
2579 or $self->throw_exception ($t->error);
2581 $dest_schema = $t->schema;
2583 $dest_schema->name( $filename )
2584 unless $dest_schema->name;
2587 my $diff = SQL::Translator::Diff::schema_diff($source_schema, $db,
2591 if(!open $file, ">$difffile") {
2592 $self->throw_exception("Can't write to $difffile ($!)");
2600 =head2 deployment_statements
2604 =item Arguments: $schema, $type, $version, $directory, $sqlt_args
2608 Returns the statements used by L</deploy> and L<DBIx::Class::Schema/deploy>.
2610 The L<SQL::Translator> (not L<DBI>) database driver name can be explicitly
2611 provided in C<$type>, otherwise the result of L</sqlt_type> is used as default.
2613 C<$directory> is used to return statements from files in a previously created
2614 L</create_ddl_dir> directory and is optional. The filenames are constructed
2615 from L<DBIx::Class::Schema/ddl_filename>, the schema name and the C<$version>.
2617 If no C<$directory> is specified then the statements are constructed on the
2618 fly using L<SQL::Translator> and C<$version> is ignored.
2620 See L<SQL::Translator/METHODS> for a list of values for C<$sqlt_args>.
2624 sub deployment_statements {
2625 my ($self, $schema, $type, $version, $dir, $sqltargs) = @_;
2626 $type ||= $self->sqlt_type;
2627 $version ||= $schema->schema_version || '1.x';
2629 my $filename = $schema->ddl_filename($type, $version, $dir);
2633 open($file, "<$filename")
2634 or $self->throw_exception("Can't open $filename ($!)");
2637 return join('', @rows);
2640 $self->throw_exception("Can't deploy without either SQL::Translator or a ddl_dir: " . $self->_sqlt_version_error )
2641 if !$self->_sqlt_version_ok;
2643 # sources needs to be a parser arg, but for simplicty allow at top level
2645 $sqltargs->{parser_args}{sources} = delete $sqltargs->{sources}
2646 if exists $sqltargs->{sources};
2648 my $tr = SQL::Translator->new(
2649 producer => "SQL::Translator::Producer::${type}",
2651 parser => 'SQL::Translator::Parser::DBIx::Class',
2655 my $ret = $tr->translate
2656 or $self->throw_exception( 'Unable to produce deployment statements: ' . $tr->error);
2662 my ($self, $schema, $type, $sqltargs, $dir) = @_;
2665 return if($line =~ /^--/);
2667 # next if($line =~ /^DROP/m);
2668 return if($line =~ /^BEGIN TRANSACTION/m);
2669 return if($line =~ /^COMMIT/m);
2670 return if $line =~ /^\s+$/; # skip whitespace only
2671 $self->_query_start($line);
2673 # do a dbh_do cycle here, as we need some error checking in
2674 # place (even though we will ignore errors)
2675 $self->dbh_do (sub { $_[1]->do($line) });
2678 carp qq{$@ (running "${line}")};
2680 $self->_query_end($line);
2682 my @statements = $self->deployment_statements($schema, $type, undef, $dir, { %{ $sqltargs || {} }, no_comments => 1 } );
2683 if (@statements > 1) {
2684 foreach my $statement (@statements) {
2685 $deploy->( $statement );
2688 elsif (@statements == 1) {
2689 foreach my $line ( split(";\n", $statements[0])) {
2695 =head2 datetime_parser
2697 Returns the datetime parser class
2701 sub datetime_parser {
2703 return $self->{datetime_parser} ||= do {
2704 $self->build_datetime_parser(@_);
2708 =head2 datetime_parser_type
2710 Defines (returns) the datetime parser class - currently hardwired to
2711 L<DateTime::Format::MySQL>
2715 sub datetime_parser_type { "DateTime::Format::MySQL"; }
2717 =head2 build_datetime_parser
2719 See L</datetime_parser>
2723 sub build_datetime_parser {
2725 my $type = $self->datetime_parser_type(@_);
2726 $self->ensure_class_loaded ($type);
2731 =head2 is_replicating
2733 A boolean that reports if a particular L<DBIx::Class::Storage::DBI> is set to
2734 replicate from a master database. Default is undef, which is the result
2735 returned by databases that don't support replication.
2739 sub is_replicating {
2744 =head2 lag_behind_master
2746 Returns a number that represents a certain amount of lag behind a master db
2747 when a given storage is replicating. The number is database dependent, but
2748 starts at zero and increases with the amount of lag. Default in undef
2752 sub lag_behind_master {
2756 # SQLT version handling
2758 my $_sqlt_version_ok; # private
2759 my $_sqlt_version_error; # private
2761 sub _sqlt_version_ok {
2762 if (!defined $_sqlt_version_ok) {
2763 eval "use SQL::Translator $minimum_sqlt_version";
2765 $_sqlt_version_ok = 0;
2766 $_sqlt_version_error = $@;
2769 $_sqlt_version_ok = 1;
2772 return $_sqlt_version_ok;
2775 sub _sqlt_version_error {
2776 shift->_sqlt_version_ok unless defined $_sqlt_version_ok;
2777 return $_sqlt_version_error;
2780 sub _sqlt_minimum_version { $minimum_sqlt_version };
2786 $self->_verify_pid if $self->_dbh;
2788 # some databases need this to stop spewing warnings
2789 if (my $dbh = $self->_dbh) {
2791 eval { $dbh->disconnect };
2801 =head2 DBIx::Class and AutoCommit
2803 DBIx::Class can do some wonderful magic with handling exceptions,
2804 disconnections, and transactions when you use C<< AutoCommit => 1 >>
2805 (the default) combined with C<txn_do> for transaction support.
2807 If you set C<< AutoCommit => 0 >> in your connect info, then you are always
2808 in an assumed transaction between commits, and you're telling us you'd
2809 like to manage that manually. A lot of the magic protections offered by
2810 this module will go away. We can't protect you from exceptions due to database
2811 disconnects because we don't know anything about how to restart your
2812 transactions. You're on your own for handling all sorts of exceptional
2813 cases if you choose the C<< AutoCommit => 0 >> path, just as you would
2819 Matt S. Trout <mst@shadowcatsystems.co.uk>
2821 Andy Grundman <andy@hybridized.org>
2825 You may distribute this code under the same terms as Perl itself.