use strict;
use warnings;
-use base qw/DBIx::Class::Storage::DBI::AmbiguousGlob DBIx::Class::Storage::DBI/;
+use base qw/DBIx::Class::Storage::DBI::UniqueIdentifier/;
use mro 'c3';
use List::Util();
}
}
-# support MSSQL GUID column types
-
sub insert {
my $self = shift;
my ($source, $to_insert) = @_;
my $supplied_col_info = $self->_resolve_column_info($source, [keys %$to_insert] );
- my %guid_cols;
- my @pk_cols = $source->primary_columns;
- my %pk_cols;
- @pk_cols{@pk_cols} = ();
-
- my @pk_guids = grep {
- $source->column_info($_)->{data_type}
- &&
- $source->column_info($_)->{data_type} =~ /^uniqueidentifier/i
- } @pk_cols;
-
- my @auto_guids = grep {
- $source->column_info($_)->{data_type}
- &&
- $source->column_info($_)->{data_type} =~ /^uniqueidentifier/i
- &&
- $source->column_info($_)->{auto_nextval}
- } grep { not exists $pk_cols{$_} } $source->columns;
-
- my @get_guids_for =
- grep { not exists $to_insert->{$_} } (@pk_guids, @auto_guids);
-
- my $updated_cols = {};
-
- for my $guid_col (@get_guids_for) {
- my ($new_guid) = $self->_get_dbh->selectrow_array('SELECT NEWID()');
- $updated_cols->{$guid_col} = $to_insert->{$guid_col} = $new_guid;
- }
-
my $is_identity_insert = (List::Util::first { $_->{is_auto_increment} } (values %$supplied_col_info) )
? 1
: 0;
$self->_set_identity_insert ($source->name);
}
- $updated_cols = { %$updated_cols, %{ $self->next::method(@_) } };
+ my $updated_cols = $self->next::method(@_);
if ($is_identity_insert) {
$self->_unset_identity_insert ($source->name);
}
-
return $updated_cols;
}
sub last_insert_id { shift->_identity }
#
-# MSSQL is retarded wrt ordered subselects. One needs to add a TOP 100%
-# to *all* subqueries, do it here.
+# MSSQL is retarded wrt ordered subselects. One needs to add a TOP
+# to *all* subqueries, but one also can't use TOP 100 PERCENT
+# http://sqladvice.com/forums/permalink/18496/22931/ShowThread.aspx#22931
#
sub _select_args_to_query {
my $self = shift;
# see if this is an ordered subquery
my $attrs = $_[3];
- if ( scalar $self->sql_maker->_order_by_chunks ($attrs->{order_by}) ) {
- $sql =~ s/^ \s* SELECT \s/SELECT TOP 100 PERCENT /xi;
+ if (
+ $sql !~ /^ \s* SELECT \s+ TOP \s+ \d+ \s+ /xi
+ &&
+ scalar $self->_parse_order_by ($attrs->{order_by})
+ ) {
+ $self->throw_exception(
+ 'An ordered subselect encountered - this is not safe! Please see "Ordered Subselects" in DBIx::Class::Storage::DBI::MSSQL
+ ') unless $attrs->{unsafe_subselect_ok};
+ my $max = 2 ** 32;
+ $sql =~ s/^ \s* SELECT \s/SELECT TOP $max /xi;
}
return wantarray
$self->_get_dbh->do("ROLLBACK TRANSACTION $name");
}
-sub build_datetime_parser {
- my $self = shift;
- my $type = "DateTime::Format::Strptime";
- eval "use ${type}";
- $self->throw_exception("Couldn't load ${type}: $@") if $@;
- return $type->new( pattern => '%Y-%m-%d %H:%M:%S' ); # %F %T
-}
+sub datetime_parser_type {
+ 'DBIx::Class::Storage::DBI::MSSQL::DateTime::Format'
+}
sub sqlt_type { 'SQLServer' }
-sub _sql_maker_opts {
- my ( $self, $opts ) = @_;
+sub sql_maker {
+ my $self = shift;
+
+ unless ($self->_sql_maker) {
+ unless ($self->{_sql_maker_opts}{limit_dialect}) {
+ my $have_rno = 0;
+
+ if (exists $self->_server_info->{normalized_dbms_version}) {
+ $have_rno = 1 if $self->_server_info->{normalized_dbms_version} >= 9;
+ }
+ else {
+ # User is connecting via DBD::Sybase and has no permission to run
+ # stored procedures like xp_msver, or version detection failed for some
+ # other reason.
+ # So, we use a query to check if RNO is implemented.
+ $have_rno = 1 if (eval { local $@; ($self->_get_dbh
+ ->selectrow_array('SELECT row_number() OVER (ORDER BY rand())')
+ )[0] });
+ }
- if ( $opts ) {
- $self->{_sql_maker_opts} = { %$opts };
+ $self->{_sql_maker_opts} = {
+ limit_dialect => ($have_rno ? 'RowNumberOver' : 'Top'),
+ %{$self->{_sql_maker_opts}||{}}
+ };
+ }
+
+ my $maker = $self->next::method (@_);
}
- return { limit_dialect => 'RowNumberOver', %{$self->{_sql_maker_opts}||{}} };
+ return $self->_sql_maker;
+}
+
+sub _ping {
+ my $self = shift;
+
+ my $dbh = $self->_dbh or return 0;
+
+ local $dbh->{RaiseError} = 1;
+ local $dbh->{PrintError} = 0;
+
+ eval {
+ $dbh->do('select 1');
+ };
+
+ return $@ ? 0 : 1;
+}
+
+package # hide from PAUSE
+ DBIx::Class::Storage::DBI::MSSQL::DateTime::Format;
+
+my $datetime_format = '%Y-%m-%d %H:%M:%S.%3N'; # %F %T
+my $smalldatetime_format = '%Y-%m-%d %H:%M:%S';
+
+my ($datetime_parser, $smalldatetime_parser);
+
+sub parse_datetime {
+ shift;
+ require DateTime::Format::Strptime;
+ $datetime_parser ||= DateTime::Format::Strptime->new(
+ pattern => $datetime_format,
+ on_error => 'croak',
+ );
+ return $datetime_parser->parse_datetime(shift);
+}
+
+sub format_datetime {
+ shift;
+ require DateTime::Format::Strptime;
+ $datetime_parser ||= DateTime::Format::Strptime->new(
+ pattern => $datetime_format,
+ on_error => 'croak',
+ );
+ return $datetime_parser->format_datetime(shift);
+}
+
+sub parse_smalldatetime {
+ shift;
+ require DateTime::Format::Strptime;
+ $smalldatetime_parser ||= DateTime::Format::Strptime->new(
+ pattern => $smalldatetime_format,
+ on_error => 'croak',
+ );
+ return $smalldatetime_parser->parse_datetime(shift);
+}
+
+sub format_smalldatetime {
+ shift;
+ require DateTime::Format::Strptime;
+ $smalldatetime_parser ||= DateTime::Format::Strptime->new(
+ pattern => $smalldatetime_format,
+ on_error => 'croak',
+ );
+ return $smalldatetime_parser->format_datetime(shift);
}
1;
C<db_ddladmin> privilege, which is normally not included in the standard
write-permissions.
+=head2 Ordered Subselects
+
+If you attempted the following query (among many others) in Microsoft SQL
+Server
+
+ $rs->search ({}, {
+ prefetch => 'relation',
+ rows => 2,
+ offset => 3,
+ });
+
+You may be surprised to receive an exception. The reason for this is a quirk
+in the MSSQL engine itself, and sadly doesn't have a sensible workaround due
+to the way DBIC is built. DBIC can do truly wonderful things with the aid of
+subselects, and does so automatically when necessary. The list of situations
+when a subselect is necessary is long and still changes often, so it can not
+be exhaustively enumerated here. The general rule of thumb is a joined
+L<has_many|DBIx::Class::Relationship/has_many> relationship with limit/group
+applied to the left part of the join.
+
+In its "pursuit of standards" Microsft SQL Server goes to great lengths to
+forbid the use of ordered subselects. This breaks a very useful group of
+searches like "Give me things number 4 to 6 (ordered by name), and prefetch
+all their relations, no matter how many". While there is a hack which fools
+the syntax checker, the optimizer may B<still elect to break the subselect>.
+Testing has determined that while such breakage does occur (the test suite
+contains an explicit test which demonstrates the problem), it is relative
+rare. The benefits of ordered subselects are on the other hand too great to be
+outright disabled for MSSQL.
+
+Thus compromise between usability and perfection is the MSSQL-specific
+L<resultset attribute|DBIx::Class::ResultSet/ATTRIBUTES> C<unsafe_subselect_ok>.
+It is deliberately not possible to set this on the Storage level, as the user
+should inspect (and preferably regression-test) the return of every such
+ResultSet individually. The example above would work if written like:
+
+ $rs->search ({}, {
+ unsafe_subselect_ok => 1,
+ prefetch => 'relation',
+ rows => 2,
+ offset => 3,
+ });
+
+If it is possible to rewrite the search() in a way that will avoid the need
+for this flag - you are urged to do so. If DBIC internals insist that an
+ordered subselect is necessary for an operation, and you believe there is a
+different/better way to get the same result - please file a bugreport.
+
=head1 AUTHOR
-See L<DBIx::Class/CONTRIBUTORS>.
+See L<DBIx::Class/AUTHOR> and L<DBIx::Class/CONTRIBUTORS>.
=head1 LICENSE