1 package DBIx::Class::Storage::DBI::MSSQL;
6 use base qw/DBIx::Class::Storage::DBI::UniqueIdentifier/;
11 __PACKAGE__->mk_group_accessors(simple => qw/
12 _identity _identity_method
15 __PACKAGE__->sql_maker_class('DBIx::Class::SQLAHacks::MSSQL');
17 sub _set_identity_insert {
18 my ($self, $table) = @_;
21 'SET IDENTITY_INSERT %s ON',
22 $self->sql_maker->_quote ($table),
25 my $dbh = $self->_get_dbh;
26 eval { $dbh->do ($sql) };
28 $self->throw_exception (sprintf "Error executing '%s': %s",
35 sub _unset_identity_insert {
36 my ($self, $table) = @_;
39 'SET IDENTITY_INSERT %s OFF',
40 $self->sql_maker->_quote ($table),
43 my $dbh = $self->_get_dbh;
49 my ($source, $cols, $data) = @_;
51 my $is_identity_insert = (List::Util::first
52 { $source->column_info ($_)->{is_auto_increment} }
58 if ($is_identity_insert) {
59 $self->_set_identity_insert ($source->name);
62 $self->next::method(@_);
64 if ($is_identity_insert) {
65 $self->_unset_identity_insert ($source->name);
71 my ($source, $to_insert) = @_;
73 my $supplied_col_info = $self->_resolve_column_info($source, [keys %$to_insert] );
75 my $is_identity_insert = (List::Util::first { $_->{is_auto_increment} } (values %$supplied_col_info) )
79 if ($is_identity_insert) {
80 $self->_set_identity_insert ($source->name);
83 my $updated_cols = $self->next::method(@_);
85 if ($is_identity_insert) {
86 $self->_unset_identity_insert ($source->name);
92 sub _prep_for_execute {
94 my ($op, $extra_bind, $ident, $args) = @_;
96 # cast MONEY values properly
97 if ($op eq 'insert' || $op eq 'update') {
98 my $fields = $args->[0];
100 for my $col (keys %$fields) {
101 # $ident is a result source object with INSERT/UPDATE ops
102 if ($ident->column_info ($col)->{data_type}
104 $ident->column_info ($col)->{data_type} =~ /^money\z/i) {
105 my $val = $fields->{$col};
106 $fields->{$col} = \['CAST(? AS MONEY)', [ $col => $val ]];
111 my ($sql, $bind) = $self->next::method (@_);
113 if ($op eq 'insert') {
114 $sql .= ';SELECT SCOPE_IDENTITY()';
118 return ($sql, $bind);
125 my ($rv, $sth, @bind) = $self->dbh_do($self->can('_dbh_execute'), @_);
127 if ($op eq 'insert') {
129 # this should bring back the result of SELECT SCOPE_IDENTITY() we tacked
130 # on in _prep_for_execute above
131 my ($identity) = eval { $sth->fetchrow_array };
133 # SCOPE_IDENTITY failed, but we can do something else
134 if ( (! $identity) && $self->_identity_method) {
135 ($identity) = $self->_dbh->selectrow_array(
136 'select ' . $self->_identity_method
140 $self->_identity($identity);
144 return wantarray ? ($rv, $sth, @bind) : $rv;
147 sub last_insert_id { shift->_identity }
150 # MSSQL is retarded wrt ordered subselects. One needs to add a TOP
151 # to *all* subqueries, but one also can't use TOP 100 PERCENT
152 # http://sqladvice.com/forums/permalink/18496/22931/ShowThread.aspx#22931
154 sub _select_args_to_query {
157 my ($sql, $prep_bind, @rest) = $self->next::method (@_);
159 # see if this is an ordered subquery
162 $sql !~ /^ \s* SELECT \s+ TOP \s+ \d+ \s+ /xi
164 scalar $self->_parse_order_by ($attrs->{order_by})
166 $self->throw_exception(
167 'An ordered subselect encountered - this is not safe! Please see "Ordered Subselects" in DBIx::Class::Storage::DBI::MSSQL
168 ') unless $attrs->{unsafe_subselect_ok};
170 $sql =~ s/^ \s* SELECT \s/SELECT TOP $max /xi;
174 ? ($sql, $prep_bind, @rest)
175 : \[ "($sql)", @$prep_bind ]
180 # savepoint syntax is the same as in Sybase ASE
183 my ($self, $name) = @_;
185 $self->_get_dbh->do("SAVE TRANSACTION $name");
188 # A new SAVE TRANSACTION with the same name releases the previous one.
189 sub _svp_release { 1 }
192 my ($self, $name) = @_;
194 $self->_get_dbh->do("ROLLBACK TRANSACTION $name");
197 sub datetime_parser_type {
198 'DBIx::Class::Storage::DBI::MSSQL::DateTime::Format'
201 sub sqlt_type { 'SQLServer' }
206 unless ($self->_sql_maker) {
207 unless ($self->{_sql_maker_opts}{limit_dialect}) {
209 my $version = $self->_server_info->{normalized_dbms_version} || 0;
211 $self->{_sql_maker_opts} = {
212 limit_dialect => ($version >= 9 ? 'RowNumberOver' : 'Top'),
213 %{$self->{_sql_maker_opts}||{}}
217 my $maker = $self->next::method (@_);
220 return $self->_sql_maker;
226 my $dbh = $self->_dbh or return 0;
228 local $dbh->{RaiseError} = 1;
229 local $dbh->{PrintError} = 0;
232 $dbh->do('select 1');
238 package # hide from PAUSE
239 DBIx::Class::Storage::DBI::MSSQL::DateTime::Format;
241 my $datetime_format = '%Y-%m-%d %H:%M:%S.%3N'; # %F %T
242 my $smalldatetime_format = '%Y-%m-%d %H:%M:%S';
244 my ($datetime_parser, $smalldatetime_parser);
248 require DateTime::Format::Strptime;
249 $datetime_parser ||= DateTime::Format::Strptime->new(
250 pattern => $datetime_format,
253 return $datetime_parser->parse_datetime(shift);
256 sub format_datetime {
258 require DateTime::Format::Strptime;
259 $datetime_parser ||= DateTime::Format::Strptime->new(
260 pattern => $datetime_format,
263 return $datetime_parser->format_datetime(shift);
266 sub parse_smalldatetime {
268 require DateTime::Format::Strptime;
269 $smalldatetime_parser ||= DateTime::Format::Strptime->new(
270 pattern => $smalldatetime_format,
273 return $smalldatetime_parser->parse_datetime(shift);
276 sub format_smalldatetime {
278 require DateTime::Format::Strptime;
279 $smalldatetime_parser ||= DateTime::Format::Strptime->new(
280 pattern => $smalldatetime_format,
283 return $smalldatetime_parser->format_datetime(shift);
290 DBIx::Class::Storage::DBI::MSSQL - Base Class for Microsoft SQL Server support
295 This is the base class for Microsoft SQL Server support, used by
296 L<DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server> and
297 L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>.
299 =head1 IMPLEMENTATION NOTES
301 =head2 IDENTITY information
303 Microsoft SQL Server supports three methods of retrieving the IDENTITY
304 value for inserted row: IDENT_CURRENT, @@IDENTITY, and SCOPE_IDENTITY().
305 SCOPE_IDENTITY is used here because it is the safest. However, it must
306 be called is the same execute statement, not just the same connection.
308 So, this implementation appends a SELECT SCOPE_IDENTITY() statement
309 onto each INSERT to accommodate that requirement.
311 C<SELECT @@IDENTITY> can also be used by issuing:
313 $self->_identity_method('@@identity');
315 it will only be used if SCOPE_IDENTITY() fails.
317 This is more dangerous, as inserting into a table with an on insert trigger that
318 inserts into another table with an identity will give erroneous results on
319 recent versions of SQL Server.
321 =head2 identity insert
323 Be aware that we have tried to make things as simple as possible for our users.
324 For MSSQL that means that when a user tries to create a row, while supplying an
325 explicit value for an autoincrementing column, we will try to issue the
326 appropriate database call to make this possible, namely C<SET IDENTITY_INSERT
327 $table_name ON>. Unfortunately this operation in MSSQL requires the
328 C<db_ddladmin> privilege, which is normally not included in the standard
331 =head2 Ordered Subselects
333 If you attempted the following query (among many others) in Microsoft SQL
337 prefetch => 'relation',
342 You may be surprised to receive an exception. The reason for this is a quirk
343 in the MSSQL engine itself, and sadly doesn't have a sensible workaround due
344 to the way DBIC is built. DBIC can do truly wonderful things with the aid of
345 subselects, and does so automatically when necessary. The list of situations
346 when a subselect is necessary is long and still changes often, so it can not
347 be exhaustively enumerated here. The general rule of thumb is a joined
348 L<has_many|DBIx::Class::Relationship/has_many> relationship with limit/group
349 applied to the left part of the join.
351 In its "pursuit of standards" Microsft SQL Server goes to great lengths to
352 forbid the use of ordered subselects. This breaks a very useful group of
353 searches like "Give me things number 4 to 6 (ordered by name), and prefetch
354 all their relations, no matter how many". While there is a hack which fools
355 the syntax checker, the optimizer may B<still elect to break the subselect>.
356 Testing has determined that while such breakage does occur (the test suite
357 contains an explicit test which demonstrates the problem), it is relative
358 rare. The benefits of ordered subselects are on the other hand too great to be
359 outright disabled for MSSQL.
361 Thus compromise between usability and perfection is the MSSQL-specific
362 L<resultset attribute|DBIx::Class::ResultSet/ATTRIBUTES> C<unsafe_subselect_ok>.
363 It is deliberately not possible to set this on the Storage level, as the user
364 should inspect (and preferably regression-test) the return of every such
365 ResultSet individually. The example above would work if written like:
368 unsafe_subselect_ok => 1,
369 prefetch => 'relation',
374 If it is possible to rewrite the search() in a way that will avoid the need
375 for this flag - you are urged to do so. If DBIC internals insist that an
376 ordered subselect is necessary for an operation, and you believe there is a
377 different/better way to get the same result - please file a bugreport.
381 See L<DBIx::Class/AUTHOR> and L<DBIx::Class/CONTRIBUTORS>.
385 You may distribute this code under the same terms as Perl itself.