1 package DBIx::Class::Storage::DBI::MSSQL;
6 use base qw/DBIx::Class::Storage::DBI::UniqueIdentifier/;
12 __PACKAGE__->mk_group_accessors(simple => qw/
13 _identity _identity_method
16 __PACKAGE__->sql_maker_class('DBIx::Class::SQLAHacks::MSSQL');
18 sub _set_identity_insert {
19 my ($self, $table) = @_;
22 'SET IDENTITY_INSERT %s ON',
23 $self->sql_maker->_quote ($table),
26 my $dbh = $self->_get_dbh;
27 try { $dbh->do ($sql) }
29 $self->throw_exception (sprintf "Error executing '%s': %s",
36 sub _unset_identity_insert {
37 my ($self, $table) = @_;
40 'SET IDENTITY_INSERT %s OFF',
41 $self->sql_maker->_quote ($table),
44 my $dbh = $self->_get_dbh;
50 my ($source, $cols, $data) = @_;
52 my $is_identity_insert = (List::Util::first
53 { $source->column_info ($_)->{is_auto_increment} }
59 if ($is_identity_insert) {
60 $self->_set_identity_insert ($source->name);
63 $self->next::method(@_);
65 if ($is_identity_insert) {
66 $self->_unset_identity_insert ($source->name);
72 my ($source, $to_insert) = @_;
74 my $supplied_col_info = $self->_resolve_column_info($source, [keys %$to_insert] );
76 my $is_identity_insert = (List::Util::first { $_->{is_auto_increment} } (values %$supplied_col_info) )
80 if ($is_identity_insert) {
81 $self->_set_identity_insert ($source->name);
84 my $updated_cols = $self->next::method(@_);
86 if ($is_identity_insert) {
87 $self->_unset_identity_insert ($source->name);
93 sub _prep_for_execute {
95 my ($op, $extra_bind, $ident, $args) = @_;
97 # cast MONEY values properly
98 if ($op eq 'insert' || $op eq 'update') {
99 my $fields = $args->[0];
101 for my $col (keys %$fields) {
102 # $ident is a result source object with INSERT/UPDATE ops
103 if ($ident->column_info ($col)->{data_type}
105 $ident->column_info ($col)->{data_type} =~ /^money\z/i) {
106 my $val = $fields->{$col};
107 $fields->{$col} = \['CAST(? AS MONEY)', [ $col => $val ]];
112 my ($sql, $bind) = $self->next::method (@_);
114 if ($op eq 'insert') {
115 $sql .= ';SELECT SCOPE_IDENTITY()';
119 return ($sql, $bind);
126 my ($rv, $sth, @bind) = $self->dbh_do($self->can('_dbh_execute'), @_);
128 if ($op eq 'insert') {
130 # this should bring back the result of SELECT SCOPE_IDENTITY() we tacked
131 # on in _prep_for_execute above
132 my ($identity) = try { $sth->fetchrow_array };
134 # SCOPE_IDENTITY failed, but we can do something else
135 if ( (! $identity) && $self->_identity_method) {
136 ($identity) = $self->_dbh->selectrow_array(
137 'select ' . $self->_identity_method
141 $self->_identity($identity);
145 return wantarray ? ($rv, $sth, @bind) : $rv;
148 sub last_insert_id { shift->_identity }
151 # MSSQL is retarded wrt ordered subselects. One needs to add a TOP
152 # to *all* subqueries, but one also can't use TOP 100 PERCENT
153 # http://sqladvice.com/forums/permalink/18496/22931/ShowThread.aspx#22931
155 sub _select_args_to_query {
158 my ($sql, $prep_bind, @rest) = $self->next::method (@_);
160 # see if this is an ordered subquery
163 $sql !~ /^ \s* SELECT \s+ TOP \s+ \d+ \s+ /xi
165 scalar $self->_parse_order_by ($attrs->{order_by})
167 $self->throw_exception(
168 'An ordered subselect encountered - this is not safe! Please see "Ordered Subselects" in DBIx::Class::Storage::DBI::MSSQL
169 ') unless $attrs->{unsafe_subselect_ok};
171 $sql =~ s/^ \s* SELECT \s/SELECT TOP $max /xi;
175 ? ($sql, $prep_bind, @rest)
176 : \[ "($sql)", @$prep_bind ]
181 # savepoint syntax is the same as in Sybase ASE
184 my ($self, $name) = @_;
186 $self->_get_dbh->do("SAVE TRANSACTION $name");
189 # A new SAVE TRANSACTION with the same name releases the previous one.
190 sub _svp_release { 1 }
193 my ($self, $name) = @_;
195 $self->_get_dbh->do("ROLLBACK TRANSACTION $name");
198 sub datetime_parser_type {
199 'DBIx::Class::Storage::DBI::MSSQL::DateTime::Format'
202 sub sqlt_type { 'SQLServer' }
207 unless ($self->_sql_maker) {
208 unless ($self->{_sql_maker_opts}{limit_dialect}) {
211 if (exists $self->_server_info->{normalized_dbms_version}) {
212 $have_rno = 1 if $self->_server_info->{normalized_dbms_version} >= 9;
215 # User is connecting via DBD::Sybase and has no permission to run
216 # stored procedures like xp_msver, or version detection failed for some
218 # So, we use a query to check if RNO is implemented.
220 $self->_get_dbh->selectrow_array('SELECT row_number() OVER (ORDER BY rand())');
225 $self->{_sql_maker_opts} = {
226 limit_dialect => ($have_rno ? 'RowNumberOver' : 'Top'),
227 %{$self->{_sql_maker_opts}||{}}
231 my $maker = $self->next::method (@_);
234 return $self->_sql_maker;
240 my $dbh = $self->_dbh or return 0;
242 local $dbh->{RaiseError} = 1;
243 local $dbh->{PrintError} = 0;
246 $dbh->do('select 1');
253 package # hide from PAUSE
254 DBIx::Class::Storage::DBI::MSSQL::DateTime::Format;
256 my $datetime_format = '%Y-%m-%d %H:%M:%S.%3N'; # %F %T
257 my $smalldatetime_format = '%Y-%m-%d %H:%M:%S';
259 my ($datetime_parser, $smalldatetime_parser);
263 require DateTime::Format::Strptime;
264 $datetime_parser ||= DateTime::Format::Strptime->new(
265 pattern => $datetime_format,
268 return $datetime_parser->parse_datetime(shift);
271 sub format_datetime {
273 require DateTime::Format::Strptime;
274 $datetime_parser ||= DateTime::Format::Strptime->new(
275 pattern => $datetime_format,
278 return $datetime_parser->format_datetime(shift);
281 sub parse_smalldatetime {
283 require DateTime::Format::Strptime;
284 $smalldatetime_parser ||= DateTime::Format::Strptime->new(
285 pattern => $smalldatetime_format,
288 return $smalldatetime_parser->parse_datetime(shift);
291 sub format_smalldatetime {
293 require DateTime::Format::Strptime;
294 $smalldatetime_parser ||= DateTime::Format::Strptime->new(
295 pattern => $smalldatetime_format,
298 return $smalldatetime_parser->format_datetime(shift);
305 DBIx::Class::Storage::DBI::MSSQL - Base Class for Microsoft SQL Server support
310 This is the base class for Microsoft SQL Server support, used by
311 L<DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server> and
312 L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>.
314 =head1 IMPLEMENTATION NOTES
316 =head2 IDENTITY information
318 Microsoft SQL Server supports three methods of retrieving the IDENTITY
319 value for inserted row: IDENT_CURRENT, @@IDENTITY, and SCOPE_IDENTITY().
320 SCOPE_IDENTITY is used here because it is the safest. However, it must
321 be called is the same execute statement, not just the same connection.
323 So, this implementation appends a SELECT SCOPE_IDENTITY() statement
324 onto each INSERT to accommodate that requirement.
326 C<SELECT @@IDENTITY> can also be used by issuing:
328 $self->_identity_method('@@identity');
330 it will only be used if SCOPE_IDENTITY() fails.
332 This is more dangerous, as inserting into a table with an on insert trigger that
333 inserts into another table with an identity will give erroneous results on
334 recent versions of SQL Server.
336 =head2 identity insert
338 Be aware that we have tried to make things as simple as possible for our users.
339 For MSSQL that means that when a user tries to create a row, while supplying an
340 explicit value for an autoincrementing column, we will try to issue the
341 appropriate database call to make this possible, namely C<SET IDENTITY_INSERT
342 $table_name ON>. Unfortunately this operation in MSSQL requires the
343 C<db_ddladmin> privilege, which is normally not included in the standard
346 =head2 Ordered Subselects
348 If you attempted the following query (among many others) in Microsoft SQL
352 prefetch => 'relation',
357 You may be surprised to receive an exception. The reason for this is a quirk
358 in the MSSQL engine itself, and sadly doesn't have a sensible workaround due
359 to the way DBIC is built. DBIC can do truly wonderful things with the aid of
360 subselects, and does so automatically when necessary. The list of situations
361 when a subselect is necessary is long and still changes often, so it can not
362 be exhaustively enumerated here. The general rule of thumb is a joined
363 L<has_many|DBIx::Class::Relationship/has_many> relationship with limit/group
364 applied to the left part of the join.
366 In its "pursuit of standards" Microsft SQL Server goes to great lengths to
367 forbid the use of ordered subselects. This breaks a very useful group of
368 searches like "Give me things number 4 to 6 (ordered by name), and prefetch
369 all their relations, no matter how many". While there is a hack which fools
370 the syntax checker, the optimizer may B<still elect to break the subselect>.
371 Testing has determined that while such breakage does occur (the test suite
372 contains an explicit test which demonstrates the problem), it is relative
373 rare. The benefits of ordered subselects are on the other hand too great to be
374 outright disabled for MSSQL.
376 Thus compromise between usability and perfection is the MSSQL-specific
377 L<resultset attribute|DBIx::Class::ResultSet/ATTRIBUTES> C<unsafe_subselect_ok>.
378 It is deliberately not possible to set this on the Storage level, as the user
379 should inspect (and preferably regression-test) the return of every such
380 ResultSet individually. The example above would work if written like:
383 unsafe_subselect_ok => 1,
384 prefetch => 'relation',
389 If it is possible to rewrite the search() in a way that will avoid the need
390 for this flag - you are urged to do so. If DBIC internals insist that an
391 ordered subselect is necessary for an operation, and you believe there is a
392 different/better way to get the same result - please file a bugreport.
396 See L<DBIx::Class/AUTHOR> and L<DBIx::Class/CONTRIBUTORS>.
400 You may distribute this code under the same terms as Perl itself.