Commit | Line | Data |
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1 | package DBIx::Class::Storage::DBI::MSSQL; |
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2 | |
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3 | use strict; |
4 | use warnings; |
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5 | |
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6 | use base qw/ |
7 | DBIx::Class::Storage::DBI::UniqueIdentifier |
8 | DBIx::Class::Storage::DBI::IdentityInsert |
9 | /; |
2ad62d97 |
10 | use mro 'c3'; |
fabbd5cc |
11 | |
ed7ab0f4 |
12 | use Try::Tiny; |
6298a324 |
13 | use List::Util 'first'; |
fd323bf1 |
14 | use namespace::clean; |
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15 | |
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16 | __PACKAGE__->mk_group_accessors(simple => qw/ |
25d3127d |
17 | _identity _identity_method _no_scope_identity_query |
7b1b2582 |
18 | /); |
19 | |
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20 | __PACKAGE__->sql_maker_class('DBIx::Class::SQLMaker::MSSQL'); |
ac93965c |
21 | |
2b8cc2f2 |
22 | __PACKAGE__->sql_quote_char([qw/[ ]/]); |
23 | |
6f7a118e |
24 | __PACKAGE__->datetime_parser_type ( |
25 | 'DBIx::Class::Storage::DBI::MSSQL::DateTime::Format' |
26 | ); |
27 | |
40d8d018 |
28 | __PACKAGE__->new_guid('NEWID()'); |
29 | |
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30 | sub _prep_for_execute { |
31 | my $self = shift; |
0e773352 |
32 | my ($op, $ident, $args) = @_; |
5a77aa8b |
33 | |
34 | # cast MONEY values properly |
35 | if ($op eq 'insert' || $op eq 'update') { |
36 | my $fields = $args->[0]; |
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37 | |
52416317 |
38 | my $colinfo = $ident->columns_info([keys %$fields]); |
39 | |
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40 | for my $col (keys %$fields) { |
1537084d |
41 | # $ident is a result source object with INSERT/UPDATE ops |
52416317 |
42 | if ( |
43 | $colinfo->{$col}{data_type} |
44 | && |
45 | $colinfo->{$col}{data_type} =~ /^money\z/i |
46 | ) { |
5a77aa8b |
47 | my $val = $fields->{$col}; |
48 | $fields->{$col} = \['CAST(? AS MONEY)', [ $col => $val ]]; |
49 | } |
50 | } |
51 | } |
52 | |
53 | my ($sql, $bind) = $self->next::method (@_); |
54 | |
fabbd5cc |
55 | # SELECT SCOPE_IDENTITY only works within a statement scope. We |
4a0eed52 |
56 | # must try to always use this particular idiom first, as it is the |
fabbd5cc |
57 | # only one that guarantees retrieving the correct id under high |
58 | # concurrency. When this fails we will fall back to whatever secondary |
59 | # retrieval method is specified in _identity_method, but at this |
60 | # point we don't have many guarantees we will get what we expected. |
61 | # http://msdn.microsoft.com/en-us/library/ms190315.aspx |
62 | # http://davidhayden.com/blog/dave/archive/2006/01/17/2736.aspx |
25d3127d |
63 | if ($self->_perform_autoinc_retrieval and not $self->_no_scope_identity_query) { |
384b8bce |
64 | $sql .= "\nSELECT SCOPE_IDENTITY()"; |
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65 | } |
66 | |
67 | return ($sql, $bind); |
68 | } |
69 | |
70 | sub _execute { |
71 | my $self = shift; |
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72 | |
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73 | # always list ctx - we need the $sth |
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74 | my ($rv, $sth, @bind) = $self->next::method(@_); |
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75 | |
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76 | if ($self->_perform_autoinc_retrieval) { |
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77 | |
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78 | # attempt to bring back the result of SELECT SCOPE_IDENTITY() we tacked |
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79 | # on in _prep_for_execute above |
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80 | my $identity; |
81 | |
82 | # we didn't even try on ftds |
83 | unless ($self->_no_scope_identity_query) { |
84 | ($identity) = try { $sth->fetchrow_array }; |
85 | $sth->finish; |
86 | } |
ed8de058 |
87 | |
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88 | # SCOPE_IDENTITY failed, but we can do something else |
89 | if ( (! $identity) && $self->_identity_method) { |
90 | ($identity) = $self->_dbh->selectrow_array( |
91 | 'select ' . $self->_identity_method |
92 | ); |
93 | } |
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94 | |
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95 | $self->_identity($identity); |
7b1b2582 |
96 | } |
97 | |
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98 | return wantarray ? ($rv, $sth, @bind) : $rv; |
7b1b2582 |
99 | } |
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100 | |
7b1b2582 |
101 | sub last_insert_id { shift->_identity } |
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102 | |
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103 | # |
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104 | # MSSQL is retarded wrt ordered subselects. One needs to add a TOP |
6a247f33 |
105 | # to *all* subqueries, but one also *can't* use TOP 100 PERCENT |
e74c68ce |
106 | # http://sqladvice.com/forums/permalink/18496/22931/ShowThread.aspx#22931 |
f0bd60fc |
107 | # |
108 | sub _select_args_to_query { |
b928a9d5 |
109 | #my ($self, $ident, $select, $cond, $attrs) = @_; |
f0bd60fc |
110 | my $self = shift; |
b928a9d5 |
111 | my $attrs = $_[3]; |
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112 | |
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113 | my $sql_bind = $self->next::method (@_); |
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114 | |
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115 | # see if this is an ordered subquery |
aca481d8 |
116 | if ( |
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117 | $$sql_bind->[0] !~ /^ \s* \( \s* SELECT \s+ TOP \s+ \d+ \s+ /xi |
118 | and |
bac358c9 |
119 | scalar $self->_extract_order_criteria ($attrs->{order_by}) |
aca481d8 |
120 | ) { |
6de07ea3 |
121 | $self->throw_exception( |
e705f529 |
122 | 'An ordered subselect encountered - this is not safe! Please see "Ordered Subselects" in DBIx::Class::Storage::DBI::MSSQL' |
123 | ) unless $attrs->{unsafe_subselect_ok}; |
b928a9d5 |
124 | |
125 | $$sql_bind->[0] =~ s/^ \s* \( \s* SELECT (?=\s) / '(SELECT TOP ' . $self->sql_maker->__max_int /exi; |
f0bd60fc |
126 | } |
127 | |
b928a9d5 |
128 | $sql_bind; |
f0bd60fc |
129 | } |
130 | |
131 | |
4c0f4206 |
132 | # savepoint syntax is the same as in Sybase ASE |
133 | |
90d7422f |
134 | sub _exec_svp_begin { |
4c0f4206 |
135 | my ($self, $name) = @_; |
136 | |
90d7422f |
137 | $self->_dbh->do("SAVE TRANSACTION $name"); |
4c0f4206 |
138 | } |
139 | |
140 | # A new SAVE TRANSACTION with the same name releases the previous one. |
90d7422f |
141 | sub _exec_svp_release { 1 } |
4c0f4206 |
142 | |
90d7422f |
143 | sub _exec_svp_rollback { |
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144 | my ($self, $name) = @_; |
145 | |
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146 | $self->_dbh->do("ROLLBACK TRANSACTION $name"); |
4c0f4206 |
147 | } |
148 | |
eb0323df |
149 | sub sqlt_type { 'SQLServer' } |
150 | |
6a247f33 |
151 | sub sql_limit_dialect { |
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152 | my $self = shift; |
eb0323df |
153 | |
6a247f33 |
154 | my $supports_rno = 0; |
ff153e24 |
155 | |
6a247f33 |
156 | if (exists $self->_server_info->{normalized_dbms_version}) { |
157 | $supports_rno = 1 if $self->_server_info->{normalized_dbms_version} >= 9; |
158 | } |
159 | else { |
160 | # User is connecting via DBD::Sybase and has no permission to run |
161 | # stored procedures like xp_msver, or version detection failed for some |
162 | # other reason. |
163 | # So, we use a query to check if RNO is implemented. |
164 | try { |
165 | $self->_get_dbh->selectrow_array('SELECT row_number() OVER (ORDER BY rand())'); |
166 | $supports_rno = 1; |
167 | }; |
50772633 |
168 | } |
e76e7b5c |
169 | |
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170 | return $supports_rno ? 'RowNumberOver' : 'Top'; |
ed8de058 |
171 | } |
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172 | |
ecdf1ac8 |
173 | sub _ping { |
174 | my $self = shift; |
175 | |
176 | my $dbh = $self->_dbh or return 0; |
177 | |
178 | local $dbh->{RaiseError} = 1; |
179 | local $dbh->{PrintError} = 0; |
180 | |
52b420dd |
181 | return try { |
ecdf1ac8 |
182 | $dbh->do('select 1'); |
52b420dd |
183 | 1; |
ed7ab0f4 |
184 | } catch { |
52b420dd |
185 | 0; |
ecdf1ac8 |
186 | }; |
ecdf1ac8 |
187 | } |
188 | |
fb95dc4d |
189 | package # hide from PAUSE |
190 | DBIx::Class::Storage::DBI::MSSQL::DateTime::Format; |
191 | |
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192 | my $datetime_format = '%Y-%m-%d %H:%M:%S.%3N'; # %F %T |
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193 | my $smalldatetime_format = '%Y-%m-%d %H:%M:%S'; |
194 | |
195 | my ($datetime_parser, $smalldatetime_parser); |
196 | |
197 | sub parse_datetime { |
198 | shift; |
199 | require DateTime::Format::Strptime; |
200 | $datetime_parser ||= DateTime::Format::Strptime->new( |
201 | pattern => $datetime_format, |
202 | on_error => 'croak', |
203 | ); |
204 | return $datetime_parser->parse_datetime(shift); |
205 | } |
206 | |
207 | sub format_datetime { |
208 | shift; |
209 | require DateTime::Format::Strptime; |
210 | $datetime_parser ||= DateTime::Format::Strptime->new( |
211 | pattern => $datetime_format, |
212 | on_error => 'croak', |
213 | ); |
214 | return $datetime_parser->format_datetime(shift); |
215 | } |
216 | |
217 | sub parse_smalldatetime { |
218 | shift; |
219 | require DateTime::Format::Strptime; |
220 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
221 | pattern => $smalldatetime_format, |
222 | on_error => 'croak', |
223 | ); |
224 | return $smalldatetime_parser->parse_datetime(shift); |
225 | } |
226 | |
227 | sub format_smalldatetime { |
228 | shift; |
229 | require DateTime::Format::Strptime; |
230 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
231 | pattern => $smalldatetime_format, |
232 | on_error => 'croak', |
233 | ); |
234 | return $smalldatetime_parser->format_datetime(shift); |
235 | } |
236 | |
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237 | 1; |
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238 | |
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239 | =head1 NAME |
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240 | |
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241 | DBIx::Class::Storage::DBI::MSSQL - Base Class for Microsoft SQL Server support |
242 | in DBIx::Class |
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243 | |
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244 | =head1 SYNOPSIS |
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245 | |
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246 | This is the base class for Microsoft SQL Server support, used by |
247 | L<DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server> and |
248 | L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>. |
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249 | |
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250 | =head1 IMPLEMENTATION NOTES |
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251 | |
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252 | =head2 IDENTITY information |
253 | |
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254 | Microsoft SQL Server supports three methods of retrieving the IDENTITY |
255 | value for inserted row: IDENT_CURRENT, @@IDENTITY, and SCOPE_IDENTITY(). |
256 | SCOPE_IDENTITY is used here because it is the safest. However, it must |
257 | be called is the same execute statement, not just the same connection. |
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258 | |
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259 | So, this implementation appends a SELECT SCOPE_IDENTITY() statement |
260 | onto each INSERT to accommodate that requirement. |
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261 | |
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262 | C<SELECT @@IDENTITY> can also be used by issuing: |
263 | |
264 | $self->_identity_method('@@identity'); |
265 | |
08cdc412 |
266 | it will only be used if SCOPE_IDENTITY() fails. |
267 | |
268 | This is more dangerous, as inserting into a table with an on insert trigger that |
269 | inserts into another table with an identity will give erroneous results on |
270 | recent versions of SQL Server. |
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271 | |
c84189e1 |
272 | =head2 identity insert |
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273 | |
274 | Be aware that we have tried to make things as simple as possible for our users. |
c84189e1 |
275 | For MSSQL that means that when a user tries to create a row, while supplying an |
276 | explicit value for an autoincrementing column, we will try to issue the |
277 | appropriate database call to make this possible, namely C<SET IDENTITY_INSERT |
278 | $table_name ON>. Unfortunately this operation in MSSQL requires the |
279 | C<db_ddladmin> privilege, which is normally not included in the standard |
280 | write-permissions. |
fd05d10a |
281 | |
d74f2da9 |
282 | =head2 Ordered Subselects |
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283 | |
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284 | If you attempted the following query (among many others) in Microsoft SQL |
285 | Server |
6de07ea3 |
286 | |
6de07ea3 |
287 | $rs->search ({}, { |
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288 | prefetch => 'relation', |
289 | rows => 2, |
290 | offset => 3, |
291 | }); |
292 | |
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293 | You may be surprised to receive an exception. The reason for this is a quirk |
294 | in the MSSQL engine itself, and sadly doesn't have a sensible workaround due |
295 | to the way DBIC is built. DBIC can do truly wonderful things with the aid of |
296 | subselects, and does so automatically when necessary. The list of situations |
297 | when a subselect is necessary is long and still changes often, so it can not |
298 | be exhaustively enumerated here. The general rule of thumb is a joined |
299 | L<has_many|DBIx::Class::Relationship/has_many> relationship with limit/group |
300 | applied to the left part of the join. |
301 | |
302 | In its "pursuit of standards" Microsft SQL Server goes to great lengths to |
303 | forbid the use of ordered subselects. This breaks a very useful group of |
304 | searches like "Give me things number 4 to 6 (ordered by name), and prefetch |
305 | all their relations, no matter how many". While there is a hack which fools |
306 | the syntax checker, the optimizer may B<still elect to break the subselect>. |
307 | Testing has determined that while such breakage does occur (the test suite |
308 | contains an explicit test which demonstrates the problem), it is relative |
309 | rare. The benefits of ordered subselects are on the other hand too great to be |
310 | outright disabled for MSSQL. |
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311 | |
312 | Thus compromise between usability and perfection is the MSSQL-specific |
69a8b315 |
313 | L<resultset attribute|DBIx::Class::ResultSet/ATTRIBUTES> C<unsafe_subselect_ok>. |
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314 | It is deliberately not possible to set this on the Storage level, as the user |
48580715 |
315 | should inspect (and preferably regression-test) the return of every such |
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316 | ResultSet individually. The example above would work if written like: |
317 | |
318 | $rs->search ({}, { |
69a8b315 |
319 | unsafe_subselect_ok => 1, |
d74f2da9 |
320 | prefetch => 'relation', |
321 | rows => 2, |
322 | offset => 3, |
323 | }); |
6de07ea3 |
324 | |
325 | If it is possible to rewrite the search() in a way that will avoid the need |
326 | for this flag - you are urged to do so. If DBIC internals insist that an |
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327 | ordered subselect is necessary for an operation, and you believe there is a |
48580715 |
328 | different/better way to get the same result - please file a bugreport. |
6de07ea3 |
329 | |
5a77aa8b |
330 | =head1 AUTHOR |
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331 | |
548d1627 |
332 | See L<DBIx::Class/AUTHOR> and L<DBIx::Class/CONTRIBUTORS>. |
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333 | |
75d07914 |
334 | =head1 LICENSE |
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335 | |
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336 | You may distribute this code under the same terms as Perl itself. |
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337 | |
75d07914 |
338 | =cut |