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 | |
7b1b2582 |
16 | __PACKAGE__->mk_group_accessors(simple => qw/ |
fabbd5cc |
17 | _identity _identity_method |
7b1b2582 |
18 | /); |
19 | |
d5dedbd6 |
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 | |
5a77aa8b |
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) = $self->next::method (@_); |
54 | |
fabbd5cc |
55 | # SELECT SCOPE_IDENTITY only works within a statement scope. We |
56 | # must try to always use this particular idiom frist, as it is the |
57 | # only one that guarantees retrieving the correct id under high |
58 | # concurrency. When this fails we will fall back to whatever secondary |
59 | # retrieval method is specified in _identity_method, but at this |
60 | # point we don't have many guarantees we will get what we expected. |
61 | # http://msdn.microsoft.com/en-us/library/ms190315.aspx |
62 | # http://davidhayden.com/blog/dave/archive/2006/01/17/2736.aspx |
63 | if ($self->_perform_autoinc_retrieval) { |
384b8bce |
64 | $sql .= "\nSELECT SCOPE_IDENTITY()"; |
5a77aa8b |
65 | } |
66 | |
67 | return ($sql, $bind); |
68 | } |
69 | |
70 | sub _execute { |
71 | my $self = shift; |
72 | my ($op) = @_; |
73 | |
fabbd5cc |
74 | # always list ctx - we need the $sth |
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75 | my ($rv, $sth, @bind) = $self->next::method(@_); |
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76 | |
fabbd5cc |
77 | if ($self->_perform_autoinc_retrieval) { |
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78 | |
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79 | # this should bring back the result of SELECT SCOPE_IDENTITY() we tacked |
80 | # on in _prep_for_execute above |
9780718f |
81 | my ($identity) = try { $sth->fetchrow_array }; |
ed8de058 |
82 | |
1537084d |
83 | # SCOPE_IDENTITY failed, but we can do something else |
84 | if ( (! $identity) && $self->_identity_method) { |
85 | ($identity) = $self->_dbh->selectrow_array( |
86 | 'select ' . $self->_identity_method |
87 | ); |
88 | } |
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89 | |
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90 | $self->_identity($identity); |
91 | $sth->finish; |
7b1b2582 |
92 | } |
93 | |
1537084d |
94 | return wantarray ? ($rv, $sth, @bind) : $rv; |
7b1b2582 |
95 | } |
5a77aa8b |
96 | |
7b1b2582 |
97 | sub last_insert_id { shift->_identity } |
5a77aa8b |
98 | |
f0bd60fc |
99 | # |
e74c68ce |
100 | # MSSQL is retarded wrt ordered subselects. One needs to add a TOP |
6a247f33 |
101 | # to *all* subqueries, but one also *can't* use TOP 100 PERCENT |
e74c68ce |
102 | # http://sqladvice.com/forums/permalink/18496/22931/ShowThread.aspx#22931 |
f0bd60fc |
103 | # |
104 | sub _select_args_to_query { |
105 | my $self = shift; |
106 | |
b8d88d9b |
107 | my ($sql, $prep_bind, @rest) = $self->next::method (@_); |
f0bd60fc |
108 | |
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109 | # see if this is an ordered subquery |
110 | my $attrs = $_[3]; |
aca481d8 |
111 | if ( |
112 | $sql !~ /^ \s* SELECT \s+ TOP \s+ \d+ \s+ /xi |
113 | && |
bac358c9 |
114 | scalar $self->_extract_order_criteria ($attrs->{order_by}) |
aca481d8 |
115 | ) { |
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116 | $self->throw_exception( |
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117 | 'An ordered subselect encountered - this is not safe! Please see "Ordered Subselects" in DBIx::Class::Storage::DBI::MSSQL |
69a8b315 |
118 | ') unless $attrs->{unsafe_subselect_ok}; |
e9657379 |
119 | my $max = $self->sql_maker->__max_int; |
e74c68ce |
120 | $sql =~ s/^ \s* SELECT \s/SELECT TOP $max /xi; |
f0bd60fc |
121 | } |
122 | |
f0bd60fc |
123 | return wantarray |
17555a0c |
124 | ? ($sql, $prep_bind, @rest) |
125 | : \[ "($sql)", @$prep_bind ] |
f0bd60fc |
126 | ; |
127 | } |
128 | |
129 | |
4c0f4206 |
130 | # savepoint syntax is the same as in Sybase ASE |
131 | |
90d7422f |
132 | sub _exec_svp_begin { |
4c0f4206 |
133 | my ($self, $name) = @_; |
134 | |
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135 | $self->_dbh->do("SAVE TRANSACTION $name"); |
4c0f4206 |
136 | } |
137 | |
138 | # A new SAVE TRANSACTION with the same name releases the previous one. |
90d7422f |
139 | sub _exec_svp_release { 1 } |
4c0f4206 |
140 | |
90d7422f |
141 | sub _exec_svp_rollback { |
4c0f4206 |
142 | my ($self, $name) = @_; |
143 | |
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144 | $self->_dbh->do("ROLLBACK TRANSACTION $name"); |
4c0f4206 |
145 | } |
146 | |
eb0323df |
147 | sub sqlt_type { 'SQLServer' } |
148 | |
6a247f33 |
149 | sub sql_limit_dialect { |
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150 | my $self = shift; |
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151 | |
6a247f33 |
152 | my $supports_rno = 0; |
ff153e24 |
153 | |
6a247f33 |
154 | if (exists $self->_server_info->{normalized_dbms_version}) { |
155 | $supports_rno = 1 if $self->_server_info->{normalized_dbms_version} >= 9; |
156 | } |
157 | else { |
158 | # User is connecting via DBD::Sybase and has no permission to run |
159 | # stored procedures like xp_msver, or version detection failed for some |
160 | # other reason. |
161 | # So, we use a query to check if RNO is implemented. |
162 | try { |
163 | $self->_get_dbh->selectrow_array('SELECT row_number() OVER (ORDER BY rand())'); |
164 | $supports_rno = 1; |
165 | }; |
50772633 |
166 | } |
e76e7b5c |
167 | |
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168 | return $supports_rno ? 'RowNumberOver' : 'Top'; |
ed8de058 |
169 | } |
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170 | |
ecdf1ac8 |
171 | sub _ping { |
172 | my $self = shift; |
173 | |
174 | my $dbh = $self->_dbh or return 0; |
175 | |
176 | local $dbh->{RaiseError} = 1; |
177 | local $dbh->{PrintError} = 0; |
178 | |
52b420dd |
179 | return try { |
ecdf1ac8 |
180 | $dbh->do('select 1'); |
52b420dd |
181 | 1; |
ed7ab0f4 |
182 | } catch { |
52b420dd |
183 | 0; |
ecdf1ac8 |
184 | }; |
ecdf1ac8 |
185 | } |
186 | |
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187 | package # hide from PAUSE |
188 | DBIx::Class::Storage::DBI::MSSQL::DateTime::Format; |
189 | |
fd323bf1 |
190 | my $datetime_format = '%Y-%m-%d %H:%M:%S.%3N'; # %F %T |
fb95dc4d |
191 | my $smalldatetime_format = '%Y-%m-%d %H:%M:%S'; |
192 | |
193 | my ($datetime_parser, $smalldatetime_parser); |
194 | |
195 | sub parse_datetime { |
196 | shift; |
197 | require DateTime::Format::Strptime; |
198 | $datetime_parser ||= DateTime::Format::Strptime->new( |
199 | pattern => $datetime_format, |
200 | on_error => 'croak', |
201 | ); |
202 | return $datetime_parser->parse_datetime(shift); |
203 | } |
204 | |
205 | sub format_datetime { |
206 | shift; |
207 | require DateTime::Format::Strptime; |
208 | $datetime_parser ||= DateTime::Format::Strptime->new( |
209 | pattern => $datetime_format, |
210 | on_error => 'croak', |
211 | ); |
212 | return $datetime_parser->format_datetime(shift); |
213 | } |
214 | |
215 | sub parse_smalldatetime { |
216 | shift; |
217 | require DateTime::Format::Strptime; |
218 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
219 | pattern => $smalldatetime_format, |
220 | on_error => 'croak', |
221 | ); |
222 | return $smalldatetime_parser->parse_datetime(shift); |
223 | } |
224 | |
225 | sub format_smalldatetime { |
226 | shift; |
227 | require DateTime::Format::Strptime; |
228 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
229 | pattern => $smalldatetime_format, |
230 | on_error => 'croak', |
231 | ); |
232 | return $smalldatetime_parser->format_datetime(shift); |
233 | } |
234 | |
75d07914 |
235 | 1; |
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236 | |
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237 | =head1 NAME |
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238 | |
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239 | DBIx::Class::Storage::DBI::MSSQL - Base Class for Microsoft SQL Server support |
240 | in DBIx::Class |
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241 | |
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242 | =head1 SYNOPSIS |
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243 | |
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244 | This is the base class for Microsoft SQL Server support, used by |
245 | L<DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server> and |
246 | L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>. |
eb0323df |
247 | |
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248 | =head1 IMPLEMENTATION NOTES |
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249 | |
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250 | =head2 IDENTITY information |
251 | |
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252 | Microsoft SQL Server supports three methods of retrieving the IDENTITY |
253 | value for inserted row: IDENT_CURRENT, @@IDENTITY, and SCOPE_IDENTITY(). |
254 | SCOPE_IDENTITY is used here because it is the safest. However, it must |
255 | be called is the same execute statement, not just the same connection. |
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256 | |
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257 | So, this implementation appends a SELECT SCOPE_IDENTITY() statement |
258 | onto each INSERT to accommodate that requirement. |
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259 | |
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260 | C<SELECT @@IDENTITY> can also be used by issuing: |
261 | |
262 | $self->_identity_method('@@identity'); |
263 | |
08cdc412 |
264 | it will only be used if SCOPE_IDENTITY() fails. |
265 | |
266 | This is more dangerous, as inserting into a table with an on insert trigger that |
267 | inserts into another table with an identity will give erroneous results on |
268 | recent versions of SQL Server. |
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269 | |
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270 | =head2 identity insert |
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271 | |
272 | Be aware that we have tried to make things as simple as possible for our users. |
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273 | For MSSQL that means that when a user tries to create a row, while supplying an |
274 | explicit value for an autoincrementing column, we will try to issue the |
275 | appropriate database call to make this possible, namely C<SET IDENTITY_INSERT |
276 | $table_name ON>. Unfortunately this operation in MSSQL requires the |
277 | C<db_ddladmin> privilege, which is normally not included in the standard |
278 | write-permissions. |
fd05d10a |
279 | |
d74f2da9 |
280 | =head2 Ordered Subselects |
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281 | |
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282 | If you attempted the following query (among many others) in Microsoft SQL |
283 | Server |
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284 | |
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285 | $rs->search ({}, { |
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286 | prefetch => 'relation', |
287 | rows => 2, |
288 | offset => 3, |
289 | }); |
290 | |
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291 | You may be surprised to receive an exception. The reason for this is a quirk |
292 | in the MSSQL engine itself, and sadly doesn't have a sensible workaround due |
293 | to the way DBIC is built. DBIC can do truly wonderful things with the aid of |
294 | subselects, and does so automatically when necessary. The list of situations |
295 | when a subselect is necessary is long and still changes often, so it can not |
296 | be exhaustively enumerated here. The general rule of thumb is a joined |
297 | L<has_many|DBIx::Class::Relationship/has_many> relationship with limit/group |
298 | applied to the left part of the join. |
299 | |
300 | In its "pursuit of standards" Microsft SQL Server goes to great lengths to |
301 | forbid the use of ordered subselects. This breaks a very useful group of |
302 | searches like "Give me things number 4 to 6 (ordered by name), and prefetch |
303 | all their relations, no matter how many". While there is a hack which fools |
304 | the syntax checker, the optimizer may B<still elect to break the subselect>. |
305 | Testing has determined that while such breakage does occur (the test suite |
306 | contains an explicit test which demonstrates the problem), it is relative |
307 | rare. The benefits of ordered subselects are on the other hand too great to be |
308 | outright disabled for MSSQL. |
6de07ea3 |
309 | |
310 | Thus compromise between usability and perfection is the MSSQL-specific |
69a8b315 |
311 | L<resultset attribute|DBIx::Class::ResultSet/ATTRIBUTES> C<unsafe_subselect_ok>. |
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312 | It is deliberately not possible to set this on the Storage level, as the user |
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313 | should inspect (and preferably regression-test) the return of every such |
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314 | ResultSet individually. The example above would work if written like: |
315 | |
316 | $rs->search ({}, { |
69a8b315 |
317 | unsafe_subselect_ok => 1, |
d74f2da9 |
318 | prefetch => 'relation', |
319 | rows => 2, |
320 | offset => 3, |
321 | }); |
6de07ea3 |
322 | |
323 | If it is possible to rewrite the search() in a way that will avoid the need |
324 | for this flag - you are urged to do so. If DBIC internals insist that an |
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325 | ordered subselect is necessary for an operation, and you believe there is a |
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326 | different/better way to get the same result - please file a bugreport. |
6de07ea3 |
327 | |
5a77aa8b |
328 | =head1 AUTHOR |
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329 | |
548d1627 |
330 | See L<DBIx::Class/AUTHOR> and L<DBIx::Class/CONTRIBUTORS>. |
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331 | |
75d07914 |
332 | =head1 LICENSE |
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333 | |
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334 | You may distribute this code under the same terms as Perl itself. |
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335 | |
75d07914 |
336 | =cut |