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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/DBIx::Class::Storage::DBI::UniqueIdentifier/; |
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7 | use mro 'c3'; |
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8 | use Try::Tiny; |
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9 | use List::Util 'first'; |
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10 | use namespace::clean; |
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11 | |
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12 | __PACKAGE__->mk_group_accessors(simple => qw/ |
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13 | _identity _identity_method _pre_insert_sql _post_insert_sql |
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14 | /); |
15 | |
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16 | __PACKAGE__->sql_maker_class('DBIx::Class::SQLMaker::MSSQL'); |
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17 | |
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18 | sub _set_identity_insert { |
19 | my ($self, $table) = @_; |
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20 | |
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21 | my $stmt = 'SET IDENTITY_INSERT %s %s'; |
22 | $table = $self->sql_maker->_quote($table); |
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23 | |
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24 | $self->_pre_insert_sql (sprintf $stmt, $table, 'ON'); |
25 | $self->_post_insert_sql(sprintf $stmt, $table, 'OFF'); |
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26 | } |
27 | |
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28 | sub insert_bulk { |
29 | my $self = shift; |
30 | my ($source, $cols, $data) = @_; |
31 | |
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32 | my $is_identity_insert = |
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33 | (first { $_->{is_auto_increment} } values %{ $source->columns_info($cols) } ) |
34 | ? 1 |
35 | : 0 |
36 | ; |
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37 | |
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38 | if ($is_identity_insert) { |
39 | $self->_set_identity_insert ($source->name); |
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40 | } |
41 | |
42 | $self->next::method(@_); |
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43 | } |
44 | |
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45 | sub insert { |
46 | my $self = shift; |
47 | my ($source, $to_insert) = @_; |
48 | |
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49 | my $supplied_col_info = $self->_resolve_column_info($source, [keys %$to_insert] ); |
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50 | |
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51 | my $is_identity_insert = |
52 | (first { $_->{is_auto_increment} } values %$supplied_col_info) ? 1 : 0; |
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53 | |
54 | if ($is_identity_insert) { |
55 | $self->_set_identity_insert ($source->name); |
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56 | } |
57 | |
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58 | my $updated_cols = $self->next::method(@_); |
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59 | |
60 | return $updated_cols; |
61 | } |
62 | |
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63 | sub _prep_for_execute { |
64 | my $self = shift; |
65 | my ($op, $extra_bind, $ident, $args) = @_; |
66 | |
67 | # cast MONEY values properly |
68 | if ($op eq 'insert' || $op eq 'update') { |
69 | my $fields = $args->[0]; |
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70 | |
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71 | my $colinfo = $ident->columns_info([keys %$fields]); |
72 | |
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73 | for my $col (keys %$fields) { |
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74 | # $ident is a result source object with INSERT/UPDATE ops |
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75 | if ( |
76 | $colinfo->{$col}{data_type} |
77 | && |
78 | $colinfo->{$col}{data_type} =~ /^money\z/i |
79 | ) { |
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80 | my $val = $fields->{$col}; |
81 | $fields->{$col} = \['CAST(? AS MONEY)', [ $col => $val ]]; |
82 | } |
83 | } |
84 | } |
85 | |
86 | my ($sql, $bind) = $self->next::method (@_); |
87 | |
88 | if ($op eq 'insert') { |
384b8bce |
89 | if (my $prepend = $self->_pre_insert_sql) { |
90 | $sql = "${prepend}\n${sql}"; |
91 | $self->_pre_insert_sql(undef); |
92 | } |
93 | if (my $append = $self->_post_insert_sql) { |
94 | $sql = "${sql}\n${append}"; |
95 | $self->_post_insert_sql(undef); |
96 | } |
97 | $sql .= "\nSELECT SCOPE_IDENTITY()"; |
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98 | } |
99 | |
100 | return ($sql, $bind); |
101 | } |
102 | |
103 | sub _execute { |
104 | my $self = shift; |
105 | my ($op) = @_; |
106 | |
107 | my ($rv, $sth, @bind) = $self->dbh_do($self->can('_dbh_execute'), @_); |
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108 | |
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109 | if ($op eq 'insert') { |
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110 | |
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111 | # this should bring back the result of SELECT SCOPE_IDENTITY() we tacked |
112 | # on in _prep_for_execute above |
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113 | my ($identity) = try { $sth->fetchrow_array }; |
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114 | |
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115 | # SCOPE_IDENTITY failed, but we can do something else |
116 | if ( (! $identity) && $self->_identity_method) { |
117 | ($identity) = $self->_dbh->selectrow_array( |
118 | 'select ' . $self->_identity_method |
119 | ); |
120 | } |
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121 | |
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122 | $self->_identity($identity); |
123 | $sth->finish; |
7b1b2582 |
124 | } |
125 | |
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126 | return wantarray ? ($rv, $sth, @bind) : $rv; |
7b1b2582 |
127 | } |
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128 | |
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129 | sub last_insert_id { shift->_identity } |
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130 | |
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131 | # |
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132 | # MSSQL is retarded wrt ordered subselects. One needs to add a TOP |
6a247f33 |
133 | # to *all* subqueries, but one also *can't* use TOP 100 PERCENT |
e74c68ce |
134 | # http://sqladvice.com/forums/permalink/18496/22931/ShowThread.aspx#22931 |
f0bd60fc |
135 | # |
136 | sub _select_args_to_query { |
137 | my $self = shift; |
138 | |
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139 | my ($sql, $prep_bind, @rest) = $self->next::method (@_); |
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140 | |
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141 | # see if this is an ordered subquery |
142 | my $attrs = $_[3]; |
aca481d8 |
143 | if ( |
144 | $sql !~ /^ \s* SELECT \s+ TOP \s+ \d+ \s+ /xi |
145 | && |
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146 | scalar $self->_extract_order_criteria ($attrs->{order_by}) |
aca481d8 |
147 | ) { |
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148 | $self->throw_exception( |
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149 | 'An ordered subselect encountered - this is not safe! Please see "Ordered Subselects" in DBIx::Class::Storage::DBI::MSSQL |
69a8b315 |
150 | ') unless $attrs->{unsafe_subselect_ok}; |
e9657379 |
151 | my $max = $self->sql_maker->__max_int; |
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152 | $sql =~ s/^ \s* SELECT \s/SELECT TOP $max /xi; |
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153 | } |
154 | |
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155 | return wantarray |
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156 | ? ($sql, $prep_bind, @rest) |
157 | : \[ "($sql)", @$prep_bind ] |
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158 | ; |
159 | } |
160 | |
161 | |
4c0f4206 |
162 | # savepoint syntax is the same as in Sybase ASE |
163 | |
164 | sub _svp_begin { |
165 | my ($self, $name) = @_; |
166 | |
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167 | $self->_get_dbh->do("SAVE TRANSACTION $name"); |
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168 | } |
169 | |
170 | # A new SAVE TRANSACTION with the same name releases the previous one. |
171 | sub _svp_release { 1 } |
172 | |
173 | sub _svp_rollback { |
174 | my ($self, $name) = @_; |
175 | |
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176 | $self->_get_dbh->do("ROLLBACK TRANSACTION $name"); |
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177 | } |
178 | |
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179 | sub datetime_parser_type { |
180 | 'DBIx::Class::Storage::DBI::MSSQL::DateTime::Format' |
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181 | } |
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182 | |
183 | sub sqlt_type { 'SQLServer' } |
184 | |
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185 | sub sql_limit_dialect { |
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186 | my $self = shift; |
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187 | |
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188 | my $supports_rno = 0; |
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189 | |
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190 | if (exists $self->_server_info->{normalized_dbms_version}) { |
191 | $supports_rno = 1 if $self->_server_info->{normalized_dbms_version} >= 9; |
192 | } |
193 | else { |
194 | # User is connecting via DBD::Sybase and has no permission to run |
195 | # stored procedures like xp_msver, or version detection failed for some |
196 | # other reason. |
197 | # So, we use a query to check if RNO is implemented. |
198 | try { |
199 | $self->_get_dbh->selectrow_array('SELECT row_number() OVER (ORDER BY rand())'); |
200 | $supports_rno = 1; |
201 | }; |
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202 | } |
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203 | |
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204 | return $supports_rno ? 'RowNumberOver' : 'Top'; |
ed8de058 |
205 | } |
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206 | |
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207 | sub _ping { |
208 | my $self = shift; |
209 | |
210 | my $dbh = $self->_dbh or return 0; |
211 | |
212 | local $dbh->{RaiseError} = 1; |
213 | local $dbh->{PrintError} = 0; |
214 | |
52b420dd |
215 | return try { |
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216 | $dbh->do('select 1'); |
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217 | 1; |
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218 | } catch { |
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219 | 0; |
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220 | }; |
ecdf1ac8 |
221 | } |
222 | |
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223 | package # hide from PAUSE |
224 | DBIx::Class::Storage::DBI::MSSQL::DateTime::Format; |
225 | |
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226 | my $datetime_format = '%Y-%m-%d %H:%M:%S.%3N'; # %F %T |
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227 | my $smalldatetime_format = '%Y-%m-%d %H:%M:%S'; |
228 | |
229 | my ($datetime_parser, $smalldatetime_parser); |
230 | |
231 | sub parse_datetime { |
232 | shift; |
233 | require DateTime::Format::Strptime; |
234 | $datetime_parser ||= DateTime::Format::Strptime->new( |
235 | pattern => $datetime_format, |
236 | on_error => 'croak', |
237 | ); |
238 | return $datetime_parser->parse_datetime(shift); |
239 | } |
240 | |
241 | sub format_datetime { |
242 | shift; |
243 | require DateTime::Format::Strptime; |
244 | $datetime_parser ||= DateTime::Format::Strptime->new( |
245 | pattern => $datetime_format, |
246 | on_error => 'croak', |
247 | ); |
248 | return $datetime_parser->format_datetime(shift); |
249 | } |
250 | |
251 | sub parse_smalldatetime { |
252 | shift; |
253 | require DateTime::Format::Strptime; |
254 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
255 | pattern => $smalldatetime_format, |
256 | on_error => 'croak', |
257 | ); |
258 | return $smalldatetime_parser->parse_datetime(shift); |
259 | } |
260 | |
261 | sub format_smalldatetime { |
262 | shift; |
263 | require DateTime::Format::Strptime; |
264 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
265 | pattern => $smalldatetime_format, |
266 | on_error => 'croak', |
267 | ); |
268 | return $smalldatetime_parser->format_datetime(shift); |
269 | } |
270 | |
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271 | 1; |
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272 | |
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273 | =head1 NAME |
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274 | |
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275 | DBIx::Class::Storage::DBI::MSSQL - Base Class for Microsoft SQL Server support |
276 | in DBIx::Class |
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277 | |
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278 | =head1 SYNOPSIS |
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279 | |
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280 | This is the base class for Microsoft SQL Server support, used by |
281 | L<DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server> and |
282 | L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>. |
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283 | |
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284 | =head1 IMPLEMENTATION NOTES |
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285 | |
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286 | =head2 IDENTITY information |
287 | |
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288 | Microsoft SQL Server supports three methods of retrieving the IDENTITY |
289 | value for inserted row: IDENT_CURRENT, @@IDENTITY, and SCOPE_IDENTITY(). |
290 | SCOPE_IDENTITY is used here because it is the safest. However, it must |
291 | be called is the same execute statement, not just the same connection. |
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292 | |
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293 | So, this implementation appends a SELECT SCOPE_IDENTITY() statement |
294 | onto each INSERT to accommodate that requirement. |
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295 | |
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296 | C<SELECT @@IDENTITY> can also be used by issuing: |
297 | |
298 | $self->_identity_method('@@identity'); |
299 | |
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300 | it will only be used if SCOPE_IDENTITY() fails. |
301 | |
302 | This is more dangerous, as inserting into a table with an on insert trigger that |
303 | inserts into another table with an identity will give erroneous results on |
304 | recent versions of SQL Server. |
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305 | |
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306 | =head2 identity insert |
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307 | |
308 | Be aware that we have tried to make things as simple as possible for our users. |
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309 | For MSSQL that means that when a user tries to create a row, while supplying an |
310 | explicit value for an autoincrementing column, we will try to issue the |
311 | appropriate database call to make this possible, namely C<SET IDENTITY_INSERT |
312 | $table_name ON>. Unfortunately this operation in MSSQL requires the |
313 | C<db_ddladmin> privilege, which is normally not included in the standard |
314 | write-permissions. |
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315 | |
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316 | =head2 Ordered Subselects |
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317 | |
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318 | If you attempted the following query (among many others) in Microsoft SQL |
319 | Server |
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320 | |
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321 | $rs->search ({}, { |
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322 | prefetch => 'relation', |
323 | rows => 2, |
324 | offset => 3, |
325 | }); |
326 | |
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327 | You may be surprised to receive an exception. The reason for this is a quirk |
328 | in the MSSQL engine itself, and sadly doesn't have a sensible workaround due |
329 | to the way DBIC is built. DBIC can do truly wonderful things with the aid of |
330 | subselects, and does so automatically when necessary. The list of situations |
331 | when a subselect is necessary is long and still changes often, so it can not |
332 | be exhaustively enumerated here. The general rule of thumb is a joined |
333 | L<has_many|DBIx::Class::Relationship/has_many> relationship with limit/group |
334 | applied to the left part of the join. |
335 | |
336 | In its "pursuit of standards" Microsft SQL Server goes to great lengths to |
337 | forbid the use of ordered subselects. This breaks a very useful group of |
338 | searches like "Give me things number 4 to 6 (ordered by name), and prefetch |
339 | all their relations, no matter how many". While there is a hack which fools |
340 | the syntax checker, the optimizer may B<still elect to break the subselect>. |
341 | Testing has determined that while such breakage does occur (the test suite |
342 | contains an explicit test which demonstrates the problem), it is relative |
343 | rare. The benefits of ordered subselects are on the other hand too great to be |
344 | outright disabled for MSSQL. |
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345 | |
346 | Thus compromise between usability and perfection is the MSSQL-specific |
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347 | L<resultset attribute|DBIx::Class::ResultSet/ATTRIBUTES> C<unsafe_subselect_ok>. |
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348 | It is deliberately not possible to set this on the Storage level, as the user |
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349 | should inspect (and preferably regression-test) the return of every such |
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350 | ResultSet individually. The example above would work if written like: |
351 | |
352 | $rs->search ({}, { |
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353 | unsafe_subselect_ok => 1, |
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354 | prefetch => 'relation', |
355 | rows => 2, |
356 | offset => 3, |
357 | }); |
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358 | |
359 | If it is possible to rewrite the search() in a way that will avoid the need |
360 | for this flag - you are urged to do so. If DBIC internals insist that an |
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361 | ordered subselect is necessary for an operation, and you believe there is a |
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362 | different/better way to get the same result - please file a bugreport. |
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363 | |
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364 | =head1 AUTHOR |
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365 | |
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366 | See L<DBIx::Class/AUTHOR> and L<DBIx::Class/CONTRIBUTORS>. |
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367 | |
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368 | =head1 LICENSE |
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369 | |
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370 | You may distribute this code under the same terms as Perl itself. |
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371 | |
75d07914 |
372 | =cut |