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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 | __PACKAGE__->sql_quote_char([qw/[ ]/]); |
19 | |
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20 | sub _set_identity_insert { |
21 | my ($self, $table) = @_; |
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22 | |
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23 | my $stmt = 'SET IDENTITY_INSERT %s %s'; |
24 | $table = $self->sql_maker->_quote($table); |
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25 | |
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26 | $self->_pre_insert_sql (sprintf $stmt, $table, 'ON'); |
27 | $self->_post_insert_sql(sprintf $stmt, $table, 'OFF'); |
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28 | } |
29 | |
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30 | sub insert_bulk { |
31 | my $self = shift; |
32 | my ($source, $cols, $data) = @_; |
33 | |
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34 | my $is_identity_insert = |
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35 | (first { $_->{is_auto_increment} } values %{ $source->columns_info($cols) } ) |
36 | ? 1 |
37 | : 0 |
38 | ; |
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39 | |
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40 | if ($is_identity_insert) { |
41 | $self->_set_identity_insert ($source->name); |
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42 | } |
43 | |
44 | $self->next::method(@_); |
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45 | } |
46 | |
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47 | sub insert { |
48 | my $self = shift; |
49 | my ($source, $to_insert) = @_; |
50 | |
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51 | my $supplied_col_info = $self->_resolve_column_info($source, [keys %$to_insert] ); |
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52 | |
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53 | my $is_identity_insert = |
54 | (first { $_->{is_auto_increment} } values %$supplied_col_info) ? 1 : 0; |
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55 | |
56 | if ($is_identity_insert) { |
57 | $self->_set_identity_insert ($source->name); |
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58 | } |
59 | |
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60 | my $updated_cols = $self->next::method(@_); |
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61 | |
62 | return $updated_cols; |
63 | } |
64 | |
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65 | sub _prep_for_execute { |
66 | my $self = shift; |
67 | my ($op, $extra_bind, $ident, $args) = @_; |
68 | |
69 | # cast MONEY values properly |
70 | if ($op eq 'insert' || $op eq 'update') { |
71 | my $fields = $args->[0]; |
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72 | |
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73 | my $colinfo = $ident->columns_info([keys %$fields]); |
74 | |
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75 | for my $col (keys %$fields) { |
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76 | # $ident is a result source object with INSERT/UPDATE ops |
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77 | if ( |
78 | $colinfo->{$col}{data_type} |
79 | && |
80 | $colinfo->{$col}{data_type} =~ /^money\z/i |
81 | ) { |
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82 | my $val = $fields->{$col}; |
83 | $fields->{$col} = \['CAST(? AS MONEY)', [ $col => $val ]]; |
84 | } |
85 | } |
86 | } |
87 | |
88 | my ($sql, $bind) = $self->next::method (@_); |
89 | |
90 | if ($op eq 'insert') { |
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91 | if (my $prepend = $self->_pre_insert_sql) { |
92 | $sql = "${prepend}\n${sql}"; |
93 | $self->_pre_insert_sql(undef); |
94 | } |
95 | if (my $append = $self->_post_insert_sql) { |
96 | $sql = "${sql}\n${append}"; |
97 | $self->_post_insert_sql(undef); |
98 | } |
99 | $sql .= "\nSELECT SCOPE_IDENTITY()"; |
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100 | } |
101 | |
102 | return ($sql, $bind); |
103 | } |
104 | |
105 | sub _execute { |
106 | my $self = shift; |
107 | my ($op) = @_; |
108 | |
109 | my ($rv, $sth, @bind) = $self->dbh_do($self->can('_dbh_execute'), @_); |
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110 | |
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111 | if ($op eq 'insert') { |
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112 | |
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113 | # this should bring back the result of SELECT SCOPE_IDENTITY() we tacked |
114 | # on in _prep_for_execute above |
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115 | my ($identity) = try { $sth->fetchrow_array }; |
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116 | |
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117 | # SCOPE_IDENTITY failed, but we can do something else |
118 | if ( (! $identity) && $self->_identity_method) { |
119 | ($identity) = $self->_dbh->selectrow_array( |
120 | 'select ' . $self->_identity_method |
121 | ); |
122 | } |
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123 | |
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124 | $self->_identity($identity); |
125 | $sth->finish; |
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126 | } |
127 | |
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128 | return wantarray ? ($rv, $sth, @bind) : $rv; |
7b1b2582 |
129 | } |
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130 | |
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131 | sub last_insert_id { shift->_identity } |
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132 | |
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133 | # |
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134 | # MSSQL is retarded wrt ordered subselects. One needs to add a TOP |
6a247f33 |
135 | # to *all* subqueries, but one also *can't* use TOP 100 PERCENT |
e74c68ce |
136 | # http://sqladvice.com/forums/permalink/18496/22931/ShowThread.aspx#22931 |
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137 | # |
138 | sub _select_args_to_query { |
139 | my $self = shift; |
140 | |
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141 | my ($sql, $prep_bind, @rest) = $self->next::method (@_); |
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142 | |
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143 | # see if this is an ordered subquery |
144 | my $attrs = $_[3]; |
aca481d8 |
145 | if ( |
146 | $sql !~ /^ \s* SELECT \s+ TOP \s+ \d+ \s+ /xi |
147 | && |
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148 | scalar $self->_extract_order_criteria ($attrs->{order_by}) |
aca481d8 |
149 | ) { |
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150 | $self->throw_exception( |
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151 | 'An ordered subselect encountered - this is not safe! Please see "Ordered Subselects" in DBIx::Class::Storage::DBI::MSSQL |
69a8b315 |
152 | ') unless $attrs->{unsafe_subselect_ok}; |
e9657379 |
153 | my $max = $self->sql_maker->__max_int; |
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154 | $sql =~ s/^ \s* SELECT \s/SELECT TOP $max /xi; |
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155 | } |
156 | |
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157 | return wantarray |
17555a0c |
158 | ? ($sql, $prep_bind, @rest) |
159 | : \[ "($sql)", @$prep_bind ] |
f0bd60fc |
160 | ; |
161 | } |
162 | |
163 | |
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164 | # savepoint syntax is the same as in Sybase ASE |
165 | |
166 | sub _svp_begin { |
167 | my ($self, $name) = @_; |
168 | |
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169 | $self->_get_dbh->do("SAVE TRANSACTION $name"); |
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170 | } |
171 | |
172 | # A new SAVE TRANSACTION with the same name releases the previous one. |
173 | sub _svp_release { 1 } |
174 | |
175 | sub _svp_rollback { |
176 | my ($self, $name) = @_; |
177 | |
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178 | $self->_get_dbh->do("ROLLBACK TRANSACTION $name"); |
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179 | } |
180 | |
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181 | sub datetime_parser_type { |
182 | 'DBIx::Class::Storage::DBI::MSSQL::DateTime::Format' |
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183 | } |
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184 | |
185 | sub sqlt_type { 'SQLServer' } |
186 | |
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187 | sub sql_limit_dialect { |
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188 | my $self = shift; |
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189 | |
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190 | my $supports_rno = 0; |
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191 | |
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192 | if (exists $self->_server_info->{normalized_dbms_version}) { |
193 | $supports_rno = 1 if $self->_server_info->{normalized_dbms_version} >= 9; |
194 | } |
195 | else { |
196 | # User is connecting via DBD::Sybase and has no permission to run |
197 | # stored procedures like xp_msver, or version detection failed for some |
198 | # other reason. |
199 | # So, we use a query to check if RNO is implemented. |
200 | try { |
201 | $self->_get_dbh->selectrow_array('SELECT row_number() OVER (ORDER BY rand())'); |
202 | $supports_rno = 1; |
203 | }; |
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204 | } |
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205 | |
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206 | return $supports_rno ? 'RowNumberOver' : 'Top'; |
ed8de058 |
207 | } |
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208 | |
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209 | sub _ping { |
210 | my $self = shift; |
211 | |
212 | my $dbh = $self->_dbh or return 0; |
213 | |
214 | local $dbh->{RaiseError} = 1; |
215 | local $dbh->{PrintError} = 0; |
216 | |
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217 | return try { |
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218 | $dbh->do('select 1'); |
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219 | 1; |
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220 | } catch { |
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221 | 0; |
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222 | }; |
ecdf1ac8 |
223 | } |
224 | |
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225 | package # hide from PAUSE |
226 | DBIx::Class::Storage::DBI::MSSQL::DateTime::Format; |
227 | |
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228 | my $datetime_format = '%Y-%m-%d %H:%M:%S.%3N'; # %F %T |
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229 | my $smalldatetime_format = '%Y-%m-%d %H:%M:%S'; |
230 | |
231 | my ($datetime_parser, $smalldatetime_parser); |
232 | |
233 | sub parse_datetime { |
234 | shift; |
235 | require DateTime::Format::Strptime; |
236 | $datetime_parser ||= DateTime::Format::Strptime->new( |
237 | pattern => $datetime_format, |
238 | on_error => 'croak', |
239 | ); |
240 | return $datetime_parser->parse_datetime(shift); |
241 | } |
242 | |
243 | sub format_datetime { |
244 | shift; |
245 | require DateTime::Format::Strptime; |
246 | $datetime_parser ||= DateTime::Format::Strptime->new( |
247 | pattern => $datetime_format, |
248 | on_error => 'croak', |
249 | ); |
250 | return $datetime_parser->format_datetime(shift); |
251 | } |
252 | |
253 | sub parse_smalldatetime { |
254 | shift; |
255 | require DateTime::Format::Strptime; |
256 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
257 | pattern => $smalldatetime_format, |
258 | on_error => 'croak', |
259 | ); |
260 | return $smalldatetime_parser->parse_datetime(shift); |
261 | } |
262 | |
263 | sub format_smalldatetime { |
264 | shift; |
265 | require DateTime::Format::Strptime; |
266 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
267 | pattern => $smalldatetime_format, |
268 | on_error => 'croak', |
269 | ); |
270 | return $smalldatetime_parser->format_datetime(shift); |
271 | } |
272 | |
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273 | 1; |
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274 | |
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275 | =head1 NAME |
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276 | |
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277 | DBIx::Class::Storage::DBI::MSSQL - Base Class for Microsoft SQL Server support |
278 | in DBIx::Class |
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279 | |
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280 | =head1 SYNOPSIS |
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281 | |
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282 | This is the base class for Microsoft SQL Server support, used by |
283 | L<DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server> and |
284 | L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>. |
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285 | |
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286 | =head1 IMPLEMENTATION NOTES |
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287 | |
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288 | =head2 IDENTITY information |
289 | |
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290 | Microsoft SQL Server supports three methods of retrieving the IDENTITY |
291 | value for inserted row: IDENT_CURRENT, @@IDENTITY, and SCOPE_IDENTITY(). |
292 | SCOPE_IDENTITY is used here because it is the safest. However, it must |
293 | be called is the same execute statement, not just the same connection. |
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294 | |
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295 | So, this implementation appends a SELECT SCOPE_IDENTITY() statement |
296 | onto each INSERT to accommodate that requirement. |
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297 | |
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298 | C<SELECT @@IDENTITY> can also be used by issuing: |
299 | |
300 | $self->_identity_method('@@identity'); |
301 | |
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302 | it will only be used if SCOPE_IDENTITY() fails. |
303 | |
304 | This is more dangerous, as inserting into a table with an on insert trigger that |
305 | inserts into another table with an identity will give erroneous results on |
306 | recent versions of SQL Server. |
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307 | |
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308 | =head2 identity insert |
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309 | |
310 | Be aware that we have tried to make things as simple as possible for our users. |
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311 | For MSSQL that means that when a user tries to create a row, while supplying an |
312 | explicit value for an autoincrementing column, we will try to issue the |
313 | appropriate database call to make this possible, namely C<SET IDENTITY_INSERT |
314 | $table_name ON>. Unfortunately this operation in MSSQL requires the |
315 | C<db_ddladmin> privilege, which is normally not included in the standard |
316 | write-permissions. |
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317 | |
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318 | =head2 Ordered Subselects |
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319 | |
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320 | If you attempted the following query (among many others) in Microsoft SQL |
321 | Server |
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322 | |
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323 | $rs->search ({}, { |
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324 | prefetch => 'relation', |
325 | rows => 2, |
326 | offset => 3, |
327 | }); |
328 | |
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329 | You may be surprised to receive an exception. The reason for this is a quirk |
330 | in the MSSQL engine itself, and sadly doesn't have a sensible workaround due |
331 | to the way DBIC is built. DBIC can do truly wonderful things with the aid of |
332 | subselects, and does so automatically when necessary. The list of situations |
333 | when a subselect is necessary is long and still changes often, so it can not |
334 | be exhaustively enumerated here. The general rule of thumb is a joined |
335 | L<has_many|DBIx::Class::Relationship/has_many> relationship with limit/group |
336 | applied to the left part of the join. |
337 | |
338 | In its "pursuit of standards" Microsft SQL Server goes to great lengths to |
339 | forbid the use of ordered subselects. This breaks a very useful group of |
340 | searches like "Give me things number 4 to 6 (ordered by name), and prefetch |
341 | all their relations, no matter how many". While there is a hack which fools |
342 | the syntax checker, the optimizer may B<still elect to break the subselect>. |
343 | Testing has determined that while such breakage does occur (the test suite |
344 | contains an explicit test which demonstrates the problem), it is relative |
345 | rare. The benefits of ordered subselects are on the other hand too great to be |
346 | outright disabled for MSSQL. |
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347 | |
348 | Thus compromise between usability and perfection is the MSSQL-specific |
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349 | L<resultset attribute|DBIx::Class::ResultSet/ATTRIBUTES> C<unsafe_subselect_ok>. |
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350 | It is deliberately not possible to set this on the Storage level, as the user |
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351 | should inspect (and preferably regression-test) the return of every such |
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352 | ResultSet individually. The example above would work if written like: |
353 | |
354 | $rs->search ({}, { |
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355 | unsafe_subselect_ok => 1, |
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356 | prefetch => 'relation', |
357 | rows => 2, |
358 | offset => 3, |
359 | }); |
6de07ea3 |
360 | |
361 | If it is possible to rewrite the search() in a way that will avoid the need |
362 | for this flag - you are urged to do so. If DBIC internals insist that an |
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363 | ordered subselect is necessary for an operation, and you believe there is a |
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364 | different/better way to get the same result - please file a bugreport. |
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365 | |
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366 | =head1 AUTHOR |
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367 | |
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368 | See L<DBIx::Class/AUTHOR> and L<DBIx::Class/CONTRIBUTORS>. |
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369 | |
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370 | =head1 LICENSE |
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371 | |
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372 | You may distribute this code under the same terms as Perl itself. |
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373 | |
75d07914 |
374 | =cut |