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1 | package DBIx::Class::Storage::DBI::MSSQL; |
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2 | |
75d07914 |
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'; |
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11 | |
e2741c7f |
12 | use DBIx::Class::_Util qw( dbic_internal_try dbic_internal_catch sigwarn_silencer ); |
fd323bf1 |
13 | use namespace::clean; |
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14 | |
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15 | __PACKAGE__->mk_group_accessors(simple => qw/ |
25d3127d |
16 | _identity _identity_method _no_scope_identity_query |
7b1b2582 |
17 | /); |
18 | |
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19 | __PACKAGE__->sql_maker_class('DBIx::Class::SQLMaker::MSSQL'); |
ac93965c |
20 | |
2b8cc2f2 |
21 | __PACKAGE__->sql_quote_char([qw/[ ]/]); |
22 | |
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23 | __PACKAGE__->datetime_parser_type ( |
24 | 'DBIx::Class::Storage::DBI::MSSQL::DateTime::Format' |
25 | ); |
26 | |
40d8d018 |
27 | __PACKAGE__->new_guid('NEWID()'); |
28 | |
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29 | sub _prep_for_execute { |
30 | my $self = shift; |
0e773352 |
31 | my ($op, $ident, $args) = @_; |
5a77aa8b |
32 | |
33 | # cast MONEY values properly |
34 | if ($op eq 'insert' || $op eq 'update') { |
35 | my $fields = $args->[0]; |
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36 | |
52416317 |
37 | my $colinfo = $ident->columns_info([keys %$fields]); |
38 | |
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39 | for my $col (keys %$fields) { |
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40 | # $ident is a result source object with INSERT/UPDATE ops |
52416317 |
41 | if ( |
42 | $colinfo->{$col}{data_type} |
43 | && |
44 | $colinfo->{$col}{data_type} =~ /^money\z/i |
45 | ) { |
5a77aa8b |
46 | my $val = $fields->{$col}; |
47 | $fields->{$col} = \['CAST(? AS MONEY)', [ $col => $val ]]; |
48 | } |
49 | } |
50 | } |
51 | |
52 | my ($sql, $bind) = $self->next::method (@_); |
53 | |
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54 | # SELECT SCOPE_IDENTITY only works within a statement scope. We |
4a0eed52 |
55 | # must try to always use this particular idiom first, as it is the |
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56 | # only one that guarantees retrieving the correct id under high |
57 | # concurrency. When this fails we will fall back to whatever secondary |
58 | # retrieval method is specified in _identity_method, but at this |
59 | # point we don't have many guarantees we will get what we expected. |
60 | # http://msdn.microsoft.com/en-us/library/ms190315.aspx |
61 | # http://davidhayden.com/blog/dave/archive/2006/01/17/2736.aspx |
25d3127d |
62 | if ($self->_perform_autoinc_retrieval and not $self->_no_scope_identity_query) { |
384b8bce |
63 | $sql .= "\nSELECT SCOPE_IDENTITY()"; |
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64 | } |
65 | |
66 | return ($sql, $bind); |
67 | } |
68 | |
69 | sub _execute { |
70 | my $self = shift; |
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71 | |
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72 | # always list ctx - we need the $sth |
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73 | my ($rv, $sth, @bind) = $self->next::method(@_); |
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74 | |
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75 | if ($self->_perform_autoinc_retrieval) { |
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76 | |
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77 | # attempt to bring back the result of SELECT SCOPE_IDENTITY() we tacked |
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78 | # on in _prep_for_execute above |
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79 | my $identity; |
80 | |
81 | # we didn't even try on ftds |
82 | unless ($self->_no_scope_identity_query) { |
ddcc02d1 |
83 | ($identity) = dbic_internal_try { $sth->fetchrow_array }; |
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84 | $sth->finish; |
85 | } |
ed8de058 |
86 | |
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87 | # SCOPE_IDENTITY failed, but we can do something else |
88 | if ( (! $identity) && $self->_identity_method) { |
89 | ($identity) = $self->_dbh->selectrow_array( |
90 | 'select ' . $self->_identity_method |
91 | ); |
92 | } |
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93 | |
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94 | $self->_identity($identity); |
7b1b2582 |
95 | } |
96 | |
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97 | return wantarray ? ($rv, $sth, @bind) : $rv; |
7b1b2582 |
98 | } |
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99 | |
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100 | sub last_insert_id { shift->_identity } |
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101 | |
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102 | # |
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103 | # MSSQL is retarded wrt ordered subselects. One needs to add a TOP |
6a247f33 |
104 | # to *all* subqueries, but one also *can't* use TOP 100 PERCENT |
e74c68ce |
105 | # http://sqladvice.com/forums/permalink/18496/22931/ShowThread.aspx#22931 |
f0bd60fc |
106 | # |
107 | sub _select_args_to_query { |
b928a9d5 |
108 | #my ($self, $ident, $select, $cond, $attrs) = @_; |
f0bd60fc |
109 | my $self = shift; |
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110 | my $attrs = $_[3]; |
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111 | |
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112 | my $sql_bind = $self->next::method (@_); |
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113 | |
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114 | # see if this is an ordered subquery |
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115 | if ( |
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116 | $$sql_bind->[0] !~ /^ \s* \( \s* SELECT \s+ TOP \s+ \d+ \s+ /xi |
117 | and |
bac358c9 |
118 | scalar $self->_extract_order_criteria ($attrs->{order_by}) |
aca481d8 |
119 | ) { |
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120 | $self->throw_exception( |
e705f529 |
121 | 'An ordered subselect encountered - this is not safe! Please see "Ordered Subselects" in DBIx::Class::Storage::DBI::MSSQL' |
122 | ) unless $attrs->{unsafe_subselect_ok}; |
b928a9d5 |
123 | |
124 | $$sql_bind->[0] =~ s/^ \s* \( \s* SELECT (?=\s) / '(SELECT TOP ' . $self->sql_maker->__max_int /exi; |
f0bd60fc |
125 | } |
126 | |
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127 | $sql_bind; |
f0bd60fc |
128 | } |
129 | |
130 | |
4c0f4206 |
131 | # savepoint syntax is the same as in Sybase ASE |
132 | |
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133 | sub _exec_svp_begin { |
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134 | my ($self, $name) = @_; |
135 | |
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136 | $self->_dbh->do("SAVE TRANSACTION $name"); |
4c0f4206 |
137 | } |
138 | |
139 | # A new SAVE TRANSACTION with the same name releases the previous one. |
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140 | sub _exec_svp_release { 1 } |
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141 | |
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142 | sub _exec_svp_rollback { |
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143 | my ($self, $name) = @_; |
144 | |
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145 | $self->_dbh->do("ROLLBACK TRANSACTION $name"); |
4c0f4206 |
146 | } |
147 | |
eb0323df |
148 | sub sqlt_type { 'SQLServer' } |
149 | |
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150 | sub sql_limit_dialect { |
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151 | my $self = shift; |
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152 | |
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153 | my $supports_rno = 0; |
ff153e24 |
154 | |
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155 | if (exists $self->_server_info->{normalized_dbms_version}) { |
156 | $supports_rno = 1 if $self->_server_info->{normalized_dbms_version} >= 9; |
157 | } |
158 | else { |
159 | # User is connecting via DBD::Sybase and has no permission to run |
160 | # stored procedures like xp_msver, or version detection failed for some |
161 | # other reason. |
162 | # So, we use a query to check if RNO is implemented. |
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163 | dbic_internal_try { |
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164 | $self->_get_dbh->selectrow_array('SELECT row_number() OVER (ORDER BY rand())'); |
165 | $supports_rno = 1; |
166 | }; |
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167 | } |
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168 | |
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169 | return $supports_rno ? 'RowNumberOver' : 'Top'; |
ed8de058 |
170 | } |
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171 | |
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172 | sub _ping { |
173 | my $self = shift; |
174 | |
175 | my $dbh = $self->_dbh or return 0; |
176 | |
d3a2e424 |
177 | dbic_internal_try { |
178 | local $dbh->{RaiseError} = 1; |
179 | local $dbh->{PrintError} = 0; |
ecdf1ac8 |
180 | |
ecdf1ac8 |
181 | $dbh->do('select 1'); |
52b420dd |
182 | 1; |
d3a2e424 |
183 | } |
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184 | dbic_internal_catch { |
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185 | # MSSQL is *really* annoying wrt multiple active resultsets, |
186 | # and this may very well be the reason why the _ping failed |
187 | # |
188 | # Proactively disconnect, while hiding annoying warnings if the case |
189 | # |
190 | # The callchain is: |
191 | # < check basic retryability prerequisites (e.g. no txn) > |
192 | # ->retry_handler |
193 | # ->storage->connected() |
194 | # ->ping |
195 | # So if we got here with the in_handler bit set - we won't break |
196 | # anything by a disconnect |
197 | if( $self->{_in_do_block_retry_handler} ) { |
198 | local $SIG{__WARN__} = sigwarn_silencer qr/disconnect invalidates .+? active statement/; |
199 | $self->disconnect; |
200 | } |
201 | |
202 | # RV of _ping itself |
203 | 0; |
204 | }; |
ecdf1ac8 |
205 | } |
206 | |
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207 | package # hide from PAUSE |
208 | DBIx::Class::Storage::DBI::MSSQL::DateTime::Format; |
209 | |
fd323bf1 |
210 | my $datetime_format = '%Y-%m-%d %H:%M:%S.%3N'; # %F %T |
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211 | my $smalldatetime_format = '%Y-%m-%d %H:%M:%S'; |
212 | |
213 | my ($datetime_parser, $smalldatetime_parser); |
214 | |
215 | sub parse_datetime { |
216 | shift; |
217 | require DateTime::Format::Strptime; |
218 | $datetime_parser ||= DateTime::Format::Strptime->new( |
219 | pattern => $datetime_format, |
220 | on_error => 'croak', |
221 | ); |
222 | return $datetime_parser->parse_datetime(shift); |
223 | } |
224 | |
225 | sub format_datetime { |
226 | shift; |
227 | require DateTime::Format::Strptime; |
228 | $datetime_parser ||= DateTime::Format::Strptime->new( |
229 | pattern => $datetime_format, |
230 | on_error => 'croak', |
231 | ); |
232 | return $datetime_parser->format_datetime(shift); |
233 | } |
234 | |
235 | sub parse_smalldatetime { |
236 | shift; |
237 | require DateTime::Format::Strptime; |
238 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
239 | pattern => $smalldatetime_format, |
240 | on_error => 'croak', |
241 | ); |
242 | return $smalldatetime_parser->parse_datetime(shift); |
243 | } |
244 | |
245 | sub format_smalldatetime { |
246 | shift; |
247 | require DateTime::Format::Strptime; |
248 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
249 | pattern => $smalldatetime_format, |
250 | on_error => 'croak', |
251 | ); |
252 | return $smalldatetime_parser->format_datetime(shift); |
253 | } |
254 | |
75d07914 |
255 | 1; |
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256 | |
75d07914 |
257 | =head1 NAME |
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258 | |
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259 | DBIx::Class::Storage::DBI::MSSQL - Base Class for Microsoft SQL Server support |
260 | in DBIx::Class |
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261 | |
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262 | =head1 SYNOPSIS |
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263 | |
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264 | This is the base class for Microsoft SQL Server support, used by |
265 | L<DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server> and |
266 | L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>. |
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267 | |
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268 | =head1 IMPLEMENTATION NOTES |
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269 | |
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270 | =head2 IDENTITY information |
271 | |
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272 | Microsoft SQL Server supports three methods of retrieving the IDENTITY |
273 | value for inserted row: IDENT_CURRENT, @@IDENTITY, and SCOPE_IDENTITY(). |
274 | SCOPE_IDENTITY is used here because it is the safest. However, it must |
275 | be called is the same execute statement, not just the same connection. |
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276 | |
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277 | So, this implementation appends a SELECT SCOPE_IDENTITY() statement |
278 | onto each INSERT to accommodate that requirement. |
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279 | |
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280 | C<SELECT @@IDENTITY> can also be used by issuing: |
281 | |
282 | $self->_identity_method('@@identity'); |
283 | |
08cdc412 |
284 | it will only be used if SCOPE_IDENTITY() fails. |
285 | |
286 | This is more dangerous, as inserting into a table with an on insert trigger that |
287 | inserts into another table with an identity will give erroneous results on |
288 | recent versions of SQL Server. |
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289 | |
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290 | =head2 identity insert |
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291 | |
292 | Be aware that we have tried to make things as simple as possible for our users. |
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293 | For MSSQL that means that when a user tries to create a row, while supplying an |
294 | explicit value for an autoincrementing column, we will try to issue the |
295 | appropriate database call to make this possible, namely C<SET IDENTITY_INSERT |
296 | $table_name ON>. Unfortunately this operation in MSSQL requires the |
297 | C<db_ddladmin> privilege, which is normally not included in the standard |
298 | write-permissions. |
fd05d10a |
299 | |
d74f2da9 |
300 | =head2 Ordered Subselects |
6de07ea3 |
301 | |
d74f2da9 |
302 | If you attempted the following query (among many others) in Microsoft SQL |
303 | Server |
6de07ea3 |
304 | |
6de07ea3 |
305 | $rs->search ({}, { |
6de07ea3 |
306 | prefetch => 'relation', |
307 | rows => 2, |
308 | offset => 3, |
309 | }); |
310 | |
d74f2da9 |
311 | You may be surprised to receive an exception. The reason for this is a quirk |
312 | in the MSSQL engine itself, and sadly doesn't have a sensible workaround due |
313 | to the way DBIC is built. DBIC can do truly wonderful things with the aid of |
314 | subselects, and does so automatically when necessary. The list of situations |
315 | when a subselect is necessary is long and still changes often, so it can not |
316 | be exhaustively enumerated here. The general rule of thumb is a joined |
317 | L<has_many|DBIx::Class::Relationship/has_many> relationship with limit/group |
318 | applied to the left part of the join. |
319 | |
320 | In its "pursuit of standards" Microsft SQL Server goes to great lengths to |
321 | forbid the use of ordered subselects. This breaks a very useful group of |
322 | searches like "Give me things number 4 to 6 (ordered by name), and prefetch |
323 | all their relations, no matter how many". While there is a hack which fools |
324 | the syntax checker, the optimizer may B<still elect to break the subselect>. |
325 | Testing has determined that while such breakage does occur (the test suite |
326 | contains an explicit test which demonstrates the problem), it is relative |
327 | rare. The benefits of ordered subselects are on the other hand too great to be |
328 | outright disabled for MSSQL. |
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329 | |
330 | Thus compromise between usability and perfection is the MSSQL-specific |
69a8b315 |
331 | L<resultset attribute|DBIx::Class::ResultSet/ATTRIBUTES> C<unsafe_subselect_ok>. |
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332 | It is deliberately not possible to set this on the Storage level, as the user |
48580715 |
333 | should inspect (and preferably regression-test) the return of every such |
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334 | ResultSet individually. The example above would work if written like: |
335 | |
336 | $rs->search ({}, { |
69a8b315 |
337 | unsafe_subselect_ok => 1, |
d74f2da9 |
338 | prefetch => 'relation', |
339 | rows => 2, |
340 | offset => 3, |
341 | }); |
6de07ea3 |
342 | |
343 | If it is possible to rewrite the search() in a way that will avoid the need |
344 | for this flag - you are urged to do so. If DBIC internals insist that an |
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345 | ordered subselect is necessary for an operation, and you believe there is a |
48580715 |
346 | different/better way to get the same result - please file a bugreport. |
6de07ea3 |
347 | |
a2bd3796 |
348 | =head1 FURTHER QUESTIONS? |
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349 | |
a2bd3796 |
350 | Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>. |
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351 | |
a2bd3796 |
352 | =head1 COPYRIGHT AND LICENSE |
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353 | |
a2bd3796 |
354 | This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE> |
355 | by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can |
356 | redistribute it and/or modify it under the same terms as the |
357 | L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>. |