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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'; |
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11 | |
d3a2e424 |
12 | use Try::Tiny; |
13 | use DBIx::Class::_Util qw( dbic_internal_try sigwarn_silencer ); |
fd323bf1 |
14 | use namespace::clean; |
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15 | |
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16 | __PACKAGE__->mk_group_accessors(simple => qw/ |
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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 | |
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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, $args) = @_; |
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33 | |
34 | # cast MONEY values properly |
35 | if ($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) { |
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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) = $self->next::method (@_); |
54 | |
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55 | # SELECT SCOPE_IDENTITY only works within a statement scope. We |
4a0eed52 |
56 | # must try to always use this particular idiom first, as it is the |
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57 | # only one that guarantees retrieving the correct id under high |
58 | # concurrency. When this fails we will fall back to whatever secondary |
59 | # retrieval method is specified in _identity_method, but at this |
60 | # point we don't have many guarantees we will get what we expected. |
61 | # http://msdn.microsoft.com/en-us/library/ms190315.aspx |
62 | # http://davidhayden.com/blog/dave/archive/2006/01/17/2736.aspx |
25d3127d |
63 | if ($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) { |
ddcc02d1 |
84 | ($identity) = dbic_internal_try { $sth->fetchrow_array }; |
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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) : $rv; |
7b1b2582 |
99 | } |
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100 | |
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101 | sub last_insert_id { shift->_identity } |
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102 | |
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103 | # |
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104 | # MSSQL is retarded wrt ordered subselects. One needs to add a TOP |
6a247f33 |
105 | # to *all* subqueries, but one also *can't* use TOP 100 PERCENT |
e74c68ce |
106 | # http://sqladvice.com/forums/permalink/18496/22931/ShowThread.aspx#22931 |
f0bd60fc |
107 | # |
108 | sub _select_args_to_query { |
b928a9d5 |
109 | #my ($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 | ) { |
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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 | |
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128 | $sql_bind; |
f0bd60fc |
129 | } |
130 | |
131 | |
4c0f4206 |
132 | # savepoint syntax is the same as in Sybase ASE |
133 | |
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134 | sub _exec_svp_begin { |
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135 | my ($self, $name) = @_; |
136 | |
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137 | $self->_dbh->do("SAVE TRANSACTION $name"); |
4c0f4206 |
138 | } |
139 | |
140 | # A new SAVE TRANSACTION with the same name releases the previous one. |
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141 | sub _exec_svp_release { 1 } |
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142 | |
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143 | sub _exec_svp_rollback { |
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144 | my ($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 | |
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154 | my $supports_rno = 0; |
ff153e24 |
155 | |
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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. |
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164 | dbic_internal_try { |
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165 | $self->_get_dbh->selectrow_array('SELECT row_number() OVER (ORDER BY rand())'); |
166 | $supports_rno = 1; |
167 | }; |
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168 | } |
e76e7b5c |
169 | |
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170 | return $supports_rno ? 'RowNumberOver' : 'Top'; |
ed8de058 |
171 | } |
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172 | |
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173 | sub _ping { |
174 | my $self = shift; |
175 | |
176 | my $dbh = $self->_dbh or return 0; |
177 | |
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178 | dbic_internal_try { |
179 | local $dbh->{RaiseError} = 1; |
180 | local $dbh->{PrintError} = 0; |
ecdf1ac8 |
181 | |
ecdf1ac8 |
182 | $dbh->do('select 1'); |
52b420dd |
183 | 1; |
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184 | } |
185 | catch { |
186 | # MSSQL is *really* annoying wrt multiple active resultsets, |
187 | # and this may very well be the reason why the _ping failed |
188 | # |
189 | # Proactively disconnect, while hiding annoying warnings if the case |
190 | # |
191 | # The callchain is: |
192 | # < check basic retryability prerequisites (e.g. no txn) > |
193 | # ->retry_handler |
194 | # ->storage->connected() |
195 | # ->ping |
196 | # So if we got here with the in_handler bit set - we won't break |
197 | # anything by a disconnect |
198 | if( $self->{_in_do_block_retry_handler} ) { |
199 | local $SIG{__WARN__} = sigwarn_silencer qr/disconnect invalidates .+? active statement/; |
200 | $self->disconnect; |
201 | } |
202 | |
203 | # RV of _ping itself |
204 | 0; |
205 | }; |
ecdf1ac8 |
206 | } |
207 | |
fb95dc4d |
208 | package # hide from PAUSE |
209 | DBIx::Class::Storage::DBI::MSSQL::DateTime::Format; |
210 | |
fd323bf1 |
211 | my $datetime_format = '%Y-%m-%d %H:%M:%S.%3N'; # %F %T |
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212 | my $smalldatetime_format = '%Y-%m-%d %H:%M:%S'; |
213 | |
214 | my ($datetime_parser, $smalldatetime_parser); |
215 | |
216 | sub parse_datetime { |
217 | shift; |
218 | require DateTime::Format::Strptime; |
219 | $datetime_parser ||= DateTime::Format::Strptime->new( |
220 | pattern => $datetime_format, |
221 | on_error => 'croak', |
222 | ); |
223 | return $datetime_parser->parse_datetime(shift); |
224 | } |
225 | |
226 | sub format_datetime { |
227 | shift; |
228 | require DateTime::Format::Strptime; |
229 | $datetime_parser ||= DateTime::Format::Strptime->new( |
230 | pattern => $datetime_format, |
231 | on_error => 'croak', |
232 | ); |
233 | return $datetime_parser->format_datetime(shift); |
234 | } |
235 | |
236 | sub parse_smalldatetime { |
237 | shift; |
238 | require DateTime::Format::Strptime; |
239 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
240 | pattern => $smalldatetime_format, |
241 | on_error => 'croak', |
242 | ); |
243 | return $smalldatetime_parser->parse_datetime(shift); |
244 | } |
245 | |
246 | sub format_smalldatetime { |
247 | shift; |
248 | require DateTime::Format::Strptime; |
249 | $smalldatetime_parser ||= DateTime::Format::Strptime->new( |
250 | pattern => $smalldatetime_format, |
251 | on_error => 'croak', |
252 | ); |
253 | return $smalldatetime_parser->format_datetime(shift); |
254 | } |
255 | |
75d07914 |
256 | 1; |
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257 | |
75d07914 |
258 | =head1 NAME |
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259 | |
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260 | DBIx::Class::Storage::DBI::MSSQL - Base Class for Microsoft SQL Server support |
261 | in DBIx::Class |
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262 | |
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263 | =head1 SYNOPSIS |
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264 | |
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265 | This is the base class for Microsoft SQL Server support, used by |
266 | L<DBIx::Class::Storage::DBI::ODBC::Microsoft_SQL_Server> and |
267 | L<DBIx::Class::Storage::DBI::Sybase::Microsoft_SQL_Server>. |
eb0323df |
268 | |
5a77aa8b |
269 | =head1 IMPLEMENTATION NOTES |
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270 | |
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271 | =head2 IDENTITY information |
272 | |
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273 | Microsoft SQL Server supports three methods of retrieving the IDENTITY |
274 | value for inserted row: IDENT_CURRENT, @@IDENTITY, and SCOPE_IDENTITY(). |
275 | SCOPE_IDENTITY is used here because it is the safest. However, it must |
276 | be called is the same execute statement, not just the same connection. |
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277 | |
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278 | So, this implementation appends a SELECT SCOPE_IDENTITY() statement |
279 | onto each INSERT to accommodate that requirement. |
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280 | |
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281 | C<SELECT @@IDENTITY> can also be used by issuing: |
282 | |
283 | $self->_identity_method('@@identity'); |
284 | |
08cdc412 |
285 | it will only be used if SCOPE_IDENTITY() fails. |
286 | |
287 | This is more dangerous, as inserting into a table with an on insert trigger that |
288 | inserts into another table with an identity will give erroneous results on |
289 | recent versions of SQL Server. |
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290 | |
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291 | =head2 identity insert |
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292 | |
293 | Be aware that we have tried to make things as simple as possible for our users. |
c84189e1 |
294 | For MSSQL that means that when a user tries to create a row, while supplying an |
295 | explicit value for an autoincrementing column, we will try to issue the |
296 | appropriate database call to make this possible, namely C<SET IDENTITY_INSERT |
297 | $table_name ON>. Unfortunately this operation in MSSQL requires the |
298 | C<db_ddladmin> privilege, which is normally not included in the standard |
299 | write-permissions. |
fd05d10a |
300 | |
d74f2da9 |
301 | =head2 Ordered Subselects |
6de07ea3 |
302 | |
d74f2da9 |
303 | If you attempted the following query (among many others) in Microsoft SQL |
304 | Server |
6de07ea3 |
305 | |
6de07ea3 |
306 | $rs->search ({}, { |
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307 | prefetch => 'relation', |
308 | rows => 2, |
309 | offset => 3, |
310 | }); |
311 | |
d74f2da9 |
312 | You may be surprised to receive an exception. The reason for this is a quirk |
313 | in the MSSQL engine itself, and sadly doesn't have a sensible workaround due |
314 | to the way DBIC is built. DBIC can do truly wonderful things with the aid of |
315 | subselects, and does so automatically when necessary. The list of situations |
316 | when a subselect is necessary is long and still changes often, so it can not |
317 | be exhaustively enumerated here. The general rule of thumb is a joined |
318 | L<has_many|DBIx::Class::Relationship/has_many> relationship with limit/group |
319 | applied to the left part of the join. |
320 | |
321 | In its "pursuit of standards" Microsft SQL Server goes to great lengths to |
322 | forbid the use of ordered subselects. This breaks a very useful group of |
323 | searches like "Give me things number 4 to 6 (ordered by name), and prefetch |
324 | all their relations, no matter how many". While there is a hack which fools |
325 | the syntax checker, the optimizer may B<still elect to break the subselect>. |
326 | Testing has determined that while such breakage does occur (the test suite |
327 | contains an explicit test which demonstrates the problem), it is relative |
328 | rare. The benefits of ordered subselects are on the other hand too great to be |
329 | outright disabled for MSSQL. |
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330 | |
331 | Thus compromise between usability and perfection is the MSSQL-specific |
69a8b315 |
332 | L<resultset attribute|DBIx::Class::ResultSet/ATTRIBUTES> C<unsafe_subselect_ok>. |
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333 | It is deliberately not possible to set this on the Storage level, as the user |
48580715 |
334 | should inspect (and preferably regression-test) the return of every such |
d74f2da9 |
335 | ResultSet individually. The example above would work if written like: |
336 | |
337 | $rs->search ({}, { |
69a8b315 |
338 | unsafe_subselect_ok => 1, |
d74f2da9 |
339 | prefetch => 'relation', |
340 | rows => 2, |
341 | offset => 3, |
342 | }); |
6de07ea3 |
343 | |
344 | If it is possible to rewrite the search() in a way that will avoid the need |
345 | for this flag - you are urged to do so. If DBIC internals insist that an |
d74f2da9 |
346 | ordered subselect is necessary for an operation, and you believe there is a |
48580715 |
347 | different/better way to get the same result - please file a bugreport. |
6de07ea3 |
348 | |
a2bd3796 |
349 | =head1 FURTHER QUESTIONS? |
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350 | |
a2bd3796 |
351 | Check the list of L<additional DBIC resources|DBIx::Class/GETTING HELP/SUPPORT>. |
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352 | |
a2bd3796 |
353 | =head1 COPYRIGHT AND LICENSE |
3885cff6 |
354 | |
a2bd3796 |
355 | This module is free software L<copyright|DBIx::Class/COPYRIGHT AND LICENSE> |
356 | by the L<DBIx::Class (DBIC) authors|DBIx::Class/AUTHORS>. You can |
357 | redistribute it and/or modify it under the same terms as the |
358 | L<DBIx::Class library|DBIx::Class/COPYRIGHT AND LICENSE>. |