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1 | package DBIx::Class::Storage; |
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2 | |
3 | use strict; |
4 | use warnings; |
5 | |
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6 | use base qw/DBIx::Class/; |
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7 | use mro 'c3'; |
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8 | |
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9 | use DBIx::Class::Exception; |
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10 | use Scalar::Util 'weaken'; |
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11 | use DBIx::Class::Storage::TxnScopeGuard; |
f43ea814 |
12 | use Try::Tiny; |
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13 | use namespace::clean; |
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14 | |
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15 | __PACKAGE__->mk_group_accessors('simple' => qw/debug schema/); |
db29433c |
16 | __PACKAGE__->mk_group_accessors('component_class' => 'cursor_class'); |
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17 | |
18 | __PACKAGE__->cursor_class('DBIx::Class::Cursor'); |
19 | |
20 | sub cursor { shift->cursor_class(@_); } |
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21 | |
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22 | package # Hide from PAUSE |
23 | DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION; |
24 | |
25 | use overload '"' => sub { |
26 | 'DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION' |
27 | }; |
28 | |
29 | sub new { |
30 | my $class = shift; |
31 | my $self = {}; |
32 | return bless $self, $class; |
33 | } |
34 | |
35 | package DBIx::Class::Storage; |
36 | |
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37 | =head1 NAME |
38 | |
39 | DBIx::Class::Storage - Generic Storage Handler |
40 | |
41 | =head1 DESCRIPTION |
42 | |
43 | A base implementation of common Storage methods. For specific |
44 | information about L<DBI>-based storage, see L<DBIx::Class::Storage::DBI>. |
45 | |
46 | =head1 METHODS |
47 | |
48 | =head2 new |
49 | |
50 | Arguments: $schema |
51 | |
52 | Instantiates the Storage object. |
53 | |
54 | =cut |
55 | |
56 | sub new { |
57 | my ($self, $schema) = @_; |
58 | |
59 | $self = ref $self if ref $self; |
60 | |
61 | my $new = {}; |
62 | bless $new, $self; |
63 | |
64 | $new->set_schema($schema); |
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65 | $new->debug(1) |
66 | if $ENV{DBIX_CLASS_STORAGE_DBI_DEBUG} || $ENV{DBIC_TRACE}; |
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67 | |
68 | $new; |
69 | } |
70 | |
71 | =head2 set_schema |
72 | |
73 | Used to reset the schema class or object which owns this |
74 | storage object, such as during L<DBIx::Class::Schema/clone>. |
75 | |
76 | =cut |
77 | |
78 | sub set_schema { |
79 | my ($self, $schema) = @_; |
80 | $self->schema($schema); |
6298a324 |
81 | weaken $self->{schema} if ref $self->{schema}; |
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82 | } |
83 | |
84 | =head2 connected |
85 | |
86 | Returns true if we have an open storage connection, false |
87 | if it is not (yet) open. |
88 | |
89 | =cut |
90 | |
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91 | sub connected { die "Virtual method!" } |
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92 | |
93 | =head2 disconnect |
94 | |
95 | Closes any open storage connection unconditionally. |
96 | |
97 | =cut |
98 | |
99 | sub disconnect { die "Virtual method!" } |
100 | |
101 | =head2 ensure_connected |
102 | |
103 | Initiate a connection to the storage if one isn't already open. |
104 | |
105 | =cut |
106 | |
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107 | sub ensure_connected { die "Virtual method!" } |
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108 | |
109 | =head2 throw_exception |
110 | |
111 | Throws an exception - croaks. |
112 | |
113 | =cut |
114 | |
115 | sub throw_exception { |
116 | my $self = shift; |
117 | |
2a2a7b23 |
118 | if (ref $self and $self->schema) { |
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119 | $self->schema->throw_exception(@_); |
120 | } |
121 | else { |
122 | DBIx::Class::Exception->throw(@_); |
123 | } |
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124 | } |
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125 | |
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126 | =head2 txn_do |
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127 | |
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128 | =over 4 |
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129 | |
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130 | =item Arguments: C<$coderef>, @coderef_args? |
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131 | |
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132 | =item Return Value: The return value of $coderef |
133 | |
134 | =back |
135 | |
136 | Executes C<$coderef> with (optional) arguments C<@coderef_args> atomically, |
137 | returning its result (if any). If an exception is caught, a rollback is issued |
138 | and the exception is rethrown. If the rollback fails, (i.e. throws an |
139 | exception) an exception is thrown that includes a "Rollback failed" message. |
140 | |
141 | For example, |
142 | |
143 | my $author_rs = $schema->resultset('Author')->find(1); |
144 | my @titles = qw/Night Day It/; |
145 | |
146 | my $coderef = sub { |
147 | # If any one of these fails, the entire transaction fails |
148 | $author_rs->create_related('books', { |
149 | title => $_ |
150 | }) foreach (@titles); |
151 | |
152 | return $author->books; |
153 | }; |
154 | |
155 | my $rs; |
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156 | try { |
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157 | $rs = $schema->txn_do($coderef); |
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158 | } catch { |
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159 | my $error = shift; |
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160 | # Transaction failed |
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161 | die "something terrible has happened!" # |
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162 | if ($error =~ /Rollback failed/); # Rollback failed |
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163 | |
164 | deal_with_failed_transaction(); |
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165 | }; |
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166 | |
167 | In a nested transaction (calling txn_do() from within a txn_do() coderef) only |
168 | the outermost transaction will issue a L</txn_commit>, and txn_do() can be |
169 | called in void, scalar and list context and it will behave as expected. |
170 | |
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171 | Please note that all of the code in your coderef, including non-DBIx::Class |
172 | code, is part of a transaction. This transaction may fail out halfway, or |
173 | it may get partially double-executed (in the case that our DB connection |
174 | failed halfway through the transaction, in which case we reconnect and |
175 | restart the txn). Therefore it is best that any side-effects in your coderef |
176 | are idempotent (that is, can be re-executed multiple times and get the |
177 | same result), and that you check up on your side-effects in the case of |
178 | transaction failure. |
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179 | |
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180 | =cut |
181 | |
182 | sub txn_do { |
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183 | my $self = shift; |
184 | my $coderef = shift; |
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185 | |
186 | ref $coderef eq 'CODE' or $self->throw_exception |
187 | ('$coderef must be a CODE reference'); |
188 | |
189 | my (@return_values, $return_value); |
190 | |
191 | $self->txn_begin; # If this throws an exception, no rollback is needed |
192 | |
193 | my $wantarray = wantarray; # Need to save this since the context |
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194 | # inside the try{} block is independent |
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195 | # of the context that called txn_do() |
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196 | my $args = \@_; |
197 | |
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198 | try { |
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199 | |
200 | # Need to differentiate between scalar/list context to allow for |
201 | # returning a list in scalar context to get the size of the list |
202 | if ($wantarray) { |
203 | # list context |
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204 | @return_values = $coderef->(@$args); |
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205 | } elsif (defined $wantarray) { |
206 | # scalar context |
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207 | $return_value = $coderef->(@$args); |
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208 | } else { |
209 | # void context |
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210 | $coderef->(@$args); |
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211 | } |
212 | $self->txn_commit; |
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213 | } |
214 | catch { |
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215 | my $error = shift; |
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216 | |
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217 | try { |
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218 | $self->txn_rollback; |
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219 | } catch { |
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220 | my $exception_class = "DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION"; |
221 | $self->throw_exception($error) # propagate nested rollback |
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222 | if $_ =~ /$exception_class/; |
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223 | |
224 | $self->throw_exception( |
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225 | "Transaction aborted: $error. Rollback failed: $_" |
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226 | ); |
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227 | } |
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228 | $self->throw_exception($error); # txn failed but rollback succeeded |
52b420dd |
229 | }; |
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230 | |
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231 | return wantarray ? @return_values : $return_value; |
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232 | } |
233 | |
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234 | =head2 txn_begin |
235 | |
236 | Starts a transaction. |
237 | |
238 | See the preferred L</txn_do> method, which allows for |
239 | an entire code block to be executed transactionally. |
240 | |
241 | =cut |
242 | |
243 | sub txn_begin { die "Virtual method!" } |
244 | |
245 | =head2 txn_commit |
246 | |
247 | Issues a commit of the current transaction. |
248 | |
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249 | It does I<not> perform an actual storage commit unless there's a DBIx::Class |
250 | transaction currently in effect (i.e. you called L</txn_begin>). |
251 | |
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252 | =cut |
253 | |
254 | sub txn_commit { die "Virtual method!" } |
255 | |
256 | =head2 txn_rollback |
257 | |
258 | Issues a rollback of the current transaction. A nested rollback will |
259 | throw a L<DBIx::Class::Storage::NESTED_ROLLBACK_EXCEPTION> exception, |
260 | which allows the rollback to propagate to the outermost transaction. |
261 | |
262 | =cut |
263 | |
264 | sub txn_rollback { die "Virtual method!" } |
265 | |
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266 | =head2 svp_begin |
267 | |
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268 | Arguments: $savepoint_name? |
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269 | |
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270 | Created a new savepoint using the name provided as argument. If no name |
271 | is provided, a random name will be used. |
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272 | |
273 | =cut |
274 | |
275 | sub svp_begin { die "Virtual method!" } |
276 | |
277 | =head2 svp_release |
278 | |
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279 | Arguments: $savepoint_name? |
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280 | |
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281 | Release the savepoint provided as argument. If none is provided, |
282 | release the savepoint created most recently. This will implicitly |
283 | release all savepoints created after the one explicitly released as well. |
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284 | |
285 | =cut |
286 | |
287 | sub svp_release { die "Virtual method!" } |
288 | |
289 | =head2 svp_rollback |
290 | |
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291 | Arguments: $savepoint_name? |
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292 | |
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293 | Rollback to the savepoint provided as argument. If none is provided, |
294 | rollback to the savepoint created most recently. This will implicitly |
295 | release all savepoints created after the savepoint we rollback to. |
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296 | |
297 | =cut |
298 | |
299 | sub svp_rollback { die "Virtual method!" } |
300 | |
dd018f09 |
301 | =for comment |
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302 | |
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303 | =head2 txn_scope_guard |
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304 | |
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305 | An alternative way of transaction handling based on |
306 | L<DBIx::Class::Storage::TxnScopeGuard>: |
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307 | |
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308 | my $txn_guard = $storage->txn_scope_guard; |
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309 | |
310 | $row->col1("val1"); |
311 | $row->update; |
312 | |
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313 | $txn_guard->commit; |
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314 | |
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315 | If an exception occurs, or the guard object otherwise leaves the scope |
316 | before C<< $txn_guard->commit >> is called, the transaction will be rolled |
317 | back by an explicit L</txn_rollback> call. In essence this is akin to |
318 | using a L</txn_begin>/L</txn_commit> pair, without having to worry |
319 | about calling L</txn_rollback> at the right places. Note that since there |
320 | is no defined code closure, there will be no retries and other magic upon |
321 | database disconnection. If you need such functionality see L</txn_do>. |
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322 | |
323 | =cut |
324 | |
325 | sub txn_scope_guard { |
326 | return DBIx::Class::Storage::TxnScopeGuard->new($_[0]); |
327 | } |
328 | |
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329 | =head2 sql_maker |
330 | |
331 | Returns a C<sql_maker> object - normally an object of class |
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332 | C<DBIx::Class::SQLMaker>. |
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333 | |
334 | =cut |
335 | |
336 | sub sql_maker { die "Virtual method!" } |
337 | |
338 | =head2 debug |
339 | |
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340 | Causes trace information to be emitted on the L</debugobj> object. |
341 | (or C<STDERR> if L</debugobj> has not specifically been set). |
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342 | |
343 | This is the equivalent to setting L</DBIC_TRACE> in your |
344 | shell environment. |
345 | |
346 | =head2 debugfh |
347 | |
348 | Set or retrieve the filehandle used for trace/debug output. This should be |
48580715 |
349 | an IO::Handle compatible object (only the C<print> method is used. Initially |
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350 | set to be STDERR - although see information on the |
351 | L<DBIC_TRACE> environment variable. |
352 | |
353 | =cut |
354 | |
355 | sub debugfh { |
356 | my $self = shift; |
357 | |
358 | if ($self->debugobj->can('debugfh')) { |
359 | return $self->debugobj->debugfh(@_); |
360 | } |
361 | } |
362 | |
363 | =head2 debugobj |
364 | |
365 | Sets or retrieves the object used for metric collection. Defaults to an instance |
366 | of L<DBIx::Class::Storage::Statistics> that is compatible with the original |
367 | method of using a coderef as a callback. See the aforementioned Statistics |
368 | class for more information. |
369 | |
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370 | =cut |
371 | |
372 | sub debugobj { |
373 | my $self = shift; |
374 | |
375 | if (@_) { |
376 | return $self->{debugobj} = $_[0]; |
377 | } |
378 | |
379 | $self->{debugobj} ||= do { |
380 | if (my $profile = $ENV{DBIC_TRACE_PROFILE}) { |
381 | require DBIx::Class::Storage::Debug::PrettyPrint; |
382 | if ($profile =~ /^\.?\//) { |
383 | require Config::Any; |
384 | |
385 | my $cfg = try { |
386 | Config::Any->load_files({ files => [$profile], use_ext => 1 }); |
387 | } catch { |
388 | # sanitize the error message a bit |
389 | $_ =~ s/at \s+ .+ Storage\.pm \s line \s \d+ $//x; |
390 | $self->throw_exception("Failure processing \$ENV{DBIC_TRACE_PROFILE}: $_"); |
391 | }; |
392 | |
393 | DBIx::Class::Storage::Debug::PrettyPrint->new(values %{$cfg->[0]}); |
394 | } |
395 | else { |
396 | DBIx::Class::Storage::Debug::PrettyPrint->new({ profile => $profile }); |
397 | } |
398 | } |
399 | else { |
400 | require DBIx::Class::Storage::Statistics; |
401 | DBIx::Class::Storage::Statistics->new |
402 | } |
403 | }; |
404 | } |
405 | |
046ad905 |
406 | =head2 debugcb |
407 | |
408 | Sets a callback to be executed each time a statement is run; takes a sub |
409 | reference. Callback is executed as $sub->($op, $info) where $op is |
410 | SELECT/INSERT/UPDATE/DELETE and $info is what would normally be printed. |
411 | |
f92a9d79 |
412 | See L</debugobj> for a better way. |
046ad905 |
413 | |
414 | =cut |
415 | |
416 | sub debugcb { |
417 | my $self = shift; |
418 | |
419 | if ($self->debugobj->can('callback')) { |
420 | return $self->debugobj->callback(@_); |
421 | } |
422 | } |
423 | |
e4eb8ee1 |
424 | =head2 cursor_class |
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425 | |
426 | The cursor class for this Storage object. |
427 | |
428 | =cut |
429 | |
046ad905 |
430 | =head2 deploy |
431 | |
432 | Deploy the tables to storage (CREATE TABLE and friends in a SQL-based |
433 | Storage class). This would normally be called through |
434 | L<DBIx::Class::Schema/deploy>. |
435 | |
436 | =cut |
437 | |
438 | sub deploy { die "Virtual method!" } |
439 | |
a3eaff0e |
440 | =head2 connect_info |
441 | |
442 | The arguments of C<connect_info> are always a single array reference, |
443 | and are Storage-handler specific. |
444 | |
445 | This is normally accessed via L<DBIx::Class::Schema/connection>, which |
446 | encapsulates its argument list in an arrayref before calling |
447 | C<connect_info> here. |
448 | |
449 | =cut |
450 | |
046ad905 |
451 | sub connect_info { die "Virtual method!" } |
a3eaff0e |
452 | |
453 | =head2 select |
454 | |
455 | Handle a select statement. |
456 | |
457 | =cut |
458 | |
459 | sub select { die "Virtual method!" } |
460 | |
461 | =head2 insert |
462 | |
463 | Handle an insert statement. |
464 | |
465 | =cut |
466 | |
046ad905 |
467 | sub insert { die "Virtual method!" } |
a3eaff0e |
468 | |
469 | =head2 update |
470 | |
471 | Handle an update statement. |
472 | |
473 | =cut |
474 | |
046ad905 |
475 | sub update { die "Virtual method!" } |
a3eaff0e |
476 | |
477 | =head2 delete |
478 | |
479 | Handle a delete statement. |
480 | |
481 | =cut |
482 | |
046ad905 |
483 | sub delete { die "Virtual method!" } |
a3eaff0e |
484 | |
485 | =head2 select_single |
486 | |
487 | Performs a select, fetch and return of data - handles a single row |
488 | only. |
489 | |
490 | =cut |
491 | |
046ad905 |
492 | sub select_single { die "Virtual method!" } |
a3eaff0e |
493 | |
494 | =head2 columns_info_for |
495 | |
c22c7625 |
496 | Returns metadata for the given source's columns. This |
497 | is *deprecated*, and will be removed before 1.0. You should |
498 | be specifying the metadata yourself if you need it. |
a3eaff0e |
499 | |
500 | =cut |
501 | |
046ad905 |
502 | sub columns_info_for { die "Virtual method!" } |
503 | |
504 | =head1 ENVIRONMENT VARIABLES |
505 | |
506 | =head2 DBIC_TRACE |
507 | |
508 | If C<DBIC_TRACE> is set then trace information |
f92a9d79 |
509 | is produced (as when the L</debug> method is set). |
046ad905 |
510 | |
511 | If the value is of the form C<1=/path/name> then the trace output is |
512 | written to the file C</path/name>. |
513 | |
514 | This environment variable is checked when the storage object is first |
fd323bf1 |
515 | created (when you call connect on your schema). So, run-time changes |
516 | to this environment variable will not take effect unless you also |
046ad905 |
517 | re-connect on your schema. |
518 | |
b6cd6478 |
519 | =head2 DBIC_TRACE_PROFILE |
520 | |
521 | If C<DBIC_TRACE_PROFILE> is set, L<DBIx::Class::Storage::PrettyPrint> |
522 | will be used to format the output from C<DBIC_TRACE>. The value it |
523 | is set to is the C<profile> that it will be used. If the value is a |
524 | filename the file is read with L<Config::Any> and the results are |
525 | used as the configuration for tracing. See L<SQL::Abstract::Tree/new> |
526 | for what that structure should look like. |
527 | |
528 | |
046ad905 |
529 | =head2 DBIX_CLASS_STORAGE_DBI_DEBUG |
530 | |
531 | Old name for DBIC_TRACE |
532 | |
ace385bd |
533 | =head1 SEE ALSO |
534 | |
2f0790c4 |
535 | L<DBIx::Class::Storage::DBI> - reference storage implementation using |
536 | SQL::Abstract and DBI. |
ace385bd |
537 | |
046ad905 |
538 | =head1 AUTHORS |
539 | |
540 | Matt S. Trout <mst@shadowcatsystems.co.uk> |
541 | |
542 | Andy Grundman <andy@hybridized.org> |
543 | |
544 | =head1 LICENSE |
545 | |
546 | You may distribute this code under the same terms as Perl itself. |
547 | |
548 | =cut |
549 | |
a62cf8d4 |
550 | 1; |