1Data::ObjectDriver::BasUesOebrjeCcotn(t3rpimb)uted PerlDDaotcau:m:eOnbtjaetcitoDnriver::BaseObject(3pm)
2
6 Data::ObjectDriver::BaseObject - base class for modeled objects
7
9 package Ingredient;
10 use base qw( Data::ObjectDriver::BaseObject );
11 __PACKAGE__->install_properties({
13 columns => [ 'ingredient_id', 'recipe_id', 'name', 'quantity' ],
14 datasource => 'ingredient',
15 primary_key => [ 'recipe_id', 'ingredient_id' ],
16 driver => FoodDriver->driver,
17 });
18 __PACKAGE__->has_a(
20 { class => 'Recipe', column => 'recipe_id', }
21 );
22 package main;
24 my ($ingredient) = Ingredient->search({ recipe_id => 4, name => 'rutabaga' });
26 $ingredient->quantity(7);
27 $ingredient->save();
28
30 Data::ObjectDriver::BaseObject provides services to data objects
31 modeled with the Data::ObjectDriver object relational mapper.
32
34 "Class->install_properties(\%params)"
35 Defines all the properties of the specified object class. Generally you
36 should call "install_properties()" in the body of your class
37 definition, so the properties can be set when the class is "use"d or
38 "require"d.
39 Required members of %params are:
41 • "columns"
43 All the columns in the object class. This property is an arrayref.
45 • "datasource"
47 The identifier of the table in which the object class's data are
49 stored. Usually the datasource is simply the table name, but the
50 datasource can be decorated into the table name by the
51 "Data::ObjectDriver::DBD" module if the database requires special
52 formatting of table names.
53 • "driver" or "get_driver"
55 The driver used to perform database operations (lookup, update,
57 etc) for the object class.
58 "driver" is the instance of "Data::ObjectDriver" to use. If your
60 driver requires configuration options not available when the
61 properties are initially set, specify a coderef as "get_driver"
62 instead. It will be called the first time the driver is needed,
63 storing the driver in the class's "driver" property for subsequent
64 calls.
65 The optional members of %params are:
67 • "primary_key"
69 The column or columns used to uniquely identify an instance of the
71 object class. If one column (such as a simple numeric ID)
72 identifies the class, "primary_key" should be a scalar. Otherwise,
73 "primary_key" is an arrayref.
74 • "column_defs"
76 Specifies types for specially typed columns, if any, as a hashref.
78 For example, if a column holds a timestamp, name it in
79 "column_defs" as a "date" for proper handling with some
80 "Data::ObjectDriver::Driver::DBD" database drivers. Columns for
81 which types aren't specified are handled as "char" columns.
82 Known "column_defs" types are:
84 • "blob"
86 A blob of binary data. "Data::ObjectDriver::Driver::DBD::Pg"
88 maps this to "DBI::Pg::PG_BYTEA", "DBD::SQLite" to
89 "DBI::SQL_BLOB" and "DBD::Oracle" to "ORA_BLOB".
90 • "bin_char"
92 A non-blob string of binary data.
94 "Data::ObjectDriver::Driver::DBD::SQLite" maps this to
95 "DBI::SQL_BINARY".
96 Other types may be defined by custom database drivers as needed, so
98 consult their documentation.
99 • "db"
101 The name of the database. When used with
103 "Data::ObjectDriver::Driver::DBI" type object drivers, this name is
104 passed to the "init_db" method when the actual database handle is
105 being created.
106 Custom object drivers may define other properties for your object
108 classes. Consult the documentation of those object drivers for more
109 information.
110 "Class->install_column($col, $def)"
112 Modify the Class definition to declare a new column $col of definition
113 <$def> (see column_defs).
114 "Class->has_a(@definitions)"
116 NOTE: "has_a" is an experimental system, likely to both be buggy and
117 change in future versions.
118 Defines a foreign key reference between two classes, creating accessor
120 methods to retrieve objects both ways across the reference. For each
121 defined reference, two methods are created: one for objects of class
122 "Class" to load the objects they reference, and one for objects of the
123 referenced class to load the set of "Class" objects that reference
124 them.
125 For example, this definition:
127 package Ingredient;
129 __PACKAGE__->has_a(
130 { class => 'Recipe', column => 'recipe_id' },
131 );
132 would create "Ingredient->recipe_obj" and "Recipe->ingredient_objs"
134 instance methods.
135 Each member of @definitions is a hashref containing the parameters for
137 creating one accessor method. The required members of these hashes are:
138 • "class"
140 The class to associate.
142 • "column"
144 The column or columns in this class that identify the primary key
146 of the associated object. As with primary keys, use a single scalar
147 string for a single column or an arrayref for a composite key.
148 The optional members of "has_a()" definitions are:
150 • "method"
152 The name of the accessor method to create.
154 By default, the method name is the concatenated set of column names
156 with each "_id" suffix removed, and the suffix "_obj" appended at
157 the end of the method name. For example, if "column" were
158 "['recipe_id', 'ingredient_id']", the resulting method would be
159 called "recipe_ingredient_obj" by default.
160 • "cached"
162 Whether to keep a reference to the foreign object once it's loaded.
164 Subsequent calls to the accessor method would return that reference
165 immediately.
166 • "parent_method"
168 The name of the reciprocal method created in the referenced class
170 named in "class".
171 By default, that method is named with the lowercased name of the
173 current class with the suffix "_objs". For example, if in your
174 "Ingredient" class you defined a relationship with "Recipe" on the
175 column "recipe_id", this would create a "$recipe->ingredient_objs"
176 method.
177 Note that if you reference one class with multiple sets of fields,
179 you can omit only one parent_method; otherwise the methods would be
180 named the same thing. For instance, if you had a "Friend" class
181 with two references to "User" objects in its "user_id" and
182 "friend_id" columns, one of them would need a "parent_method".
183 "Class->has_partitions(%param)"
185 Defines that the given class is partitioned, configuring it for use
186 with the "Data::ObjectDriver::Driver::SimplePartition" object driver.
187 Required members of %param are:
188 • "number"
190 The number of partitions in which objects of this class may be
192 stored.
193 • "get_driver"
195 A function that returns an object driver, given a partition ID and
197 any extra parameters specified when the class's
198 "Data::ObjectDriver::Driver::SimplePartition" was instantiated.
199 Note that only the parent object for use with the "SimplePartition"
201 driver should use "has_partitions()". See
202 "Data::ObjectDriver::Driver::SimplePartition" for more about
203 partitioning.
204
206 "Class->lookup($id)"
207 Returns the instance of "Class" with the given value for its primary
208 key. If "Class" has a complex primary key (more than one column), $id
209 should be an arrayref specifying the column values in the same order as
210 specified in the "primary_key" property.
211 "Class->search(\%terms, [\%args])"
213 Returns all instances of "Class" that match the values specified in
214 "\%terms", keyed on column names. In list context, "search" returns the
215 objects containing those values. In scalar context, "search" returns an
216 iterator function containing the same set of objects.
217 Your search can be customized with parameters specified in "\%args".
219 Commonly recognized parameters (those implemented by the standard
220 "Data::ObjectDriver" object drivers) are:
221 • "sort"
223 A column by which to order the object results.
225 • "direction"
227 If set to "descend", the results (ordered by the "sort" column) are
229 returned in descending order. Otherwise, results will be in
230 ascending order.
231 • "limit"
233 The number of results to return, at most. You can use this with
235 "offset" to paginate your "search()" results.
236 • "offset"
238 The number of results to skip before the first returned result. Use
240 this with "limit" to paginate your "search()" results.
241 • "fetchonly"
243 A list (arrayref) of columns that should be requested. If
245 specified, only the specified columns of the resulting objects are
246 guaranteed to be set to the correct values.
247 Note that any caching object drivers you use may opt to ignore
249 "fetchonly" instructions, or decline to cache objects queried with
250 "fetchonly".
251 • "for_update"
253 If true, instructs the object driver to indicate the query is a
255 search, but the application may want to update the data after. That
256 is, the generated SQL "SELECT" query will include a "FOR UPDATE"
257 clause.
258 All options are passed to the object driver, so your driver may support
260 additional options.
261 "Class->result(\%terms, [\%args])"
263 Takes the same %terms and %args arguments that search takes, but
264 instead of executing the query immediately, returns a
265 Data::ObjectDriver::ResultSet object representing the set of results.
266 "$obj->exists()"
268 Returns true if $obj already exists in the database.
269 "$obj->save()"
271 Saves $obj to the database, whether it is already there or not. That
272 is, "save()" is functionally:
273 $obj->exists() ? $obj->update() : $obj->insert()
275 "$obj->update()"
277 Saves changes to $obj, an object that already exists in its database.
278 "$obj->insert()"
280 Adds $obj to the database in which it should exist, according to its
281 object driver and configuration.
282 "$obj->remove()"
284 Deletes $obj from its database.
285 "$obj->replace()"
287 Replaces $obj in the database. Does the right thing if the driver knows
288 how to REPLACE object, ala MySQL.
289
291 "Class->new(%columns)"
292 Returns a new object of the given class, initializing its columns with
293 the values in %columns.
294 "$obj->init(%columns)"
296 Initializes $obji by initializing its columns with the values in
297 %columns.
298 Override this method if you must do initial configuration to new
300 instances of $obj's class that are not more appropriate as a
301 "post_load" callback.
302 "Class->properties()"
304 Returns the named object class's properties as a hashref. Note that
305 some of the standard object class properties, such as "primary_key",
306 have more convenient accessors than reading the properties directly.
307 "Class->driver()"
309 Returns the object driver for this class, invoking the class's
310 get_driver function (and caching the result for future calls) if
311 necessary.
312 "Class->get_driver($get_driver_fn)"
314 Sets the function used to find the object driver for Class objects
315 (that is, the "get_driver" property).
316 Note that once "driver()" has been called, the "get_driver" function is
318 not used. Usually you would specify your function as the "get_driver"
319 parameter to "install_properties()".
320 "Class->is_pkless()"
322 Returns whether the given object class has a primary key defined.
323 "Class->is_primary_key($column)"
325 Returns whether the given column is or is part of the primary key for
326 "Class" objects.
327 "$obj->primary_key()"
329 Returns the values of the primary key fields of $obj.
330 "Class->primary_key_tuple()"
332 Returns the names of the primary key fields of "Class" objects.
333 "$obj->is_same($other_obj)"
335 Do a primary key check on $obj and $<other_obj> and returns true only
336 if they are identical.
337 "$obj->object_is_stored()"
339 Returns true if the object hasn't been stored in the database yet.
340 This is particularly useful in triggers where you can then determine if
341 the object is being INSERTED or just UPDATED.
342 "$obj->pk_str()"
344 returns the primary key has a printable string.
345 "$obj->has_primary_key()"
347 Returns whether the given object has values for all of its primary key
348 fields.
349 "$obj->uncache_object()"
351 If you use a Cache driver, returned object will be automatically cached
352 as a result of common retrieve operations. In some rare cases you may
353 want the cache to be cleared explicitly, and this method provides you
354 with a way to do it.
355 "$obj->primary_key_to_terms([$id])"
357 Returns $obj's primary key as a hashref of values keyed on column
358 names, suitable for passing as "search()" terms. If $id is specified,
359 convert that primary key instead of $obj's.
360 "Class->datasource()"
362 Returns the datasource for objects of class "Class". That is, returns
363 the "datasource" property of "Class".
364 "Class->columns_of_type($type)"
366 Returns the list of columns in "Class" objects that hold data of type
367 $type, as an arrayref. Columns are of a certain type when they are set
368 that way in "Class"'s "column_defs" property.
369 "$obj->set_values(\%values)"
371 Sets all the columns of $obj that are members of "\%values" to the
372 values specified there.
373 "$obj->set_values_internal(\%values)"
375 Sets new specified values of $obj, without using any overridden mutator
376 methods of $obj and without marking the changed columns changed.
377 "$obj->clone()"
379 Returns a new object of the same class as $obj containing the same
380 data, except for primary keys, which are set to "undef".
381 "$obj->clone_all()"
383 Returns a new object of the same class as $obj containing the same
384 data, including all key fields.
385 "Class->has_column($column)"
387 Returns whether a column named $column exists in objects of class
388 <Class>.
389 "Class->column_names()"
391 Returns the list of columns in "Class" objects as an arrayref.
392 "$obj->column_values()"
394 Returns the columns and values in the given object as a hashref.
395 "$obj->column($column, [$value])"
397 Returns the value of $obj's column $column. If $value is specified,
398 "column()" sets the first.
399 Note the usual way of accessing and mutating column values is through
401 the named accessors:
402 $obj->column('fred', 'barney'); # possible
404 $obj->fred('barney'); # preferred
405 "$obj->is_changed([$column])"
407 Returns whether any values in $obj have changed. If $column is given,
408 returns specifically whether that column has changed.
409 "$obj->changed_cols_and_pk()"
411 Returns the list of all columns that have changed in $obj since it was
412 last loaded from or saved to the database, as a list.
413 "$obj->changed_cols()"
415 Returns the list of changed columns in $obj as a list, except for any
416 columns in $obj's primary key (even if they have changed).
417 "Class->lookup_multi(\@ids)"
419 Returns a list (arrayref) of objects as specified by their primary
420 keys.
421 "Class->bulk_insert(\@columns, \@data)"
423 Adds the given data, an arrayref of arrayrefs containing column values
424 in the order of column names given in "\@columns", as directly to the
425 database as "Class" records.
426 Note that only some database drivers (for example,
428 "Data::ObjectDriver::Driver::DBD::Pg") implement the bulk insert
429 operation.
430 "$obj->fetch_data()"
432 Returns the current values from $obj as saved in the database, as a
433 hashref.
434 "$obj->refresh()"
436 Resets the values of $obj from the database. Any unsaved modifications
437 to $obj will be lost, and any made meanwhile will be reflected in $obj
438 afterward.
439 "$obj->column_func($column)"
441 Creates an accessor/mutator method for column $column, returning it as
442 a coderef.
443 Override this if you need special behavior in all accessor/mutator
445 methods.
446 "$obj->deflate()"
448 Returns a minimal representation of the object, for use in caches where
449 you might want to preserve space (like memcached). Can also be
450 overridden by subclasses to store the optimal representation of an
451 object in the cache. For example, if you have metadata attached to an
452 object, you might want to store that in the cache, as well.
453 "Class->inflate($deflated)"
455 Inflates the deflated representation of the object $deflated into a
456 proper object in the class Class. That is, undoes the operation
457 "$deflated = $obj->deflate()" by returning a new object equivalent to
458 $obj.
459
461 Introduction
462 When dealing with the methods on this class, the transactions are
463 global, i.e: applied to all drivers. You can still enable transactions
464 per driver if you directly use the driver API.
465 "Class->begin_work"
467 This enable transactions globally for all drivers until the next
468 rollback or commit call on the class.
469 If begin_work is called while a transaction is still active (nested
471 transaction) then the two transactions are merged. So inner
472 transactions are ignored and a warning will be emitted.
473 "Class->rollback"
475 This rollbacks all the transactions since the last begin work, and
476 exits from the active transaction state.
477 "Class->commit"
479 Commits the transactions, and exits from the active transaction state.
480 "Class->txn_debug"
482 Just return the value of the global flag and the current working
483 drivers in a hashref.
484 "Class->txn_active"
486 Returns true if a transaction is already active.
487
489 • "Please specify a valid column for class"
490 One of the class relationships you defined with "has_a()" was
492 missing a "column" member.
493 • "Please define a valid method for column"
495 One of the class relationships you defined with "has_a()" was
497 missing its "method" member and a method name could not be
498 generated, or the class for which you specified the relationship
499 already has a method by that name. Perhaps you specified an
500 additional accessor by the same name for that class.
501 • "keys don't match with primary keys: list"
503 The hashref of values you passed as the ID to
505 "primary_key_to_terms()" was missing or had extra members. Perhaps
506 you used a full "column_values()" hash instead of only including
507 that class's key fields.
508 • "You tried to set inexistent column column name to value data on
510 class name"
511 The hashref you specified to "set_values()" contained keys that are
513 not defined columns for that class of object. Perhaps you invoked
514 it on the wrong class, or did not fully filter members of the hash
515 out before using it.
516 • "Cannot find column 'column' for class 'class'"
518 The column you specified to "column()" does not exist for that
520 class, you attempted to use an automatically generated
521 accessor/mutator for a column that doesn't exist, or attempted to
522 use a column accessor as a class method instead of an instance
523 method. Perhaps you performed your call on the wrong class or
524 variable, or misspelled a method or column name.
525 • "Must specify column"
527 You invoked the "column_func()" method without specifying a column
529 name. Column names are required to create the accessor/mutator
530 function, so it knows what data member of the object to use.
531 • "number (of partitions) is required"
533 You attempted to define partitioning for a class without specifying
535 the number of partitions for that class in the "number" member.
536 Perhaps your logic for determining the number of partitions
537 resulted in "undef" or 0.
538 • "get_driver is required"
540 You attempted to define partitioning for a class without specifying
542 the function to find the object driver for a partition ID as the
543 "get_driver" member.
544
546 There are no known bugs in this module.
547
549 Data::ObjectDriver, Data::ObjectDriver::Driver::DBI,
550 Data::ObjectDriver::Driver::SimplePartition
551
553 Data::ObjectDriver is free software; you may redistribute it and/or
554 modify it under the same terms as Perl itself.
555
557 Except where otherwise noted, Data::ObjectDriver is Copyright 2005-2006
558 Six Apart, cpan@sixapart.com. All rights reserved.
559perl v5.34.0 2021-07-22Data::ObjectDriver::BaseObject(3pm)