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 definition,
37 so the properties can be set when the class is "use"d or "require"d.
38 Required members of %params are:
40 • "columns"
42 All the columns in the object class. This property is an arrayref.
44 • "datasource"
46 The identifier of the table in which the object class's data are
48 stored. Usually the datasource is simply the table name, but the
49 datasource can be decorated into the table name by the
50 "Data::ObjectDriver::DBD" module if the database requires special
51 formatting of table names.
52 • "driver" or "get_driver"
54 The driver used to perform database operations (lookup, update,
56 etc) for the object class.
57 "driver" is the instance of "Data::ObjectDriver" to use. If your
59 driver requires configuration options not available when the
60 properties are initially set, specify a coderef as "get_driver"
61 instead. It will be called the first time the driver is needed,
62 storing the driver in the class's "driver" property for subsequent
63 calls.
64 The optional members of %params are:
66 • "primary_key"
68 The column or columns used to uniquely identify an instance of the
70 object class. If one column (such as a simple numeric ID)
71 identifies the class, "primary_key" should be a scalar. Otherwise,
72 "primary_key" is an arrayref.
73 • "column_defs"
75 Specifies types for specially typed columns, if any, as a hashref.
77 For example, if a column holds a timestamp, name it in
78 "column_defs" as a "date" for proper handling with some
79 "Data::ObjectDriver::Driver::DBD" database drivers. Columns for
80 which types aren't specified are handled as "char" columns.
81 Known "column_defs" types are:
83 • "blob"
85 A blob of binary data. "Data::ObjectDriver::Driver::DBD::Pg"
87 maps this to "DBI::Pg::PG_BYTEA", "DBD::SQLite" to
88 "DBI::SQL_BLOB" and "DBD::Oracle" to "ORA_BLOB".
89 • "bin_char"
91 A non-blob string of binary data.
93 "Data::ObjectDriver::Driver::DBD::SQLite" maps this to
94 "DBI::SQL_BINARY".
95 Other types may be defined by custom database drivers as needed, so
97 consult their documentation.
98 • "db"
100 The name of the database. When used with
102 "Data::ObjectDriver::Driver::DBI" type object drivers, this name is
103 passed to the "init_db" method when the actual database handle is
104 being created.
105 Custom object drivers may define other properties for your object
107 classes. Consult the documentation of those object drivers for more
108 information.
109 "Class->install_column($col, $def)"
111 Modify the Class definition to declare a new column $col of definition
112 <$def> (see column_defs).
113 "Class->has_a(@definitions)"
115 NOTE: "has_a" is an experimental system, likely to both be buggy and
116 change in future versions.
117 Defines a foreign key reference between two classes, creating accessor
119 methods to retrieve objects both ways across the reference. For each
120 defined reference, two methods are created: one for objects of class
121 "Class" to load the objects they reference, and one for objects of the
122 referenced class to load the set of "Class" objects that reference
123 them.
124 For example, this definition:
126 package Ingredient;
128 __PACKAGE__->has_a(
129 { class => 'Recipe', column => 'recipe_id' },
130 );
131 would create "Ingredient->recipe_obj" and "Recipe->ingredient_objs"
133 instance methods.
134 Each member of @definitions is a hashref containing the parameters for
136 creating one accessor method. The required members of these hashes are:
137 • "class"
139 The class to associate.
141 • "column"
143 The column or columns in this class that identify the primary key
145 of the associated object. As with primary keys, use a single scalar
146 string for a single column or an arrayref for a composite key.
147 The optional members of has_a() definitions are:
149 • "method"
151 The name of the accessor method to create.
153 By default, the method name is the concatenated set of column names
155 with each "_id" suffix removed, and the suffix "_obj" appended at
156 the end of the method name. For example, if "column" were
157 "['recipe_id', 'ingredient_id']", the resulting method would be
158 called "recipe_ingredient_obj" by default.
159 • "cached"
161 Whether to keep a reference to the foreign object once it's loaded.
163 Subsequent calls to the accessor method would return that reference
164 immediately.
165 • "parent_method"
167 The name of the reciprocal method created in the referenced class
169 named in "class".
170 By default, that method is named with the lowercased name of the
172 current class with the suffix "_objs". For example, if in your
173 "Ingredient" class you defined a relationship with "Recipe" on the
174 column "recipe_id", this would create a "$recipe->ingredient_objs"
175 method.
176 Note that if you reference one class with multiple sets of fields,
178 you can omit only one parent_method; otherwise the methods would be
179 named the same thing. For instance, if you had a "Friend" class
180 with two references to "User" objects in its "user_id" and
181 "friend_id" columns, one of them would need a "parent_method".
182 "Class->has_partitions(%param)"
184 Defines that the given class is partitioned, configuring it for use
185 with the "Data::ObjectDriver::Driver::SimplePartition" object driver.
186 Required members of %param are:
187 • "number"
189 The number of partitions in which objects of this class may be
191 stored.
192 • "get_driver"
194 A function that returns an object driver, given a partition ID and
196 any extra parameters specified when the class's
197 "Data::ObjectDriver::Driver::SimplePartition" was instantiated.
198 Note that only the parent object for use with the "SimplePartition"
200 driver should use has_partitions(). See
201 "Data::ObjectDriver::Driver::SimplePartition" for more about
202 partitioning.
203
205 "Class->lookup($id)"
206 Returns the instance of "Class" with the given value for its primary
207 key. If "Class" has a complex primary key (more than one column), $id
208 should be an arrayref specifying the column values in the same order as
209 specified in the "primary_key" property.
210 "Class->search(\%terms, [\%args])"
212 Returns all instances of "Class" that match the values specified in
213 "\%terms", keyed on column names. In list context, "search" returns the
214 objects containing those values. In scalar context, "search" returns an
215 iterator function containing the same set of objects.
216 Your search can be customized with parameters specified in "\%args".
218 Commonly recognized parameters (those implemented by the standard
219 "Data::ObjectDriver" object drivers) are:
220 • "sort"
222 A column by which to order the object results.
224 • "direction"
226 If set to "descend", the results (ordered by the "sort" column) are
228 returned in descending order. Otherwise, results will be in
229 ascending order.
230 • "limit"
232 The number of results to return, at most. You can use this with
234 "offset" to paginate your search() results.
235 • "offset"
237 The number of results to skip before the first returned result. Use
239 this with "limit" to paginate your search() results.
240 • "fetchonly"
242 A list (arrayref) of columns that should be requested. If
244 specified, only the specified columns of the resulting objects are
245 guaranteed to be set to the correct values.
246 Note that any caching object drivers you use may opt to ignore
248 "fetchonly" instructions, or decline to cache objects queried with
249 "fetchonly".
250 • "for_update"
252 If true, instructs the object driver to indicate the query is a
254 search, but the application may want to update the data after. That
255 is, the generated SQL "SELECT" query will include a "FOR UPDATE"
256 clause.
257 All options are passed to the object driver, so your driver may support
259 additional options.
260 "Class->result(\%terms, [\%args])"
262 Takes the same %terms and %args arguments that search takes, but
263 instead of executing the query immediately, returns a
264 Data::ObjectDriver::ResultSet object representing the set of results.
265 "$obj->exists()"
267 Returns true if $obj already exists in the database.
268 "$obj->save()"
270 Saves $obj to the database, whether it is already there or not. That
271 is, save() is functionally:
272 $obj->exists() ? $obj->update() : $obj->insert()
274 "$obj->update()"
276 Saves changes to $obj, an object that already exists in its database.
277 "$obj->insert()"
279 Adds $obj to the database in which it should exist, according to its
280 object driver and configuration.
281 "$obj->remove()"
283 Deletes $obj from its database.
284 "$obj->replace()"
286 Replaces $obj in the database. Does the right thing if the driver knows
287 how to REPLACE object, ala MySQL.
288
290 "Class->new(%columns)"
291 Returns a new object of the given class, initializing its columns with
292 the values in %columns.
293 "$obj->init(%columns)"
295 Initializes $obji by initializing its columns with the values in
296 %columns.
297 Override this method if you must do initial configuration to new
299 instances of $obj's class that are not more appropriate as a
300 "post_load" callback.
301 "Class->properties()"
303 Returns the named object class's properties as a hashref. Note that
304 some of the standard object class properties, such as "primary_key",
305 have more convenient accessors than reading the properties directly.
306 "Class->driver()"
308 Returns the object driver for this class, invoking the class's
309 get_driver function (and caching the result for future calls) if
310 necessary.
311 "Class->get_driver($get_driver_fn)"
313 Sets the function used to find the object driver for Class objects
314 (that is, the "get_driver" property).
315 Note that once driver() has been called, the "get_driver" function is
317 not used. Usually you would specify your function as the "get_driver"
318 parameter to install_properties().
319 "Class->is_pkless()"
321 Returns whether the given object class has a primary key defined.
322 "Class->is_primary_key($column)"
324 Returns whether the given column is or is part of the primary key for
325 "Class" objects.
326 "$obj->primary_key()"
328 Returns the values of the primary key fields of $obj.
329 "Class->primary_key_tuple()"
331 Returns the names of the primary key fields of "Class" objects.
332 "$obj->is_same($other_obj)"
334 Do a primary key check on $obj and $<other_obj> and returns true only
335 if they are identical.
336 "$obj->object_is_stored()"
338 Returns true if the object hasn't been stored in the database yet.
339 This is particularly useful in triggers where you can then determine if
340 the object is being INSERTED or just UPDATED.
341 "$obj->pk_str()"
343 returns the primary key has a printable string.
344 "$obj->has_primary_key()"
346 Returns whether the given object has values for all of its primary key
347 fields.
348 "$obj->uncache_object()"
350 If you use a Cache driver, returned object will be automatically cached
351 as a result of common retrieve operations. In some rare cases you may
352 want the cache to be cleared explicitly, and this method provides you
353 with a way to do it.
354 "$obj->primary_key_to_terms([$id])"
356 Returns $obj's primary key as a hashref of values keyed on column
357 names, suitable for passing as search() terms. If $id is specified,
358 convert that primary key instead of $obj's.
359 "Class->datasource()"
361 Returns the datasource for objects of class "Class". That is, returns
362 the "datasource" property of "Class".
363 "Class->columns_of_type($type)"
365 Returns the list of columns in "Class" objects that hold data of type
366 $type, as an arrayref. Columns are of a certain type when they are set
367 that way in "Class"'s "column_defs" property.
368 "$obj->set_values(\%values)"
370 Sets all the columns of $obj that are members of "\%values" to the
371 values specified there.
372 "$obj->set_values_internal(\%values)"
374 Sets new specified values of $obj, without using any overridden mutator
375 methods of $obj and without marking the changed columns changed.
376 "$obj->clone()"
378 Returns a new object of the same class as $obj containing the same
379 data, except for primary keys, which are set to "undef".
380 "$obj->clone_all()"
382 Returns a new object of the same class as $obj containing the same
383 data, including all key fields.
384 "Class->has_column($column)"
386 Returns whether a column named $column exists in objects of class
387 <Class>.
388 "Class->column_names()"
390 Returns the list of columns in "Class" objects as an arrayref.
391 "$obj->column_values()"
393 Returns the columns and values in the given object as a hashref.
394 "$obj->column($column, [$value])"
396 Returns the value of $obj's column $column. If $value is specified,
397 column() sets the first.
398 Note the usual way of accessing and mutating column values is through
400 the named accessors:
401 $obj->column('fred', 'barney'); # possible
403 $obj->fred('barney'); # preferred
404 "$obj->is_changed([$column])"
406 Returns whether any values in $obj have changed. If $column is given,
407 returns specifically whether that column has changed.
408 "$obj->changed_cols_and_pk()"
410 Returns the list of all columns that have changed in $obj since it was
411 last loaded from or saved to the database, as a list.
412 "$obj->changed_cols()"
414 Returns the list of changed columns in $obj as a list, except for any
415 columns in $obj's primary key (even if they have changed).
416 "Class->lookup_multi(\@ids)"
418 Returns a list (arrayref) of objects as specified by their primary
419 keys.
420 "Class->bulk_insert(\@columns, \@data)"
422 Adds the given data, an arrayref of arrayrefs containing column values
423 in the order of column names given in "\@columns", as directly to the
424 database as "Class" records.
425 Note that only some database drivers (for example,
427 "Data::ObjectDriver::Driver::DBD::Pg") implement the bulk insert
428 operation.
429 "$obj->fetch_data()"
431 Returns the current values from $obj as saved in the database, as a
432 hashref.
433 "$obj->refresh()"
435 Resets the values of $obj from the database. Any unsaved modifications
436 to $obj will be lost, and any made meanwhile will be reflected in $obj
437 afterward.
438 "$obj->column_func($column)"
440 Creates an accessor/mutator method for column $column, returning it as
441 a coderef.
442 Override this if you need special behavior in all accessor/mutator
444 methods.
445 "$obj->deflate()"
447 Returns a minimal representation of the object, for use in caches where
448 you might want to preserve space (like memcached). Can also be
449 overridden by subclasses to store the optimal representation of an
450 object in the cache. For example, if you have metadata attached to an
451 object, you might want to store that in the cache, as well.
452 "Class->inflate($deflated)"
454 Inflates the deflated representation of the object $deflated into a
455 proper object in the class Class. That is, undoes the operation
456 "$deflated = $obj->deflate()" by returning a new object equivalent to
457 $obj.
458
460 Introduction
461 When dealing with the methods on this class, the transactions are
462 global, i.e: applied to all drivers. You can still enable transactions
463 per driver if you directly use the driver API.
464 "Class->begin_work"
466 This enable transactions globally for all drivers until the next
467 rollback or commit call on the class.
468 If begin_work is called while a transaction is still active (nested
470 transaction) then the two transactions are merged. So inner
471 transactions are ignored and a warning will be emitted.
472 "Class->rollback"
474 This rollbacks all the transactions since the last begin work, and
475 exits from the active transaction state.
476 "Class->commit"
478 Commits the transactions, and exits from the active transaction state.
479 "Class->txn_debug"
481 Just return the value of the global flag and the current working
482 drivers in a hashref.
483 "Class->txn_active"
485 Returns true if a transaction is already active.
486
488 • "Please specify a valid column for class"
489 One of the class relationships you defined with has_a() was missing
491 a "column" member.
492 • "Please define a valid method for column"
494 One of the class relationships you defined with has_a() was missing
496 its "method" member and a method name could not be generated, or
497 the class for which you specified the relationship already has a
498 method by that name. Perhaps you specified an additional accessor
499 by the same name for that class.
500 • "keys don't match with primary keys: list"
502 The hashref of values you passed as the ID to
504 primary_key_to_terms() was missing or had extra members. Perhaps
505 you used a full column_values() hash instead of only including that
506 class's key fields.
507 • "You tried to set inexistent column column name to value data on
509 class name"
510 The hashref you specified to set_values() contained keys that are
512 not defined columns for that class of object. Perhaps you invoked
513 it on the wrong class, or did not fully filter members of the hash
514 out before using it.
515 • "Cannot find column 'column' for class 'class'"
517 The column you specified to column() does not exist for that class,
519 you attempted to use an automatically generated accessor/mutator
520 for a column that doesn't exist, or attempted to use a column
521 accessor as a class method instead of an instance method. Perhaps
522 you performed your call on the wrong class or variable, or
523 misspelled a method or column name.
524 • "Must specify column"
526 You invoked the column_func() method without specifying a column
528 name. Column names are required to create the accessor/mutator
529 function, so it knows what data member of the object to use.
530 • "number (of partitions) is required"
532 You attempted to define partitioning for a class without specifying
534 the number of partitions for that class in the "number" member.
535 Perhaps your logic for determining the number of partitions
536 resulted in "undef" or 0.
537 • "get_driver is required"
539 You attempted to define partitioning for a class without specifying
541 the function to find the object driver for a partition ID as the
542 "get_driver" member.
543
545 There are no known bugs in this module.
546
548 Data::ObjectDriver, Data::ObjectDriver::Driver::DBI,
549 Data::ObjectDriver::Driver::SimplePartition
550
552 Data::ObjectDriver is free software; you may redistribute it and/or
553 modify it under the same terms as Perl itself.
554
556 Except where otherwise noted, Data::ObjectDriver is Copyright 2005-2006
557 Six Apart, cpan@sixapart.com. All rights reserved.
558perl v5.38.0 2023-07-20Data::ObjectDriver::BaseObject(3pm)