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Data::ObjectDriver::BaUserjContributed Perl DData::ObjectDriver::BaseObject(3)

NAME
       Data::ObjectDriver::BaseObject -	base class for modeled objects

SYNOPSIS
	   package Ingredient;
	   use base qw(	Data::ObjectDriver::BaseObject );

	   __PACKAGE__->install_properties({
	       columns	   => [	'ingredient_id', 'recipe_id', 'name', 'quantity' ],
	       datasource  => 'ingredient',
	       primary_key => [	'recipe_id', 'ingredient_id' ],
	       driver	   => FoodDriver->driver,
	   });

	   __PACKAGE__->has_a(
	       { class => 'Recipe', column => 'recipe_id', }
	   );

	   package main;

	   my ($ingredient) = Ingredient->search({ recipe_id =>	4, name	=> 'rutabaga' });
	   $ingredient->quantity(7);
	   $ingredient->save();

DESCRIPTION
       Data::ObjectDriver::BaseObject provides services	to data	objects
       modeled with the	Data::ObjectDriver object relational mapper.

CLASS DEFINITION
   "Class->install_properties(\%params)"
       Defines all the properties of the specified object class. Generally you
       should call "install_properties()" in the body of your class
       definition, so the properties can be set	when the class is "use"d or
       "require"d.

       Required	members	of %params are:

       o   "columns"

	   All the columns in the object class.	This property is an arrayref.

       o   "datasource"

	   The identifier of the table in which	the object class's data	are
	   stored.  Usually the	datasource is simply the table name, but the
	   datasource can be decorated into the	table name by the
	   "Data::ObjectDriver::DBD" module if the database requires special
	   formatting of table names.

       o   "driver" or "get_driver"

	   The driver used to perform database operations (lookup, update,
	   etc)	for the	object class.

	   "driver" is the instance of "Data::ObjectDriver" to use. If your
	   driver requires configuration options not available when the
	   properties are initially set, specify a coderef as "get_driver"
	   instead. It will be called the first	time the driver	is needed,
	   storing the driver in the class's "driver" property for subsequent
	   calls.

       The optional members of %params are:

       o   "primary_key"

	   The column or columns used to uniquely identify an instance of the
	   object class. If one	column (such as	a simple numeric ID)
	   identifies the class, "primary_key" should be a scalar. Otherwise,
	   "primary_key" is an arrayref.

       o   "column_defs"

	   Specifies types for specially typed columns,	if any,	as a hashref.
	   For example,	if a column holds a timestamp, name it in
	   "column_defs" as a "date" for proper	handling with some
	   "Data::ObjectDriver::Driver::DBD" database drivers.	Columns	for
	   which types aren't specified	are handled as "char" columns.

	   Known "column_defs" types are:

	   o   "blob"

	       A blob of binary	data. "Data::ObjectDriver::Driver::DBD::Pg"
	       maps this to "DBI::Pg::PG_BYTEA", "DBD::SQLite" to
	       "DBI::SQL_BLOB" and "DBD::Oracle" to "ORA_BLOB".

	   o   "bin_char"

	       A non-blob string of binary data.
	       "Data::ObjectDriver::Driver::DBD::SQLite" maps this to
	       "DBI::SQL_BINARY".

	   Other types may be defined by custom	database drivers as needed, so
	   consult their documentation.

       o   "db"

	   The name of the database. When used with
	   "Data::ObjectDriver::Driver::DBI" type object drivers, this name is
	   passed to the "init_db" method when the actual database handle is
	   being created.

       Custom object drivers may define	other properties for your object
       classes.	 Consult the documentation of those object drivers for more
       information.

   "Class->install_column($col,	$def)"
       Modify the Class	definition to declare a	new column $col	of definition
       <$def> (see column_defs).

   "Class->has_a(@definitions)"
       NOTE: "has_a" is	an experimental	system,	likely to both be buggy	and
       change in future	versions.

       Defines a foreign key reference between two classes, creating accessor
       methods to retrieve objects both	ways across the	reference. For each
       defined reference, two methods are created: one for objects of class
       "Class" to load the objects they	reference, and one for objects of the
       referenced class	to load	the set	of "Class" objects that	reference
       them.

       For example, this definition:

	   package Ingredient;
	   __PACKAGE__->has_a(
	       { class => 'Recipe', column => 'recipe_id' },
	   );

       would create "Ingredient->recipe_obj" and "Recipe->ingredient_objs"
       instance	methods.

       Each member of @definitions is a	hashref	containing the parameters for
       creating	one accessor method. The required members of these hashes are:

       o   "class"

	   The class to	associate.

       o   "column"

	   The column or columns in this class that identify the primary key
	   of the associated object. As	with primary keys, use a single	scalar
	   string for a	single column or an arrayref for a composite key.

       The optional members of "has_a()" definitions are:

       o   "method"

	   The name of the accessor method to create.

	   By default, the method name is the concatenated set of column names
	   with	each "_id" suffix removed, and the suffix "_obj" appended at
	   the end of the method name. For example, if "column"	were
	   "['recipe_id', 'ingredient_id']", the resulting method would	be
	   called "recipe_ingredient_obj" by default.

       o   "cached"

	   Whether to keep a reference to the foreign object once it's loaded.
	   Subsequent calls to the accessor method would return	that reference
	   immediately.

       o   "parent_method"

	   The name of the reciprocal method created in	the referenced class
	   named in "class".

	   By default, that method is named with the lowercased	name of	the
	   current class with the suffix "_objs". For example, if in your
	   "Ingredient"	class you defined a relationship with "Recipe" on the
	   column "recipe_id", this would create a "$recipe->ingredient_objs"
	   method.

	   Note	that if	you reference one class	with multiple sets of fields,
	   you can omit	only one parent_method;	otherwise the methods would be
	   named the same thing.  For instance,	if you had a "Friend" class
	   with	two references to "User" objects in its	"user_id" and
	   "friend_id" columns,	one of them would need a "parent_method".

   "Class->has_partitions(%param)"
       Defines that the	given class is partitioned, configuring	it for use
       with the	"Data::ObjectDriver::Driver::SimplePartition" object driver.
       Required	members	of %param are:

       o   "number"

	   The number of partitions in which objects of	this class may be
	   stored.

       o   "get_driver"

	   A function that returns an object driver, given a partition ID and
	   any extra parameters	specified when the class's
	   "Data::ObjectDriver::Driver::SimplePartition" was instantiated.

       Note that only the parent object	for use	with the "SimplePartition"
       driver should use "has_partitions()". See
       "Data::ObjectDriver::Driver::SimplePartition" for more about
       partitioning.

BASIC USAGE
   "Class->lookup($id)"
       Returns the instance of "Class" with the	given value for	its primary
       key. If "Class" has a complex primary key (more than one	column), $id
       should be an arrayref specifying	the column values in the same order as
       specified in the	"primary_key" property.

   "Class->search(\%terms, [\%args])"
       Returns all instances of	"Class"	that match the values specified	in
       "\%terms", keyed	on column names. In list context, "search" returns the
       objects containing those	values.	In scalar context, "search" returns an
       iterator	function containing the	same set of objects.

       Your search can be customized with parameters specified in "\%args".
       Commonly	recognized parameters (those implemented by the	standard
       "Data::ObjectDriver" object drivers) are:

       o   "sort"

	   A column by which to	order the object results.

       o   "direction"

	   If set to "descend",	the results (ordered by	the "sort" column) are
	   returned in descending order. Otherwise, results will be in
	   ascending order.

       o   "limit"

	   The number of results to return, at most. You can use this with
	   "offset" to paginate	your "search()"	results.

       o   "offset"

	   The number of results to skip before	the first returned result. Use
	   this	with "limit" to	paginate your "search()" results.

       o   "fetchonly"

	   A list (arrayref) of	columns	that should be requested. If
	   specified, only the specified columns of the	resulting objects are
	   guaranteed to be set	to the correct values.

	   Note	that any caching object	drivers	you use	may opt	to ignore
	   "fetchonly" instructions, or	decline	to cache objects queried with
	   "fetchonly".

       o   "for_update"

	   If true, instructs the object driver	to indicate the	query is a
	   search, but the application may want	to update the data after. That
	   is, the generated SQL "SELECT" query	will include a "FOR UPDATE"
	   clause.

       All options are passed to the object driver, so your driver may support
       additional options.

   "Class->result(\%terms, [\%args])"
       Takes the same %terms and %args arguments that search takes, but
       instead of executing the	query immediately, returns a
       Data::ObjectDriver::ResultSet object representing the set of results.

   "$obj->exists()"
       Returns true if $obj already exists in the database.

   "$obj->save()"
       Saves $obj to the database, whether it is already there or not. That
       is, "save()" is functionally:

	   $obj->exists() ? $obj->update() : $obj->insert()

   "$obj->update()"
       Saves changes to	$obj, an object	that already exists in its database.

   "$obj->insert()"
       Adds $obj to the	database in which it should exist, according to	its
       object driver and configuration.

   "$obj->remove()"
       Deletes $obj from its database.

   "$obj->replace()"
       Replaces	$obj in	the database. Does the right thing if the driver knows
       how to REPLACE object, ala MySQL.

USAGE
   "Class->new(%columns)"
       Returns a new object of the given class,	initializing its columns with
       the values in %columns.

   "$obj->init(%columns)"
       Initializes $obji by initializing its columns with the values in
       %columns.

       Override	this method if you must	do initial configuration to new
       instances of $obj's class that are not more appropriate as a
       "post_load" callback.

   "Class->properties()"
       Returns the named object	class's	properties as a	hashref. Note that
       some of the standard object class properties, such as "primary_key",
       have more convenient accessors than reading the properties directly.

   "Class->driver()"
       Returns the object driver for this class, invoking the class's
       get_driver function (and	caching	the result for future calls) if
       necessary.

   "Class->get_driver($get_driver_fn)"
       Sets the	function used to find the object driver	for Class objects
       (that is, the "get_driver" property).

       Note that once "driver()" has been called, the "get_driver" function is
       not used. Usually you would specify your	function as the	"get_driver"
       parameter to "install_properties()".

   "Class->is_pkless()"
       Returns whether the given object	class has a primary key	defined.

   "Class->is_primary_key($column)"
       Returns whether the given column	is or is part of the primary key for
       "Class" objects.

   "$obj->primary_key()"
       Returns the values of the primary key fields of $obj.

   "Class->primary_key_tuple()"
       Returns the names of the	primary	key fields of "Class" objects.

   "$obj->is_same($other_obj)"
       Do a primary key	check on $obj and $<other_obj> and returns true	only
       if they are identical.

   "$obj->object_is_stored()"
       Returns true if the object hasn't been stored in	the database yet.
       This is particularly useful in triggers where you can then determine if
       the object is being INSERTED or just UPDATED.

   "$obj->pk_str()"
       returns the primary key has a printable string.

   "$obj->has_primary_key()"
       Returns whether the given object	has values for all of its primary key
       fields.

   "$obj->uncache_object()"
       If you use a Cache driver, returned object will be automatically	cached
       as a result of common retrieve operations. In some rare cases you may
       want the	cache to be cleared explicitly,	and this method	provides you
       with a way to do	it.

   "$obj->primary_key_to_terms([$id])"
       Returns $obj's primary key as a hashref of values keyed on column
       names, suitable for passing as "search()" terms.	If $id is specified,
       convert that primary key	instead	of $obj's.

   "Class->datasource()"
       Returns the datasource for objects of class "Class". That is, returns
       the "datasource"	property of "Class".

   "Class->columns_of_type($type)"
       Returns the list	of columns in "Class" objects that hold	data of	type
       $type, as an arrayref. Columns are of a certain type when they are set
       that way	in "Class"'s "column_defs" property.

   "$obj->set_values(\%values)"
       Sets all	the columns of $obj that are members of	"\%values" to the
       values specified	there.

   "$obj->set_values_internal(\%values)"
       Sets new	specified values of $obj, without using	any overridden mutator
       methods of $obj and without marking the changed columns changed.

   "$obj->clone()"
       Returns a new object of the same	class as $obj containing the same
       data, except for	primary	keys, which are	set to "undef".

   "$obj->clone_all()"
       Returns a new object of the same	class as $obj containing the same
       data, including all key fields.

   "Class->has_column($column)"
       Returns whether a column	named $column exists in	objects	of class
       <Class>.

   "Class->column_names()"
       Returns the list	of columns in "Class" objects as an arrayref.

   "$obj->column_values()"
       Returns the columns and values in the given object as a hashref.

   "$obj->column($column, [$value])"
       Returns the value of $obj's column $column. If $value is	specified,
       "column()" sets the first.

       Note the	usual way of accessing and mutating column values is through
       the named accessors:

	   $obj->column('fred',	'barney');  # possible
	   $obj->fred('barney');	    # preferred

   "$obj->is_changed([$column])"
       Returns whether any values in $obj have changed.	If $column is given,
       returns specifically whether that column	has changed.

   "$obj->changed_cols_and_pk()"
       Returns the list	of all columns that have changed in $obj since it was
       last loaded from	or saved to the	database, as a list.

   "$obj->changed_cols()"
       Returns the list	of changed columns in $obj as a	list, except for any
       columns in $obj's primary key (even if they have	changed).

   "Class->lookup_multi(\@ids)"
       Returns a list (arrayref) of objects as specified by their primary
       keys.

   "Class->bulk_insert(\@columns, \@data)"
       Adds the	given data, an arrayref	of arrayrefs containing	column values
       in the order of column names given in "\@columns", as directly to the
       database	as "Class" records.

       Note that only some database drivers (for example,
       "Data::ObjectDriver::Driver::DBD::Pg") implement	the bulk insert
       operation.

   "$obj->fetch_data()"
       Returns the current values from $obj as saved in	the database, as a
       hashref.

   "$obj->refresh()"
       Resets the values of $obj from the database. Any	unsaved	modifications
       to $obj will be lost, and any made meanwhile will be reflected in $obj
       afterward.

   "$obj->column_func($column)"
       Creates an accessor/mutator method for column $column, returning	it as
       a coderef.

       Override	this if	you need special behavior in all accessor/mutator
       methods.

   "$obj->deflate()"
       Returns a minimal representation	of the object, for use in caches where
       you might want to preserve space	(like memcached). Can also be
       overridden by subclasses	to store the optimal representation of an
       object in the cache. For	example, if you	have metadata attached to an
       object, you might want to store that in the cache, as well.

   "Class->inflate($deflated)"
       Inflates	the deflated representation of the object $deflated into a
       proper object in	the class Class. That is, undoes the operation
       "$deflated = $obj->deflate()" by	returning a new	object equivalent to
       $obj.

TRANSACTION SUPPORT AND	METHODS
   Introduction
       When dealing with the methods on	this class, the	transactions are
       global, i.e: applied to all drivers. You	can still enable transactions
       per driver if you directly use the driver API.

   "Class->begin_work"
       This enable transactions	globally for all drivers until the next
       rollback	or commit call on the class.

       If begin_work is	called while a transaction is still active (nested
       transaction) then the two transactions are merged. So inner
       transactions are	ignored	and a warning will be emitted.

   "Class->rollback"
       This rollbacks all the transactions since the last begin	work, and
       exits from the active transaction state.

   "Class->commit"
       Commits the transactions, and exits from	the active transaction state.

   "Class->txn_debug"
       Just return the value of	the global flag	and the	current	working
       drivers in a hashref.

   "Class->txn_active"
       Returns true if a transaction is	already	active.

DIAGNOSTICS
       o   "Please specify a valid column for class"

	   One of the class relationships you defined with "has_a()" was
	   missing a "column" member.

       o   "Please define a valid method for column"

	   One of the class relationships you defined with "has_a()" was
	   missing its "method"	member and a method name could not be
	   generated, or the class for which you specified the relationship
	   already has a method	by that	name. Perhaps you specified an
	   additional accessor by the same name	for that class.

       o   "keys don't match with primary keys:	list"

	   The hashref of values you passed as the ID to
	   "primary_key_to_terms()" was	missing	or had extra members. Perhaps
	   you used a full "column_values()" hash instead of only including
	   that	class's	key fields.

       o   "You	tried to set inexistent	column column name to value data on
	   class name"

	   The hashref you specified to	"set_values()" contained keys that are
	   not defined columns for that	class of object. Perhaps you invoked
	   it on the wrong class, or did not fully filter members of the hash
	   out before using it.

       o   "Cannot find	column 'column'	for class 'class'"

	   The column you specified to "column()" does not exist for that
	   class, you attempted	to use an automatically	generated
	   accessor/mutator for	a column that doesn't exist, or	attempted to
	   use a column	accessor as a class method instead of an instance
	   method. Perhaps you performed your call on the wrong	class or
	   variable, or	misspelled a method or column name.

       o   "Must specify column"

	   You invoked the "column_func()" method without specifying a column
	   name.  Column names are required to create the accessor/mutator
	   function, so	it knows what data member of the object	to use.

       o   "number (of partitions) is required"

	   You attempted to define partitioning	for a class without specifying
	   the number of partitions for	that class in the "number" member.
	   Perhaps your	logic for determining the number of partitions
	   resulted in "undef" or 0.

       o   "get_driver is required"

	   You attempted to define partitioning	for a class without specifying
	   the function	to find	the object driver for a	partition ID as	the
	   "get_driver"	member.

BUGS AND LIMITATIONS
       There are no known bugs in this module.

SEE ALSO
       Data::ObjectDriver, Data::ObjectDriver::Driver::DBI,
       Data::ObjectDriver::Driver::SimplePartition

LICENSE
       Data::ObjectDriver is free software; you	may redistribute it and/or
       modify it under the same	terms as Perl itself.

AUTHOR & COPYRIGHT
       Except where otherwise noted, Data::ObjectDriver	is Copyright 2005-2006
       Six Apart, cpan@sixapart.com. All rights	reserved.

perl v5.32.0			  2020-03-03 Data::ObjectDriver::BaseObject(3)

NAME | SYNOPSIS | DESCRIPTION | CLASS DEFINITION | BASIC USAGE | USAGE | TRANSACTION SUPPORT AND METHODS | DIAGNOSTICS | BUGS AND LIMITATIONS | SEE ALSO | LICENSE | AUTHOR & COPYRIGHT

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