Bio::DB::PersistentObjectI - DESCRIPTION of Interface
Give standard usage here
Describe the interface here
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The rest of the documentation details each of the object methods. Internal methods are usually preceded with a _
Create (insert), store (update), remove (delete), and the primary key
Title : create
Usage : $obj->create()
Function: Creates the object as a persistent object in the datastore. This
is equivalent to an insert.
Note that you will be able to retrieve the primary key at any time
by calling primary_key() on the object.
Example :
Returns : The newly assigned primary key.
Args : Optionally, additional named parameters. A common parameter will
be -fkobjs, with a reference to an array of foreign key objects
that are not retrievable from the persistent object itself.
Title : store
Usage : $obj->store()
Function: Updates the persistent object in the datastore to reflect its
attribute values.
Example :
Returns : TRUE on success and FALSE otherwise
Args : Optionally, additional named parameters. A common parameter will
be -fkobjs, with a reference to an array of foreign key objects
that are not retrievable from the persistent object itself.
Title : remove Usage : $obj->remove() Function: Removes the persistent object from the datastore. Example : Returns : TRUE on success and FALSE otherwise Args : none
Title : primary_key
Usage : $obj->primary_key($newval)
Function: Get the primary key of the persistent object in the datastore.
Note that an implementation may not permit changing the
primary key once it has been set. For most applications,
changing an existing primary key value to another one is a
potentially very hazardous operation and will hence be
prohibited.
Example :
Returns : value of primary_key (a scalar)
Args : new value (a scalar, optional)
Title : obj
Usage : $obj->obj()
Function: Get/set the object that is made persistent through this adaptor.
Note that an implementation is not required to allow
setting a value. In fact, an implementation is encouraged
to disallow changing the value once it has been set.
Implementations based on inheriting from the class to be
made persistent will just return $self here.
Example :
Returns : The object made persistent through this adaptor
Args : On set, the new value. Read above for caveat.
Rollback and commit
Title : commit
Usage :
Function: Commits the current transaction, if the underlying driver
supports transactions.
Example :
Returns : TRUE
Args : none
Title : rollback
Usage :
Function: Triggers a rollback of the current transaction, if the
underlying driver supports transactions.
Example :
Returns : TRUE
Args : none
These methods aren't intrinsically necessary on this interface, but rather ease recurrent tasks when serializing objects and translate from object model to relational model.
Title : rank
Usage : $obj->rank($newval)
Function: Get/set the rank of this persistent object in a 1:n or n:n
relationship.
This method is here in order to ease maintaining the order
of objects in an array property or cardinality-n
association. Unless the schema mandates the corresponding
attribute as NOT NULL, derived classes may override the
implementation given here with an empty one.
In practice it may only pertain to few objects and hence
could be just as well stuck onto those classes instead of
also on the interface. This design decision is up for debate -
if people don''t like it, it can be changed without too
much effort.
Example :
Returns : value of rank (a scalar)
Args : new value (a scalar or undef, optional)
Title : foreign_key_slot
Usage : $obj->foreign_key_slot($newval)
Function: Get/set of the slot name that is referring to this persistent
object as a foreign key.
This should come in a fully-qualified form. The fully qualified
form is the class name (or adaptor name for the class) that defines
the slot, followed by a double-colon and the name of the slot
(method) itself. I.e., it is the name of the method as class
method.
Without this method, the name of the foreign key may be determined
automatically based on naming convention, or based on a full
mapping table. Neither is always possible because the situation can
be ambiguous, e.g., if an entity references another instance of
itself as foreign key, or if an entity references the same other
entity via multiple foreign keys (e.g. entity associated to itself).
This method is here only to aid ferrying this value from adaptors
to schema drivers and mappers who need to actually figure the
name of the foreign key column in the physical schema. An adaptor
is not required to use it, and everyone else other than the intended
sender and recipient should know what he/she is doing before
tampering with it.
Example :
Returns : value of foreign_key_slot (a scalar)
Args : new value (a scalar or undef, optional)
