according to L</in_storage>.
This method issues an SQL UPDATE query to commit any changes to the
-object to the database if required.
+object to the database if required (see L</get_dirty_columns>).
+It throws an exception if a proper WHERE clause uniquely identifying
+the database row can not be constructed (see
+L<significance of primary keys|DBIx::Class::Manual::Intro/The Significance and Importance of Primary Keys>
+for more details).
Also takes an optional hashref of C<< column_name => value> >> pairs
to update on the object first. Be aware that the hashref will be
=back
Throws an exception if the object is not in the database according to
-L</in_storage>. Runs an SQL DELETE statement using the primary key
-values to locate the row.
+L</in_storage>. Also throws an exception if a proper WHERE clause
+uniquely identifying the database row can not be constructed (see
+L<significance of primary keys|DBIx::Class::Manual::Intro/The Significance and Importance of Primary Keys>
+for more details).
The object is still perfectly usable, but L</in_storage> will
now return 0 and the object must be reinserted using L</insert>
=back
Fetches a fresh copy of the Row object from the database and returns it.
-
-If passed the \%attrs argument, will first apply these attributes to
+Throws an exception if a proper WHERE clause identifying the database row
+can not be constructed (i.e. if the original object does not contain its
+entire
+ L<primary key|DBIx::Class::Manual::Intro/The Significance and Importance of Primary Keys>
+). If passed the \%attrs argument, will first apply these attributes to
the resultset used to find the row.
This copy can then be used to compare to an existing row object, to
=head2 discard_changes ($attrs)
Re-selects the row from the database, losing any changes that had
-been made.
+been made. Throws an exception if a proper WHERE clause identifying
+the database row can not be constructed (i.e. if the original object
+does not contain its entire
+L<primary key|DBIx::Class::Manual::Intro/The Significance and Importance of Primary Keys>
+).
This method can also be used to refresh from storage, retrieving any
changes made since the row was last read from storage.