DBIx::Class::Row(3pm) User Contributed Perl Documentation DBIx::Class::Row(3pm)
NAME
DBIx::Class::Row - Basic row methods
SYNOPSIS
DESCRIPTION
This class is responsible for defining and doing basic operations on rows derived from DBIx::Class::ResultSource objects.
Row objects are returned from DBIx::Class::ResultSets using the create, find, next and all methods, as well as invocations of 'single' (
belongs_to, has_one or might_have) relationship accessors of DBIx::Class::Row objects.
METHODS
new
my $row = My::Class->new(\%attrs);
my $row = $schema->resultset('MySource')->new(\%colsandvalues);
Arguments: \%attrs or \%colsandvalues
Returns: A Row object
While you can create a new row object by calling "new" directly on this class, you are better off calling it on a DBIx::Class::ResultSet
object.
When calling it directly, you will not get a complete, usable row object until you pass or set the "result_source" attribute, to a
DBIx::Class::ResultSource instance that is attached to a DBIx::Class::Schema with a valid connection.
$attrs is a hashref of column name, value data. It can also contain some other attributes such as the "result_source".
Passing an object, or an arrayref of objects as a value will call "set_from_related" in DBIx::Class::Relationship::Base for you. When
passed a hashref or an arrayref of hashrefs as the value, these will be turned into objects via new_related, and treated as if you had
passed objects.
For a more involved explanation, see "create" in DBIx::Class::ResultSet.
Please note that if a value is not passed to new, no value will be sent in the SQL INSERT call, and the column will therefore assume
whatever default value was specified in your database. While DBIC will retrieve the value of autoincrement columns, it will never make an
explicit database trip to retrieve default values assigned by the RDBMS. You can explicitly request that all values be fetched back from
the database by calling "discard_changes", or you can supply an explicit "undef" to columns with NULL as the default, and save yourself a
SELECT.
CAVEAT:
The behavior described above will backfire if you use a foreign key column
with a database-defined default. If you call the relationship accessor on
an object that doesn't have a set value for the FK column, DBIC will throw
an exception, as it has no way of knowing the PK of the related object (if
there is one).
insert
$row->insert;
Arguments: none
Returns: The Row object
Inserts an object previously created by "new" into the database if it isn't already in there. Returns the object itself. To insert an
entirely new row into the database, use "create" in DBIx::Class::ResultSet.
To fetch an uninserted row object, call new on a resultset.
This will also insert any uninserted, related objects held inside this one, see "create" in DBIx::Class::ResultSet for more details.
in_storage
$row->in_storage; # Get value
$row->in_storage(1); # Set value
Arguments: none or 1|0
Returns: 1|0
Indicates whether the object exists as a row in the database or not. This is set to true when "find" in DBIx::Class::ResultSet, "create" in
DBIx::Class::ResultSet or "insert" in DBIx::Class::ResultSet are used.
Creating a row object using "new" in DBIx::Class::ResultSet, or calling "delete" on one, sets it to false.
update
$row->update(\%columns?)
Arguments: none or a hashref
Returns: The Row object
Throws an exception if the row object is not yet in the database, according to "in_storage".
This method issues an SQL UPDATE query to commit any changes to the object to the database if required (see "get_dirty_columns"). It
throws an exception if a proper WHERE clause uniquely identifying the database row can not be constructed (see significance of primary keys
for more details).
Also takes an optional hashref of "column_name => value" pairs to update on the object first. Be aware that the hashref will be passed to
"set_inflated_columns", which might edit it in place, so don't rely on it being the same after a call to "update". If you need to preserve
the hashref, it is sufficient to pass a shallow copy to "update", e.g. ( { %{ $href } } )
If the values passed or any of the column values set on the object contain scalar references, e.g.:
$row->last_modified('NOW()');
# OR
$row->update({ last_modified => 'NOW()' });
The update will pass the values verbatim into SQL. (See SQL::Abstract docs). The values in your Row object will NOT change as a result of
the update call, if you want the object to be updated with the actual values from the database, call "discard_changes" after the update.
$row->update()->discard_changes();
To determine before calling this method, which column values have changed and will be updated, call "get_dirty_columns".
To check if any columns will be updated, call "is_changed".
To force a column to be updated, call "make_column_dirty" before this method.
delete
$row->delete
Arguments: none
Returns: The Row object
Throws an exception if the object is not in the database according to "in_storage". Also throws an exception if a proper WHERE clause
uniquely identifying the database row can not be constructed (see significance of primary keys for more details).
The object is still perfectly usable, but "in_storage" will now return 0 and the object must be reinserted using "insert" before it can be
used to "update" the row again.
If you delete an object in a class with a "has_many" relationship, an attempt is made to delete all the related objects as well. To turn
this behaviour off, pass "cascade_delete => 0" in the $attr hashref of the relationship, see DBIx::Class::Relationship. Any database-level
cascade or restrict will take precedence over a DBIx-Class-based cascading delete, since DBIx-Class deletes the main row first and only
then attempts to delete any remaining related rows.
If you delete an object within a txn_do() (see "txn_do" in DBIx::Class::Storage) and the transaction subsequently fails, the row object
will remain marked as not being in storage. If you know for a fact that the object is still in storage (i.e. by inspecting the cause of the
transaction's failure), you can use "$obj->in_storage(1)" to restore consistency between the object and the database. This would allow a
subsequent "$obj->delete" to work as expected.
See also "delete" in DBIx::Class::ResultSet.
get_column
my $val = $row->get_column($col);
Arguments: $columnname
Returns: The value of the column
Throws an exception if the column name given doesn't exist according to "has_column".
Returns a raw column value from the row object, if it has already been fetched from the database or set by an accessor.
If an inflated value has been set, it will be deflated and returned.
Note that if you used the "columns" or the "select/as" search attributes on the resultset from which $row was derived, and did not include
$columnname in the list, this method will return "undef" even if the database contains some value.
To retrieve all loaded column values as a hash, use "get_columns".
has_column_loaded
if ( $row->has_column_loaded($col) ) {
print "$col has been loaded from db";
}
Arguments: $columnname
Returns: 0|1
Returns a true value if the column value has been loaded from the database (or set locally).
get_columns
my %data = $row->get_columns;
Arguments: none
Returns: A hash of columnname, value pairs.
Returns all loaded column data as a hash, containing raw values. To get just one value for a particular column, use "get_column".
See "get_inflated_columns" to get the inflated values.
get_dirty_columns
my %data = $row->get_dirty_columns;
Arguments: none
Returns: A hash of column, value pairs
Only returns the column, value pairs for those columns that have been changed on this object since the last "update" or "insert" call.
See "get_columns" to fetch all column/value pairs.
make_column_dirty
$row->make_column_dirty($col)
Arguments: $columnname
Returns: undefined
Throws an exception if the column does not exist.
Marks a column as having been changed regardless of whether it has really changed.
get_inflated_columns
my %inflated_data = $obj->get_inflated_columns;
Arguments: none
Returns: A hash of column, object|value pairs
Returns a hash of all column keys and associated values. Values for any columns set to use inflation will be inflated and returns as
objects.
See "get_columns" to get the uninflated values.
See DBIx::Class::InflateColumn for how to setup inflation.
set_column
$row->set_column($col => $val);
Arguments: $columnname, $value
Returns: $value
Sets a raw column value. If the new value is different from the old one, the column is marked as dirty for when you next call "update".
If passed an object or reference as a value, this method will happily attempt to store it, and a later "insert" or "update" will try and
stringify/numify as appropriate. To set an object to be deflated instead, see "set_inflated_columns".
set_columns
$row->set_columns({ $col => $val, ... });
Arguments: \%columndata
Returns: The Row object
Sets multiple column, raw value pairs at once.
Works as "set_column".
set_inflated_columns
$row->set_inflated_columns({ $col => $val, $relname => $obj, ... });
Arguments: \%columndata
Returns: The Row object
Sets more than one column value at once. Any inflated values are deflated and the raw values stored.
Any related values passed as Row objects, using the relation name as a key, are reduced to the appropriate foreign key values and stored.
If instead of related row objects, a hashref of column, value data is passed, will create the related object first then store.
Will even accept arrayrefs of data as a value to a "has_many" in DBIx::Class::Relationship key, and create the related objects if
necessary.
Be aware that the input hashref might be edited in place, so don't rely on it being the same after a call to "set_inflated_columns". If you
need to preserve the hashref, it is sufficient to pass a shallow copy to "set_inflated_columns", e.g. ( { %{ $href } } )
See also "set_from_related" in DBIx::Class::Relationship::Base.
copy
my $copy = $orig->copy({ change => $to, ... });
Arguments: \%replacementdata
Returns: The Row object copy
Inserts a new row into the database, as a copy of the original object. If a hashref of replacement data is supplied, these will take
precedence over data in the original. Also any columns which have the column info attribute "is_auto_increment => 1" are explicitly removed
before the copy, so that the database can insert its own autoincremented values into the new object.
Relationships will be followed by the copy procedure only if the relationship specifies a true value for its cascade_copy attribute.
"cascade_copy" is set by default on "has_many" relationships and unset on all others.
store_column
$row->store_column($col => $val);
Arguments: $columnname, $value
Returns: The value sent to storage
Set a raw value for a column without marking it as changed. This method is used internally by "set_column" which you should probably be
using.
This is the lowest level at which data is set on a row object, extend this method to catch all data setting methods.
inflate_result
Class->inflate_result($result_source, \%me, \%prefetch?)
Arguments: $result_source, \%columndata, \%prefetcheddata
Returns: A Row object
All DBIx::Class::ResultSet methods that retrieve data from the database and turn it into row objects call this method.
Extend this method in your Result classes to hook into this process, for example to rebless the result into a different class.
Reblessing can also be done more easily by setting "result_class" in your Result class. See "result_class" in DBIx::Class::ResultSource.
Different types of results can also be created from a particular DBIx::Class::ResultSet, see "result_class" in DBIx::Class::ResultSet.
update_or_insert
$row->update_or_insert
Arguments: none
Returns: Result of update or insert operation
"Update"s the object if it's already in the database, according to "in_storage", else "insert"s it.
insert_or_update
$obj->insert_or_update
Alias for "update_or_insert"
is_changed
my @changed_col_names = $row->is_changed();
if ($row->is_changed()) { ... }
Arguments: none
Returns: 0|1 or @columnnames
In list context returns a list of columns with uncommited changes, or in scalar context returns a true value if there are uncommitted
changes.
is_column_changed
if ($row->is_column_changed('col')) { ... }
Arguments: $columname
Returns: 0|1
Returns a true value if the column has uncommitted changes.
result_source
my $resultsource = $row->result_source;
Arguments: $result_source_instance
Returns: a ResultSource instance
Accessor to the DBIx::Class::ResultSource this object was created from.
register_column
$column_info = { .... };
$class->register_column($column_name, $column_info);
Arguments: $columnname, \%columninfo
Returns: undefined
Registers a column on the class. If the column_info has an 'accessor' key, creates an accessor named after the value if defined; if there
is no such key, creates an accessor with the same name as the column
The column_info attributes are described in "add_columns" in DBIx::Class::ResultSource
get_from_storage
my $copy = $row->get_from_storage($attrs)
Arguments: \%attrs
Returns: A Row object
Fetches a fresh copy of the Row object from the database and returns it. 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
primary key ). 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 determine if any changes have been made in the database since it was
created.
To just update your Row object with any latest changes from the database, use "discard_changes" instead.
The \%attrs argument should be compatible with "ATTRIBUTES" in DBIx::Class::ResultSet.
discard_changes ($attrs?)
$row->discard_changes
Arguments: none or $attrs
Returns: self (updates object in-place)
Re-selects the row from the database, losing any changes that had 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 primary key).
This method can also be used to refresh from storage, retrieving any changes made since the row was last read from storage.
$attrs, if supplied, is expected to be a hashref of attributes suitable for passing as the second argument to "$resultset->search($cond,
$attrs)";
Note: If you are using DBIx::Class::Storage::DBI::Replicated as your storage, please kept in mind that if you "discard_changes" on a row
that you just updated or created, you should wrap the entire bit inside a transaction. Otherwise you run the risk that you insert or
update to the master database but read from a replicant database that has not yet been updated from the master. This will result in
unexpected results.
throw_exception
See "throw_exception" in DBIx::Class::Schema.
id
my @pk = $row->id;
Arguments: none
Returns: A list of primary key values
Returns the primary key(s) for a row. Can't be called as a class method. Actually implemented in DBIx::Class::PK
AUTHORS
Matt S. Trout <mst@shadowcatsystems.co.uk>
LICENSE
You may distribute this code under the same terms as Perl itself.
perl v5.14.2 2011-11-29 DBIx::Class::Row(3pm)