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Manual Reference Pages  -  DBIX::CLASS::ROW (3)

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NAME

DBIx::Class::Row - Basic row methods

CONTENTS

SYNOPSIS

DESCRIPTION

This class is responsible for defining and doing basic operations on rows derived from DBIx::Class::ResultSource objects.

Result 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 Result objects.

NOTE

All Row objects derived from a Schema-attached DBIx::Class::ResultSet object (such as a typical search-> next call) are actually Result instances, based on your application’s Result Class.

DBIx::Class::Row implements most of the row-based communication with the underlying storage, but a Result class <B>should not inherit from it directlyB>. Usually, Result classes inherit from DBIx::Class::Core, which in turn combines the methods from several classes, one of them being DBIx::Class::Row. Therefore, while many of the methods available to a DBIx::Class::Core-derived Result class are described in the following documentation, it does not detail all of the methods available to Result objects. Refer to DBIx::Class::Manual::ResultClass for more info.

METHODS

    new



  my $result = My::Class->new(\%attrs);

  my $result = $schema->resultset(MySource)->new(\%colsandvalues);



Arguments: \%attrs or \%colsandvalues
Return Value: $result
While you can create a new result 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 doesnt 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).



CW$column_accessor



  # Each pair does the same thing

  # (un-inflated, regular column)
  my $val = $result->get_column(first_name);
  my $val = $result->first_name;

  $result->set_column(first_name => $val);
  $result->first_name($val);

  # (inflated column via DBIx::Class::InflateColumn::DateTime)
  my $val = $result->get_inflated_column(last_modified);
  my $val = $result->last_modified;

  $result->set_inflated_column(last_modified => $val);
  $result->last_modified($val);



Arguments: $value?
Return Value: $value
A column accessor method is created for each column, which is used for getting/setting the value for that column.

The actual method name is based on the accessor name given during the Result Class column definition . Like set_column, this will not store the data in the database until insert or update is called on the row.

    insert



  $result->insert;



Arguments: none
Return Value: $result
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 result object, call new_result 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



  $result->in_storage; # Get value
  $result->in_storage(1); # Set value



Arguments: none or 1|0
Return Value: 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::Row are invoked.

Creating a result object using new_result in DBIx::Class::ResultSet, or calling delete on one, sets it to false.

    update



  $result->update(\%columns?)



Arguments: none or a hashref
Return Value: $result
Throws an exception if the result object is not yet in the database, according to in_storage. Returns the object itself.

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.:



  $result->last_modified(\NOW())->update();
  # OR
  $result->update({ last_modified => \NOW() });



The update will pass the values verbatim into SQL. (See SQL::Abstract docs). The values in your Result 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.



  $result->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



  $result->delete



Arguments: none
Return Value: $result
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 <B>deletes the main row firstB> 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 result 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 = $result->get_column($col);



Arguments: $columnname
Return Value: 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 result 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 $result was derived, and <B>did not includeB> $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 ( $result->has_column_loaded($col) ) {
     print "$col has been loaded from db";
  }



Arguments: $columnname
Return Value: 0|1
Returns a true value if the column value has been loaded from the database (or set locally).

    get_columns



  my %data = $result->get_columns;



Arguments: none
Return Value: 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 = $result->get_dirty_columns;



Arguments: none
Return Value: 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



  $result->make_column_dirty($col)



Arguments: $columnname
Return Value: not defined
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
Return Value: 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



  $result->set_column($col => $val);



Arguments: $columnname, $value
Return Value: $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, or better yet, use $column_accessor.

    set_columns



  $result->set_columns({ $col => $val, ... });



Arguments: \%columndata
Return Value: $result
Sets multiple column, raw value pairs at once.

Works as set_column.

    set_inflated_columns



  $result->set_inflated_columns({ $col => $val, $rel_name => $obj, ... });



Arguments: \%columndata
Return Value: $result
Sets more than one column value at once. Any inflated values are deflated and the raw values stored.

Any related values passed as Result objects, using the relation name as a key, are reduced to the appropriate foreign key values and stored. If instead of related result 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
Return Value: $result 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 <B>onlyB> 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



  $result->store_column($col => $val);



Arguments: $columnname, $value
Return Value: 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 result object, extend this method to catch all data setting methods.

    inflate_result



  Class->inflate_result($result_source, \%me, \%prefetch?)



Arguments: $result_source, \%columndata, \%prefetcheddata
Return Value: $result
All DBIx::Class::ResultSet methods that retrieve data from the database and turn it into result 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



  $result->update_or_insert



Arguments: none
Return Value: Result of update or insert operation
updates the object if it’s already in the database, according to in_storage, else inserts it.

    insert_or_update



  $obj->insert_or_update



Alias for update_or_insert

    is_changed



  my @changed_col_names = $result->is_changed();
  if ($result->is_changed()) { ... }



Arguments: none
Return Value: 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 ($result->is_column_changed(col)) { ... }



Arguments: $columname
Return Value: 0|1
Returns a true value if the column has uncommitted changes.

    result_source



  my $resultsource = $result->result_source;



Arguments: $result_source?
Return Value: $result_source
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
Return Value: not defined
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 = $result->get_from_storage($attrs)



Arguments: \%attrs
Return Value: A Result object
Fetches a fresh copy of the Result 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 result object, to determine if any changes have been made in the database since it was created.

To just update your Result 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



  $result->discard_changes



Arguments: none or $attrs
Return Value: 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, a default of { force_pool => master }
is automatically set for you. Prior to DBIx::Class 0.08109 (before 2010) one would have been required to explicitly wrap the entire operation in a transaction to guarantee that up-to-date results are read from the master database.

    throw_exception

See throw_exception in DBIx::Class::Schema.

    id



  my @pk = $result->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

FURTHER QUESTIONS?

Check the list of additional DBIC resources.

COPYRIGHT AND LICENSE

This module is free software copyright by the DBIx::Class (DBIC) authors. You can redistribute it and/or modify it under the same terms as the DBIx::Class library.
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perl v5.20.3 DBIX::CLASS::ROW (3) 2016-02-11

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