Bitrix Framework

Setting value is performed in the familiar manner:

$book = \Bitrix\Main\Test\Typography\BookTable::getByPrimary(1)
	->fetchObject();

$book->setTitle("New title");

The object memorizes its original values. From this moment, the current value can be accessed via the main "getter" get and the database original/actual value can be accessed via auxiliary "getter" method remindActual:

$book->getTitle(); // current value
$book->remindActualTitle(); // actual database value

Primary key can be set only in new objects, you cannot update it in existing objects. When it's needed, you have to create a new object and delete the old one. Also, Bitrix\Main\ORM\Fields\ExpressionField fields cannot be set due to values being calculated automatically and cannot be modified from outside.

To cancel the new value and rollback to the old one, you can use the auxiliary "setter" method reset:

$book = \Bitrix\Main\Test\Typography\BookTable::getByPrimary(1)
	->fetchObject();

echo $book->getTitle();
// prints "Title 1"

$book->setTitle("New title");

echo $book->getTitle();
// prints "New title"

$book->resetTitle();

echo $book->getTitle();
// prints "Title 1"

One more auxiliary "setter" method unset deletes object as if it wasn't retrieved from the database and wasn't set at all:

$book = \Bitrix\Main\Test\Typography\BookTable::getByPrimary(1)
	->fetchObject();

echo $book->getTitle();
// prints "Title 1"

$book->unsetTitle();

echo $book->getTitle();
// null

"Setter" methods also have universal variants for calling with field title as an argument:

$fieldName = 'TITLE';

$book->set($fieldName, "New title");
$book->reset($fieldName);
$book->unset($fieldName);