# Update object The Update object action updates the object class properties of objects in a data source. ## Usage This action node is used to update properties on one or more objects in a data source. To update many objects at once (a batch update) there are two possible methods: 1. Use a [While](https://docs.appfarm.io/library/action-nodes/while) or [Foreach](https://docs.appfarm.io/library/action-nodes/foreach) action node to iterate over the objects. Add an Update object action node inside the iterator action node with the same data source selected and `Object in context` as the **Selection**. 2. Use only the Update object action node. This method is more performant. See the example *Batch updat*e in the Examples section below. When Update object operates on an object it becomes the [object in context](https://docs.appfarm.io/reference/platform-concepts/objects#object-in-context). This object in context contains the original values prior to the update and these can be accessed using [data bindings](https://docs.appfarm.io/reference/platform-concepts/data-bindings) and [functions](https://docs.appfarm.io/reference/platform-concepts/functions). In addition, the values set in the update are available as *self-properties.* Self-properties are only available in [functions](https://docs.appfarm.io/reference/platform-concepts/functions). These can be used to update properties that are dependent on the values of other properties that are being updated in the same operation. In other words, a function must be used to access to new value of a property, if that property is updated in the same Update Object operations. See the example *Update Object - Self Properties and dependencies* below. ### Examples {% tabs %} {% tab title="A simple update" %} In this example, 1 object is updated. The properties `Price` and `Product` (reference) of an `Order line` is updated. As you see, the `Price` on the Order line is set equal to the price of the `Product`.

{% endtab %} {% tab title="Batch update" %} This example updates the Amount property of all Order Lines. Price and Units are retrieved and the Amount is calculated independently for each record.

{% endtab %} {% endtabs %} {% tabs %} {% tab title="Value processor " %} You may use the [value processor](https://docs.appfarm.io/reference/platform-concepts/value-processor) inside the Update Object action node. For example, to increase a value by 1.

Data binding to the same property, then tick "Value Processor"

{% endtab %} {% tab title="Self properties and dependencies" %} Imagine the following simple scenario. You want to set Property 1 to 20, and you want to set `Property 2` equal `Property 1` in the same Update Object operation

In the above example: if both `Prop 1` and `Prop 2` was 0 by default, then `Prop 2` will still be 0 after this update. The reason is that Data Binding defaults to the *old value* of the bound property. If you want to access the *new value*, you must use a function, and add `prop1` from the Self Properties list, as illustrated below:

In the function editor, as in the screenshot above, you may expand the data source in the left pane and add the same property as a function parameter from there. That will imply use the old value, and not the new value (self-property). \ \ \&#xNAN;*Note that you may only add properties directly at the data source itself as self-properties, and not reference properties (e.g. if you are updating Order Line.Product and Order Line.Price in the same operation, you cannot select Order Line.Product.Product Price as self-property)* {% endtab %} {% tab title="Multi cardinality - Value processor" %} Sometimes you want to update an Object Class Property having [Cardinality Many](https://docs.appfarm.io/reference/data-model/object-class-properties), but you want to keep the existing list of references and add (or remove) a set of references. You can use the [Value Processor](https://docs.appfarm.io/reference/platform-concepts/value-processor) for that.

When clicking "Add Selection" you may select the data source holding the references you want to add

{% endtab %} {% endtabs %} ## Properties

Property	Description
Data Source	Select a data source that contains the object(s) to update.
Selection	Available if the selected Data Source is a many-cardinality data source. Define the objects to update. `All objects` `Selected object(s)` `Object in context` `Filtered selection`
Filter	Available when Selection is Filtered selection. Define the filter to apply to the data source.
Values on update	Set new values for any object class properties in the defined object(s).