# Data Structures

Data structures are a database for your app.

Objects from data structures:

* are processed in [scenarios](https://readme.directual.com/scenarios/principles-of-scenarios)
* are processed in reports
* can be accessed via [API-endpoints](https://readme.directual.com/api-integrations/api-endpoints-security-layer) and [Webhooks](https://readme.directual.com/api-integrations/webhooks)

By default, the following object properties exist:

* **ID**. This is a unique key to the object. If you change the ID, a new object will be created
* **Who**. Who changed/created an object. Can't be changed from UI, API, or scenario
* **dateCreated**. The date and time when the object was created. Can't be changed from UI, API, or scenario
* **dateChanged**. The date and time when the object was changed. Can't be changed from UI, API, or scenario

{% hint style="warning" %}
The maximum **ID** length is 36 characters!
{% endhint %}

You can add custom fields (properties) and groups for your data structure. Each field has to be a [type from the list](https://readme.directual.com/data/data-types).

{% embed url="<https://youtu.be/-14a_hoVUw4>" %}

### Structure visible name

**Y**ou can set up a visible name of a structure by configuring the fields. The name will be displayed in the objects near links to that structure, in [cards](https://readme.directual.com/web-pages/components/legacy-components/cards), and in selections [form](https://readme.directual.com/web-pages/components/legacy-components/form#link-and-arraylink-quick-search-option).


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