# Populating values from external sources

**External Data Source (EDS)** is an Eximee mechanism that allows form components to be fed with data coming from outside the form itself (e.g. from backend services or dictionaries). Thanks to EDS, components can dynamically fetch and display up-to-date information while the application is being filled out, instead of relying solely on statically defined values.

For components, we can define the following external data sources:

| Source type                | Source description                                                                                                                                                                                                                                                                                                                                                 |
| -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **DICTIONARY**             | Populated with data from a dictionary. Description in: [Attaching a dictionary data source](https://docs.eximee.com/documentation/documentation-en/budowanie-aplikacji/interfejs-uzytkownika/formularze/praca-z-komponentami-bazowymi/zasilanie-wartosciami-z-zewnetrznych-zrodel/podpiecie-slownikowego-zrodla-danych).                                           |
| **ENTRY\_SERVICE**         | Service for the application. Description in: [Example of attaching in a page service or application component](https://docs.eximee.com/documentation/documentation-en/budowanie-aplikacji/interfejs-uzytkownika/formularze/praca-z-komponentami-bazowymi/zasilanie-wartosciami-z-zewnetrznych-zrodel/podpiecie-uslugi-na-poziomie-strony-lub-calego-wniosku).      |
| **EXIT\_SERVICE**          | Service for the application. Description in: Example of attaching in a page service or application component.                                                                                                                                                                                                                                                      |
| **EXTERNAL\_SECTION**      | A service corresponding to the section content for direct embedding in the application.                                                                                                                                                                                                                                                                            |
| **PAGE\_SERVICE**          | Service for the application page. Description in: [Example of attaching in a page service or application component](https://docs.eximee.com/documentation/documentation-en/budowanie-aplikacji/interfejs-uzytkownika/formularze/praca-z-komponentami-bazowymi/zasilanie-wartosciami-z-zewnetrznych-zrodel/podpiecie-uslugi-na-poziomie-strony-lub-calego-wniosku). |
| **SERVICE**                | A service corresponding to a key-value map. Description in: [Example of binding a service in the component](https://docs.eximee.com/documentation/documentation-en/budowanie-aplikacji/interfejs-uzytkownika/formularze/praca-z-komponentami-bazowymi/zasilanie-wartosciami-z-zewnetrznych-zrodel/przyklad-podpiecia-w-komponencie-uslugi).                        |
| **SUGGESTER\_SERVICE**     | <p>Suggester (description in: <a href="zasilanie-wartosciami-z-zewnetrznych-zrodel/podpiecie-suggestera-komponent-z-podpowiedziami">Suggester integration</a>). Available only for the Text Field component.</p><p>The availability of the functionality depends on the license and may not be available in all deployments.</p>                                   |
| **UNPARK\_ENTRY\_SERVICE** | Service launched when the application is unparked.                                                                                                                                                                                                                                                                                                                 |

*Example uses of EDS:*

* **Lists from external services:** Selection fields (e.g. *Combobox*) can automatically fill with a list of options retrieved from an external service (Service Proxy), e.g. a list of products or SWIFT codes from an external system.
* **Local dictionaries:** Values can come from *dictionaries* defined in the Eximee Library – e.g. a list of countries, document types – shared between different applications.
* **Suggester (suggestion service):** Text fields can use special services of the *Suggester*type, which suggest or correct the entered value.
* **Page/application services:** EDS also includes services associated with the entire application or page (so-called *Page Service*, *Entry Service*, *Exit Service*), which can fetch data for many fields at once in a single operation (e.g. loading customer data when the application is opened).

{% hint style="info" %}
Demo application: demoUslugi
{% endhint %}