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Developing an Application

 

OutSystems

Fetch and Display Data from the Database

One of the most common operations in a data-driven application is fetching data from the database, for example, to display it on the screen. In OutSystems, Aggregates Aggregates provide this functionality.

To fetch data from the database in a mobile app:

  1. On the Interface tab, right-click a screen and select if you want to retrieve data from the database or from the local storage to add an aggregate;
  2. Open the aggregate, and drag the entities from where you want to fetch data from the Data tab to the aggregate;
  3. Access the data using the output list of the aggregate.

To fetch data from the database in a web app:

  1. Drag the aggregate tool from the toolbox to any action flow. Aggregates are typically used in Preparation actions of screens;
  2. Open the aggregate, and drag the entities from where you want to fetch data from the Data tab to the aggregate;
  3. Access the data using the output list of the aggregate.

Example in a Web App

In the following steps we will fetch Places from the database of a web app called GoOutWeb. Then we will use a Table Records widget to display them on the screen.

  1. Add the Preparation action to the Places screen, and open it;
  2. Drag the aggregate from the toolbar to the Preparation action. Then double-click on the aggregate to open it;
  3. Drag the Place entity from the Data tab to the aggregate;
  4. On the screen, add a Table Records Table Records widget from the toolbar;
  5. Set the widget’s Source Record List property to GetPlaces.List. This binds the data to the widget;
  6. Drag the Place entity from the Data tab to the Table Records widget on the screen;
  7. Publish the application.

Fetch and Display Data

Example in a Mobile App

In the following steps, we will fetch Places from the database of a mobile app called GoOut. Then we will use the List widget to display them on the screen.

  1. On the Interface tab, right-click on the screen where you will display the data and select Fetch Data from Database to add an aggregate to the screen;
  2. Open the aggregate and drag the Place entity from the Data tab to the aggregate;
  3. Drag the List List widget from the toolbar onto the screen;
  4. Set the Source property of the widget to GetPlaces.List to bind the data of the aggregate to the widget;
  5. To define what to display, drag the Name and Address attributes of the aggregate from the Interface tab into the List widget;
  6. Publish the application.

Fetch and Display Data