Click on "Add reference" to open a dialog where an application and data group can be selected whose data should be used in the current application. Other data groups from the current application can also be selected here. Click on "Next" when you are done.
In this dialog, the data fields can be selected whose data should be used in the current application. Click on "Finish". The reference is now complete.
Now, a drop-down list could be connected to the reference on an edit page, for example. This is done by selecting the option "Values from references" on the Entries tab. You can define the data field from the reference (e.g. Full name of the user) of your choice as the displayed value. If a new data record is entered on the edit page in the browser, all of the corresponding values from the reference data field will be shown and can be selected. The data in the list is always up-to-date because any changes made in the reference data field will be shown in their latest state when a new data record is being created (i.e. when the edit page is loaded). Changes made in the referenced data group will also be updated in the data records that have already been created.
The reference is created using the data record ID of the referenced data record. All elements, which are linked to reference fields, will automatically be filled with the values of the reference data group when the data record is saved.
Please note that although you can create edit elements that show reference data, the values that are entered by users into these elements will not be saved. If the referenced application or the referenced data group is changed, the internal reference field will be generated again. Data record IDs that have been entered for the previously referenced data group will thereby be lost. If a data record is referenced by a third-party application, the record cannot be deleted until the reference is removed.
The following example shows how an application, where customer data is managed with orders, order items, and products, is represented in a target application using external data groups. Click here to discover how to create connections to external data. Click here to discover how to integrate external data into applications. The data structure is the same in both applications. The "Item" data group contains a reference to the "Products" data group in both applications. To represent the relationship from child data groups to parent data groups using external data access, the foreign key must be defined in the child data group.
The properties dialog of the external data group "Order" is shown here. The "fklid" field is set as the foreign key. It contains the ID of the parent data record from the "Customers" external data group. Click on Foreign key to define a field as the foreign key field. The field used as a foreign key must contain a value that can be used to uniquely identify a parent data record, such as a customer number.
The properties dialog of the external data group "Item" is shown here. The "fklid" field is set as the foreign key. It contains the ID of the parent data record from the "Order" external data group.
The data field that is used in the source application as the foreign key for referencing the record from the "Products" data group may not be added to the data field list here.
The "ref_product" field is entered in this example as the foreign key for the relationship to the "Products" external data group; This data field contains the product ID. Thus, every time an order item is created, the product ID is automatically saved to this reference field as well.
If you are creating a new reference, you can click on "Create reference" to open a dialog where a reference data field can be selected using the option "Data field". This data field's unique value is then used as the foreign key for identifying the corresponding data record. Click here for more information about this dialog.