Links

What is a Link ?

The definition of a 1:N relationship allows two business objects to be linked together. If we take the example of the supplier and the product, there is 1 supplier for N products. This section presents what the Simplicité engine does with the configuration of objects, attributes and relationships.

Technical key of the business object

From the definition of the physical object and attribute names, a table and a column are created in the database. In reality, as soon as a business object is created, 5 default columns are created, the technical fields. This can be verified by testing an SQL query via the "DB Access" shortcut as seen in the previous chapter:

select * from trn_supplier;

We obtain the following columns:

row_id	created_dt	created_by	updated_dt	updated_by	trn_sup_code

The row_id column is what we call the technical key. It is generated and managed by the base, so there is no need to create ID attributes for your objects.

These 5 columns are not intended to be visible to the user.

Functional key of the business object

The functional key is a set of fields defining the functional uniqueness of the business object. Thus, if we decide that the functional key of the customer is composed of his name and his first name, then we cannot have two customers with the same name + first name.

Every business object must have a functional key. If there is no key, Simplicité will only allow the creation of one record, which will have an "empty" functional key. The second record, also having an "empty" functional key, will trigger an error because the functional key already exists.

Foreign key

A link between two objects is defined:

• physically, by a column in the referencing object's table, pointing to the row_id column of the referenced object
• in terms of configuration, by:
  • an attribute of type Internal ID/Technical Key (created automatically when the relationship is created),
  • an object field with the following information :
    • the object referenced in "Joined object"
    • empty "referenced field"

Joined fields

When there is a 1:N relationship between two objects, it becomes possible to add joined fields to the referring object. In our example, it is possible to display supplier information on the product form.

There are three ways to join fields:

• when creating the relationship between two objects
• by using template editor
• by manually creating a correctly configured object field

The joined field is defined:

• physically, by the joined object
• in terms of configuration by an object field linking the joined object's field to the referencing object, and containing:
  • the referenced object in "linked object"
  • the foreign key used in "reference field"

Virtual link

A virtual link enables you to access a business object's data without having to go though the model.

This works by creating a "virtual" link between two business objects. This link doesn't come with a physical column, therefore no foreign key is created in the child object's table. The data is retrieved through an SQL query configured on the link between the two objects.