Section: Develop new elements by using Application Explorer (20-25%)
Explanation
Explanation/Reference:
Name
The name of a relation should be postfixed with the name of the table it relates to. For example, CustBankAccounts could be a relation on the BankAccounts table.
If there is only one relation for a table, you can just use the table name for the relation instead.
Relations in the Data Model
A relation should be defined on the table that is holding the foreign key to the relating table.
The Validate
property must be set to Yes.
The system guarantees that data entered in the database fulfills the specified relations.
The Self Relation
If a table has a key, the key must be defined by using relations. Such a relation is called the
'self relation'.
The self relation should not be set up in situations where the fields in the key are all foreign keys (such as relations to other tables) - or more specifically, where the last field in the self relation is a foreign key.
Navigational Relations
Navigational relations are definitions of relations that exist among data in tables where there are no integrity constraints.
Defining a navigational relation benefits the system's Auto Join system when one form is opened from within another form.
Define navigational relations to make it easy to navigate in the application by using related information.
A navigational relation has the Validate property set to No.
The Auto Join system uses relations that are defined at both the involved tables, which means that you only have to define a navigational relation on the one table to the other to make the Auto Join system work both ways.
Configuration Keys
The configuration key that is specified for the field in a relation must be the same key, or in the same tree of keys, as the key used for the related field. If the external field in a relationship can be removed, due to configuration key settings, and the field on which the relation is set is not also removed, you will get a best practices warning.