Associations Overview - Documentation for Ar System 21.3

An association is a Action Request System object that describes relationships between entries in AR System forms. The association enables you to manage relationships between entries in two forms to support referential integrity, cascade deletes, and archiving related entries.

An association defines a relationship between entries in two forms. The relationship can have three cardinality options: One to One, One to Many, and Many to Many. For one-to-one and one-to-many relationships, an association between two forms is defined by specifying one form as primary and another form as secondary. For these relationships, the primary form can have only one entry in the relationship. For many-to-many relationships, there are no primary and secondary forms.

AR System associations are used in a BMC Helix ITSM application primarily for archiving. You can also use these associations with RESTful APIs to get related entries. For more information, see Overview of the REST API.

The value of associations

You can use associations to describe the data model for an application. Enforced associations can eliminate the need to create workflow to restrict operations or to remove related data when an entry is deleted.  Reducing the amount of workflow needed for an application makes it easier to understand your applications. Associations can also be used to govern the behavior of archive definitions. For more information, see Configuring data archiving associations for related forms.

Cardinality

Each association has cardinality, which dictates how the entries in the two forms are related. The options are:

• One to One—A relationship in which an entry from the primary form can be related to zero or one entry in the secondary form.
• One to Many—A relationship in which an entry from the primary form can be related to zero or more entries in the secondary form.
• Many to Many—A relationship in which an entry from the primary form can be related to zero or more entries on the secondary form and an entry from the secondary form can be related to zero or more entries on the primary form.

All cardinality options may have an entry that is related to no other entries. For example, a one-to-one relationship between an employee and email address includes the possibility that an employee might not have any email addresses.