Maintaining Business Rules With Function Hierarchy Diagrammer

Overview Business rules: Restrictions that apply to the data set and changes in it or Specific automatic actions that must take place after some change in the set of data

Business Rules in the Repository Not a single Repository object Part of the data model –Uniqueness constraint –Mandatory relationship Part of the descriptive text of functionsPart of the descriptive text of functions –Price Paid may not exceed default price.

Declaring Business Rules as Relational Constraints Uniqueness constraint Referential constraint Integrity constraint Non-transferability constraint Exclusivity constraint (arc)

Business Rules That Cannot Be Expressed as Relational Constraints Members may not rent more than two ‘hot’ MOVIES at the same time. Terminated MEMBERSHIPS cannot take out new RENTALS. MEMBERSHIPS cannot be terminated when they have open RENTALS.

Documenting More Complex Business Rules Pure text Related to specific entities or business functions Coding during build

Business Rule as Business Function Separate business rule hierarchy Can be associated with entities Can be associated with other business functions

Business Rules Change Event Authorization Static Data Data Operation Business Rule Classification

Static Data Rule Examples Multiple Entity Business Rules Static Data Multiple Attr Entity Attribute...Duration of Movie must be positive... Attribute... Date Lost of Copy must be after Acquire Date... Multiple Attr Entity …no more than 250 Bookings... …cannot rent more than two hot Movies simultaneously... Multiple Entity

Create Data Operation Change Event Data Operation Rule Examples Update Delete...no new Rentals allowed for terminated Memberships... Create Update …Memberships can not be terminated when there are still open Rentals......Price History may not be deleted when Effective Date is in the past... Delete Authorization

Change Event Change Event Rule and Authorization Rule Examples Change Event...when Rental Items are overdue a reminder must be printed and mailed... Authorization...only managers may terminate Memberships with reason ‘Expelled’... Authorization

Using the Business Rule Hierarchy Other Delete Rules Relationship Delete Delete Rules Update Rules Delete of Membership only permitted a year after termination Price History may not be deleted when Effective Date is past

Creating the Rules Use FHD or RON

The Rule Hierarchy

Setting Up the MXD

Making the Associations

Implementing Rules At analysis level, by setting constraints: Ranges, Allowable Values, FKs At DB design level, check constraints. At App design level, code modules or packages.

Auditing Rules Single place to start checking Add notes to rules and objects where implemented. Use existing or new reports to check.

Summary Capturing business rules is an important analysis task. Business rules are modeled: –Within the entity relationship model –Descriptive texts –Functions in the Business Rule hierarchy