A Business Object May Define Business Rules

A business object may define business rules that govern the behavior of entities of this type.

Simple element-level validation is supported by schema attributes. Note that element-level validation is executed before any maintenance object processing. For more sophisticated rules you create Validation algorithms and associate them with your business object. BO validation algorithms are only executed after "core validation" held in the MO is passed.
A Pre-Processing algorithm may be used to "massage" a business object's elements prior to any maintenance object processing. For example, you may use this type of algorithm to default element values.
A Post-Processing algorithm may be used to perform additional steps such as creating a To Do Entry or add a log record as part of the business object logical transaction. These plug-ins are executed after all the validation rules are executed.
An Audit algorithm may be used to audit changes made to entities of this type.
Any time a business entity is added, changed or deleted, the system detects and summarizes the list of changes that took place in that transaction and hands it over to Audit plug-ins associated with the business object. These plug-ins are executed after all the post-processing rules are executed. It is the responsibility of such algorithms to log the changes if and where appropriate, for example as a log entry or an entry in an audit trail table or an entry in the business event log

By default all elements of the business object are subject to auditing. You can however mark certain elements to be excluded from the auditing process using the noAudit schema attribute. Marking an element as not auditable will prevent it from ever appearing as a changed element in the business object's audit plug-in spot. Refer to the "Schema Tips" context sensitive zone associated with the Business Object maintenance page for more information on this attribute.

Refer to Business Object - Algorithms for more information on the various types of algorithms .

The system applies business object rules (schema based and algorithms) whenever a business object instance is added, changed or deleted. This is only possible when the call is made via the maintenance object service. For example, when made via business object interaction ("invoke BO"), the MO's maintenance page or XAI services that reference the BO or the MO service, etc. In addition the system must be able to determine the business object associated with the actual object being processed. To do that the Maintenance Object itself has to have a Determine BO algorithm plugged in. If the business object cannot be determined for a maintenance object instance business object rules are not applied.

Note:

Pre-Processing is special. The pre-processing algorithm plug-in spot is unique in that it only applies during a BO interaction. It is executed prior to any maintenance object processing. It means that when performing add, change or delete via the maintenance object service, the pre-processing plug-in is not executed.

CAUTION:

Direct entity updates bypass business rules! As mentioned above, it is the maintenance object service layer that applies business object rules. Processes that directly update entities not via the maintenance object service bypass any business object rules you may have configured.