Siebel CRM Question:

When a multi-value link has been configured with a primary join?which is the typical situation?there are circumstances in which the foreign key used by this join to identify the primary record is unable to find the primary. For example, this can happen when the primary record has been deleted from the multi-value group or the multi-value group is newly created and has no records.
In such cases, the multivalue link can be configured to update the primary foreign key to a value of NULL, or to a special value of NoMatchRowId, depending on your requirements. This behavior is configured through the Check No Match property of the Multi Value Link object type, and has performance consequences.