Link Rule Requirements

A link rule is a required component of a reconciliation task. It establishes a link between a top-level object and attribute in Data Set 1 and an attribute of the object in Data Set 2. Link rules are often based on unique identifiers. The attribute most commonly used to link assets and deployed assets is a serial number or asset tag. The attribute most commonly used to link configuration items (CIs) with actual CIs is ACTCINUM, the actual CI number.

A link rule consists of the following elements:

a unique link rule name
a brief description of the link rule (optional)
The customer associated with the link rule. This field is used to limit the records included when a reconciliation task is processed. If you specify a customer, you can apply the link rule only to reconciliation tasks created for that customer. If you do not specify a customer, you can apply the link rule only to reconciliation tasks that are not associated with a customer.
data set specifications for Data Set 1 and Data Set 2 that indicate what data to reconcile
one or more link clauses

Each link clause identifies an object and attribute in Data Set 1 to compare with a specific attribute of an object in Data Set 2. The Link Clauses table window on the Link Rule tab lists link clauses. For more information about the elements of a link clause, see Link Clauses.

Before you can save a link rule, you must satisfy the following requirements:

The link rule name must be unique.
You must create at least one link rule clause.

Clauses must be valid expressions. When you save a link rule, the system uses the following rules to determine whether clauses are valid expressions. If the system determines a clause is not valid, it displays an error message and does not save the link rule.

Each open parenthesis must have a corresponding close parenthesis.

The number in the Sequence field must be unique.

Note: If you enter sequence numbers in random order, the system sorts the clauses and displays them in ascending numerical order when you save the record.

All rows except the row with the highest sequence number must have a value specified in the Sequence Operator field.
The row with the highest sequence number must not have a sequence operator (After the system sorts the clauses, this is the last row in the table window.).