Back links and link discovery

Back links and link discovery are different implementations of link relationships between artifacts in integrated tools. In both cases, integrations are based on Open Services for Lifecycle Collaboration (OSLC) protocol. With back links, two artifacts are related to one another by a pair of links. Each artifact stores a link that points to the other artifact. With link discovery, artifacts are related by a single link. The source artifact stores the link. The target tool must perform a query against the source tool to discover which source artifacts have a link relationship with a specific target artifact.

When artifacts in different tools are related with back links, both artifacts detect that they are linked to each other because each artifact has a link to the other stored in its data. The relationship is expressed through the use of two separate links, as shown in the following figure.

The image shows two links between object 1 and object 2.

In this type of linking relationship, you do not need to complete extra operations, such as running a query, to discover traceability. However, you must ensure the symmetry and integrity of the linked data. For example, if you remove a link from Tool A, you must ensure that the corresponding link is removed from Tool B.

When link discovery is used to link artifacts, each relationship is expressed through the use of one link from a source artifact to a target artifact. The tool that contains the source artifacts is queried by the tool that contains the target artifact to determine which artifacts are linked.

The query is a supplemental operation. For example, even if Tool A has a set of links that point to Tool B, to complete a full traceability analysis Tool A must run a query to know what is linked from Tool B.

The image shows a link from Tool A to Tool B and a discovered link from Tool B to Tool A.

In this type of linking relationship, you do not need one tool to update the other when links are added or removed. However, to determine traceability, you must complete extra operations. To complete those operations, you typically must authenticate to the other tool's user database and you might need a license.

For integrations based on OSLC specification version 1, back links are used to link between IBM® Rational® DOORS® and the Quality Management (QM) and Configuration Management (CM) domains. The following image shows back links for the integration with QM and CM tools.

The image shows back links to IBM Rational Quality Manager, IBM Rational Team Concert, IBM Rational ClearCase, andIBM Rational ClearQuest.

For integrations based on OSLC specification version 2, back links are used with the tools in the QM and CM domains. Link discovery is used with other tools in the Requirements Management (RM) and with the Architecture Management (AM) domain. When Rational DOORS is integrated with another installation of Rational DOORS, they are linked by using back links. The following image shows these link relationships.

The image shows the linking implementation for the integration with QM, CM, RM, and AM tools.

*Links between Rational DOORS and IBM Rational Rhapsody® Design Manager or IBM Rational Software Architect Extension for Design Management are always stored in the Design Management application, even if they were created in Rational DOORS.