A **CMDB relationship** is a connection between [[Configuration item|configuration items]] within the [[Configuration management database|CMDB]] as defined by the [[Common Service Data Model|Common Service Data Model]] (CSDM), a reference architecture developed by [[ServiceNow|ServiceNow]] that provides prescriptive guidance on service-related definitions and data modeling within the ServiceNow AI Platform. Configuration management is not effective without relationships between CIs, and CSDM prescribes specific relationship types to ensure consistent data modeling and enable [[Impact analysis (ServiceNow)|impact analysis]], service mapping, and reporting across the ServiceNow AI Platform. CSDM defines prescribed relationships between domain entities, with the relationship type expressed as "Parent relationship::Child relationship." Key relationships include: [[Value Stream Stage (CSDM)|Value Stream Stage (CSDM)]] to [[Business Capability (CSDM)|Business Capability]] and [[Business Process (CSDM)|Business Process (CSDM)]] using "Operationalizes::Operationalized by"; [[Business Capability (CSDM)|Business Capability]] to [[Business Application (CSDM)|Business Application (CSDM)]] using "Provided by::Provides"; Business Application to [[Application Service (CSDM)|Application Service (CSDM)]] using "Uses::Used by"; Application Service to [[Application (CSDM)|Application]] using "Depends on::Used by"; Application to infrastructure CIs using "Runs On::Runs"; [[API (CSDM)|API]] to Application Service and [[Business Service (CSDM)|Business Service (CSDM)]] using "Receives data from::Sends data to"; [[Business Service (CSDM)|Business Service (CSDM)]] and [[Technology Management Service (CSDM)|Technology Management Service (CSDM)]] to [[Service Instance (CSDM)|Service Instance (CSDM)]] types using "Depends on::Used by"; and [[Technology Management Service Offering (CSDM)|Technology Management Service Offering (CSDM)]] to [[Dynamic CI Group (CSDM)]] using "Contains::Contained by." Impact analysis processes traverse these relationships in reverse direction to determine impacted services. Several ServiceNow products such as [[Enterprise Architecture (ServiceNow)|Enterprise Architecture]] have critical dependencies on these prescribed relationships.