--- sourceDocument: Australia Enable AI sourceDocumentLink: https://www.servicenow.com/docs/r/intelligent-experiences Release : - australia ft:locale : - en-US ft:publication_title : - Australia Enable AI ft:clusterId : - platai bundleId : - platai workflow : - Platform --- # Configuration item relationships and Knowledge Graph # Configuration item relationships and Knowledge Graph {#ariaid-title1} Release version: Australia Updated May 27, 2026 ![](https://www.servicenow.com/docs/portal-asset/ico-clock) 3 minutes to read Summarize ![AI sparkle icon](https://servicenow.com/docs/portal-asset/ai-sparkle-icon) Summarized using AI This content was generated using new OpenAI-powered functionality. Results are provided on an as is basis and are not guaranteed to be accurate or complete. ## Summary of Configuration item relationships and Knowledge Graph Configuration Item (CI) Relationships in ServiceNow enable the Knowledge Graph to interpret and answer natural language questions about service dependencies and infrastructure topology by utilizing typed parent-child relationships between CIs stored in the CMDB. This functionality allows users to understand how various services, servers, databases, and other CIs relate without needing to write complex queries or manually navigate CMDB tables. Show full answer Show less ## Key Features * **CI Relationship Storage:** Relationships between CIs are stored in the `CMDBRELCI` table, linking a parent CI to a child CI with a defined relationship type expressed as `ParentDescriptor::ChildDescriptor`, enabling bi-directional reading of relationships. * **Natural Language Querying:** Users can ask questions specifying the parent CI class, relationship direction, and child CI class to get relevant dependency and topology information. * **Class Hierarchy Inheritance:** Relationships defined between specific CI classes automatically apply to all higher-level classes in the hierarchy, broadening query results when using more general class terms (e.g., querying for "servers" includes Linux, Windows, UNIX servers, etc.). * **System Properties for Enabling:** CI relationship support in Knowledge Graph is off by default. It must be enabled by setting `snkg.descriptiongeneration.enablecmdbrelci` and `snkg.query.enablecmdbrelci` to `true`. Indexing time is required after enabling before queries return complete results. ## Practical Usage and Query Patterns Typical queries that Knowledge Graph supports include: * Identifying services depending on a specific Linux server. * Finding servers a particular service depends on, including use of class hierarchy to query broader server categories. * Determining computers connected to specific databases. * Multi-hop queries involving relationships across multiple CI types (e.g., databases running on UNIX servers connected to specific network gear). ## Limitations and Recommendations * **Unsupported Query Types:** Negations (queries about non-existent relationships), unspecified relationship types, and skipping steps in multi-hop paths are not supported. * **Workarounds:** Reformulate negation queries to ask about existing relationships, specify explicit relationship types, and avoid skipping intermediate CI relationships when constructing queries. ## Implications for ServiceNow Customers By enabling CI relationship support in the Knowledge Graph, customers can leverage natural language queries to gain clearer insights into service dependencies and infrastructure topology without deep technical querying expertise. This improves operational understanding and decision-making related to IT service management and infrastructure planning. Careful attention to enabling system properties and allowing time for indexing ensures accurate, comprehensive results. Using class hierarchy inheritance and following supported query patterns maximizes the effectiveness of this feature. Configuration item (CI) Relationships enable Knowledge Graph to answer natural language questions about service dependencies and infrastructure topology by storing typed parent-child relationships between CMDB configuration items. The CMDB_REL_CI table stores relationships between configuration items (CIs) in ServiceNow CMDB. Each relationship connects a parent CI to a child CI through a defined relationship type, enabling the Knowledge Graph to understand and traverse the topology of your IT environment.{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-1} CI relationship support in Knowledge Graph enables users to ask natural language questions. You can ask about how services, servers, databases, and other CIs relate to one another without writing queries or navigating CMDB tables directly.{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-2} ## Enabling CI relationship for Knowledge Graph CI relationship support for the Knowledge Graph is inactive by default. Set both of the following system properties to true to enable it{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-12} {#ci-relationships-knowledge-graph__entry__2} | System Property | Purpose | |-|-| | sn_kg.description_generation.enable_cmdb_rel_ci | Enables description generation for CI relationship data | | sn_kg.query.enable_cmdb_rel_ci | Enables Knowledge Graph querying against CI relationship data | [Table 1. System properties for CI relationship support] Note: After enabling both properties, allow time for CI relationship data to be fully indexed before running queries. Results may be incomplete until indexing is complete. ## How CI relationship data is stored Each record in the CI relationship table represents a bi-directional relationship between two CIs. Relationships are described by a relationship type that consists of a parent to child relationship and child to parent relationship, separated by double colons:{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-3} `::`{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-4} This means every relationship can be read in two directions:{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-5} * Parent → child: read using the parent to child relationship (parent descriptor) * Child → parent: read using the child to parent relationship (child descriptor) For example, a record in the CI relationship table has Bond Trading (cmdb_ci_service) as the parent, lnux100 (cmdb_ci_linux_server) as the child, and a relationship type of `Depends on::Used by`. This relationship is read as:{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-6} * Bond Trading depends on lnux100 * lnux100 is used by Bond Trading Note: The direction of the relationship affects how you phrase queries to the Knowledge Graph. Parent-to-child queries (for example, "depends on") return more reliable results than child-to-parent queries (for example, "used by"). ## Knowledge Graph support for CI relationships The Knowledge Graph can answer questions about CI relationships when the query clearly specifies all three of the following:{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-7} * The class of the parent CI (for example, service) * The relationship direction --- either the parent to child relationship or child to parent relationship (for example, depends on) * The class of the child CI (for example, Linux server) ## Class hierarchy inheritance When you define a relationship between two CI classes, the Knowledge Graph automatically extends that relationship to all classes higher up in the CI class hierarchy. This means users can query at a more general class level and still get results across all matching subclasses.{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-8} For example, a relationship defined between service and linux server also applies to server, which is a parent class of Linux server in the hierarchy. Querying for servers rather than Linux servers returns results across all server subclasses --- including Linux server, windows server, UNIX server, and others.{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-9} Note: If a query returns fewer results than expected, try using a broader parent class in the hierarchy (for example, "server" instead of "Linux server") to include all inherited CI types. ## Supported query patterns The following table shows examples of queries the Knowledge Graph can answer using CI relationship data. Each query specifies a parent class, a relationship descriptor, and a child class.{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-10} {#ci-relationships-knowledge-graph__entry__8} | Scenario | Example Query | |-|-| | Service that depends on a specific Linux server | Which services depend on 'lnux100' Linux server? | | Servers that a specific service depends on | 'Bond Trading' service depends on which UNIX server? | | All server types a service depends on (using hierarchy) | 'Bond Trading' service depends on which server? | | Computers connected to a database | Which databases are connected by computers? | | Multi-hop relationship across three CI types | What database runs on UNIX server that connects to 'nc6500-a01' network gear? | [Table 2. Supported query patterns] ## Unsupported query patterns The following query types are not currently supported. Use the recommended alternatives to get the results you need.{#ci-relationships-knowledge-graph__ci-relationships-knowledge-graph-p-11} {#ci-relationships-knowledge-graph__entry__21} | Limitation | Unsupported Query | Recommended Alternative | |-|-|-| | Negation of a relationship | Which business capabilities have no related business applications? | Rephrase to ask for what does exist rather than what does not. | | Unspecified relationship type | Show me services related to Linux servers. | Show me services depending on Linux servers. | | Skipping steps in a multi-hop path | Show me servers in New York. | Show me servers in racks present in datacenters located in New York. | [Table 3. Unsupported query patterns]