| interface  | IAnalysisItem | For HP use. | 
| interface  | IAnalysisItemFolder | For HP use. | 
| interface  | IAssetRelation | Represents a directed relation between two assets. | 
| interface  | IAssetRepositoryItem | Represents a folder or an asset file stored in the repository. | 
| interface  | IAttachment | Represents a single file or Internet address attached to a field object. | 
| interface  | IAuditProperty | Represents a property associated with an AuditRecord. | 
| interface  | IAuditRecord | A data change that is tracked. | 
| interface  | IBaseFieldEx | Represents a basic data field or entity, such as an attachment. | 
| interface  | IBaseFieldExMail | Services to support mailing factory items. | 
| interface  | IBaseline | For HP use. | 
| interface  | IBaselineRoot | For HP use. | 
| interface  | IBaseParam | A business component parameter or runtime parameter. | 
| interface  | IBPComponent | An instance of a Component in a Business Process. | 
| interface  | IBPIteration | The design-time definition of a business component iteration. | 
| interface  | IBPIterationParam | An instance of a business component parameter that belongs to a single iteration. | 
| interface  | IBPParam | An instance of a Component Parameter in a business component. | 
| interface  | IBPStepParam | A step parameter for a manual run of the business process test. | 
| interface  | IBug | Represents a defect. | 
| interface  | IBusinessProcess | Represents a single Business Process Test. | 
| interface  | IBusinessProcess2 | Represents a single Business Process Test. | 
| interface  | IBusinessProcess3 | Represents a single Business Process Test. | 
| interface  | IChange | Obsolete. | 
| interface  | IChangeEntry | Obsolete. | 
| interface  | IComparison | For HP use. | 
| interface  | IComparisonNode | For HP use. | 
| interface  | IComponent | Represents a business component. | 
| interface  | IComponent2 | Represents a single Business Process Component. | 
| interface  | IComponent3 | Represents a single Business Process Component. | 
| interface  | IComponentFolder | Represents a business component folder. | 
| interface  | IComponentParam | Services for managing Business Process Test parameters. | 
| interface  | IComponentStep | Represents a step in a business process test. | 
| interface  | ICoverageEntity | Represents the association between a requirement and another entity that covers it. | 
| interface  | ICycle | Represents a Cycle. | 
| interface  | IDashboardFolder | For HP use. | 
| interface  | IDashboardPage | For HP use. | 
| interface  | IDashboardPageItem | For HP use. | 
| interface  | IDesignStep | Represents a single design step in a test. | 
| interface  | IFavorite | For HP use. | 
| interface  | IFavoriteFolder | For HP use. | 
| interface  | IHost | Represents a single host server. | 
| interface  | IHostGroup | Services for managing a group of host servers. | 
| interface  | ILibrary | For HP use. | 
| interface  | ILibraryFolder | For HP use. | 
| interface  | ILibraryPart | For HP use. | 
| interface  | ILink | Represents an association between a Bug and another entity. | 
| interface  | IParameterValue | Represents a test parameter value entity. | 
| interface  | IQCResource | Represents a file or folder stored in the Quality Center repository. | 
| interface  | IQCResourceFolder | Represents a QC resource folder. | 
| interface  | IRelease | Represents a Release. | 
| interface  | IReleaseFolder | Represents a Release Folder. | 
| interface  | IReq | Represents a requirement for which testing must be performed. | 
| interface  | IReq2 | Represents a requirement for which testing must be performed. | 
| interface  | IRTParam | A Business Process Test runtime parameter. | 
| interface  | IRun | Represents a test run. | 
| interface  | IRun2 | Represents a test run. | 
| interface  | IStep | Represents a test step in a test run. | 
| interface  | IStep2 | Represents a test step in a test run. | 
| interface  | ITask | An asynchronous action. | 
| interface  | ITaskLog | An entry in the log of an asynchronous action. | 
| interface  | ITest | Represents a planning test. | 
| interface  | ITestParameter | A parameter for a manual test. | 
| interface  | ITestSet | Represents a series of tests to be run as a group to meet a specific testing goal. | 
| interface  | ITrace | Represents a traceability association between two requirements. | 
| interface  | ITSTest | Represents a test instance, or execution test, in a test set. | 
| interface  | ITSTest2 | Represents a test instance, or execution test, in a test set. | 
| interface  | ITSTest3 | Represents a test instance, or execution test, in a test set. | 
| interface  | IUserAsset | Represents any entity known to the testing tool that is not otherwise represented in Quality Center. |