In TMF656_Service_Problem_Management_API_User_Guide_v4.0.0.pdf, You provided Resource Model - Picture attached. Would you be able to provide equivalent database Schema, which may be used for RDBMS or NoSQL database. thanks
The Open API data model is just that, a model of the payloads in the API operation. There is no causal relationship between this model and the model you choose to use for persistence.
Having said that, if you are using a document-oriented database (such as Couchbase for example), you may find it convenient that your persisted documents appear similar to the API model. But there is no necessity that this is the case.
More generally, TMF assets (Open API, ODA, SID) do not relate to internal implementation of persistence.
Hope it helps.