Comment by reaanb2

EF is limited to binary relationships: https://learn.microsoft.com/en-us/ef/core/modeling/relations.... When entities are mapped to rows and relationships to foreign key constraints, it results in a network data model interpretation of SQL databases. The relational model is better conceptualized from a fact-oriented modeling perspective, in which entities map to values, domains to FK constraints, relationships to the association of two or more entity sets in a table, and rows represent propositions about entities rather than entities themselves. However, non-binary relationships don't easily translate into navigational data access (cf. Bachman's paper "The programmer as navigator" about the network data model) and a logical view is difficult for the non-mathematical programmer, while structs and pointers are naïvely easy to understand, that's why ORMs remain popular. The impedance mismatch is less about mapping flat to rich data structures than about the network data model vs fact-oriented perspectives and row-at-a-time vs batch data access.