What defines a Circular Reference in data modeling?

A circular reference in data modeling occurs when there are multiple paths to access data between two or more tables, leading to ambiguity in query resolution. This situation arises particularly in relational databases where two or more tables reference each other in such a manner that they create a loop, which complicates how the database engine resolves queries.

In the context of data modeling for tools like Qlik Sense, if there is more than one way to reach the same data, the data model may struggle to determine which path to follow when generating results. This often leads to performance issues, and may result in ambiguous or incorrect data being shown in reports, as the system cannot definitively decide which relationship to prioritize.

Understanding that circular references can introduce complexity is key for data architects when designing their data models. They strive to eliminate these issues by refining their data relationships and ensuring there is a clear, singular pathway to query the data accurately.