What are Split Queries and when should you use them?

Split queries prevent the Cartesian Explosion problem by breaking a single massive JOIN query into multiple smaller SQL queries.

When eager loading multiple collection navigation properties (1-to-N), standard JOINs duplicate parent data for every child row. AsSplitQuery() commands EF Core to issue separate queries for the parent and each collection, merging them in-memory. Use it when eager loading multiple collections causes performance degradation.