In this article, Michael Ceber explains how to write a recursive projection query in C# and Entity Framework Core to efficiently load hierarchical tree structures from a database. He discusses the limitations of traditional queries and presents a recursive method that applies a projection of Category to CategoryDTO and queries all subcategories as needed to a maximum specified depth. This method contains the required projection and makes a recursive call back to itself for each layer down to retrieve all categories. The resulting query is efficient and returns only the necessary data for rest endpoint usage.
