1. Complex Join in the BMM layer represents the relationship between the logical tables and its columns.
2. It makes the best decision about sql request to generate based on the logical query request.
3. Use of complex joins, can create one to many relationships and not the logical foreign key.
4. We can’t use the expression builder in the complex join because it will be grey out. You can only use the types of joins like inner or outer.
5. Logical joins are automatically created if both of the following statements are true:
6. You create the logical tables by simultaneously dragging all required physical tables to the Business Model and Mapping layer.
7. The logical joins are the same as the joins in the Physical layer
8. Logical tables in a BMM layer can have multiple logical tables sources (LTS). Complex join actually is an intelligent join between LTSs of two logical tables in BMM Layer.