Many-to-many (m:n) relationships add complexity and confusion to your model and to the application development process. The key to resolve m:n relationships is to separate the two entities and create two one-to-many (1:n) relationships between them with a third intersect entity.Check this for in-depth explanation:https://www.ibm.com/docs/en/informix-servers/12.10?topic=SSGU8G_12.1.0/com.ibm.ddi.doc/ids_ddi_186.htm