During import the system can map an id value to an existing entity in the database to import such a reference field. However, for large databases (and large import files) this takes a very long time to process, as the EntityDatatype's importMapping function is one by one loading the whole array of entities for that type for every row of the import.
During import the system can map an id value to an existing entity in the database to import such a reference field. However, for large databases (and large import files) this takes a very long time to process, as the EntityDatatype's importMapping function is one by one loading the whole array of entities for that type for every row of the import.