Given the following code excerpt that defines an SAP HANA database table:DEFINE TABLE demo_table{KEY field1 : REFERENCE TO abap.clnt(3);KEY field2 : abap.char(1332);@Semantics.quantity.unitOfMeasure : 'demo_table.field4'field3 : abap.quan(2);field4 : abap.unit(2);}Which field is defined incorrectly?