DBMS class

in the Exercises ation is a relation and a reliational hentation in a relation schema? s the difference between a derived attribute and a stored anrbune in the e? What gives rise to null values in a rolation? what is a null valuese oveen vWmat is tho andidate key? How does a candidate key differ from a between a subset and a proper what is a ary key? How do the propertios 1idatetne sperkeys, candidate koy( superxe? of a primary key differ from those of a car dentiy of the STU-CLASS relation schema s). and the primary key for the folowing relation Student Student Name KHUMAWALA KHUMAWALA Number Student Major Class Name a4 Class Tme oio ACCOUNTING ACCOUNTING BA482 BD445 MW3 0110 KHUMAWALAACCOUNTING BA491 TR2 011o STEDRY TR3 1000 1000 2000 ANTHROPOLOGY AP150 STEDRY MWF9 ANTHROPOLOGY BD445 TR2 KHUMAWALA STATISTICS BA491 BD445 TRA KHUMAWALA STATISTICS ACCOUNTINGBA482 ACCOUNTING 2000 TR2 GAMBLE 3000 GAMBLE BP490 MW4 3000 Define the term "referential integrity constraint." Why is referential integrity important? How is the term "foreign key" used in the context of referential integrity