0 votes 0 votes Do foreign key always refers to a primary key in some other table? himgta asked Aug 5, 2018 himgta 480 views answer comment Share Follow See all 15 Comments See all 15 15 Comments reply Show 12 previous comments srestha commented Aug 5, 2018 reply Follow Share Since the purpose of the foreign key is to identify a particular row of referenced table, it is generally required that the foreign key is equal to the candidate key in some row of the primary table, or else have no value (the NULL value.[2]). This rule is called a referential integrity constraint between the two tables.[5 https://en.wikipedia.org/wiki/Foreign_key read it unique key means here primary key only 1 votes 1 votes Shaik Masthan commented Aug 5, 2018 reply Follow Share Candidate key also find a row uniquely in the table... Don't forget that primary key is one of the candidate key 0 votes 0 votes srestha commented Aug 5, 2018 reply Follow Share but foreign key doesnot refer candidate key, it refers only primary key It is by definition right? 0 votes 0 votes Please log in or register to add a comment.