identifying candidate keys

hi lovemore,

 

can you please explain in which table you wants to apply candidate key.

 

for your reference -

 

A candidate key is a column, or set of columns, in a table that can uniquely identify any database record without referring to any other data. Each table may have one or more candidate keys, but one candidate key is unique, and it is called the primary key. This is usually the best among the candidate keys to use for identification.