What are different types of Keys? Please explain all the
keys with a suitable example.
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Answer Posted / abdul malik(new college)
keys-A key allows us to identify a set of attributes and
thus distinguishes entities from each other.keys also help
uniquely identify relationships,and thus distinguishes
relation with each other.
different types of keys:
(i)super key
(ii)candidate key
(iii)primary key
(iv)unique key
(v)foreign key
sk-it is a set of one or more attributes that allows us to
identify uniquely an entity set.
ck-a super key for which no subset is a superkey is called
a candidate key.
pk-In a table pk does not take no repetation and does not
allow null values.
fk-it acts as a referential order.it refers one table from
the another one.
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