what is primary key,unique key, foreign key? can u teach me
in simple language?
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Answer Posted / teju
PRIMARY KEY :
IN THE TABLE we can find only one record as
uniqely & also it is not null.
unique key:
uk is to search any record as uniquely& when it
is declared it should be only one null values.
Fk:
fk is to maintain the relations bet two tables
as an duplicate values.means to not null.
e.g
1> stud(stud_id,stud_name);
2> stud_det(stud_id,addr);
In this table stud_id is an pk & In the stud_det as
stud_id is used as an duplicate.
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