what is primary key,unique key, foreign key? can u teach me
in simple language?
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Answer Posted / rama
primary key:primary key is not allowed null values and
duplicate values.
unique key: this key allows null values but does not allow
duplicate values.
foreign key:
this key is used to refer another table.(i.e)other table
primary key values is used in foreign key table.it makes
relation ship between two tables.
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