Why we are using primary key and foreign key in oracle and
difference between primary key and foreign key?
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Answer / ramachandra
we are using primary key and foreign key database designer identify an entity
diffencee b/w primary key and foreign key
1.every table should have one primary key
but foreign key it doesnt any rule we keep more than one foreign key
2.primary key doesn't accept null values
3primary key is parent key
but foreign key is child key it depends only primary key table or column it doesn't allow more than primary key column attributes.
4.primary key doesn't accept duplicate values
but foreign key accepting duplicate values
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