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c# and SQL interview question Video :- What is the difference between unique key and primary key?
Unique key can have nulls .Primary key cannot have nulls.
In a single table we can create multiple unique keys.In a single table we can have only one primary key.
Unqiue key creates a non-clustered index by default.Primary Key created a clustered index by default.
Both unique keys and primary keys can be referenced by foreign key.
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