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What is a primary key, and how is it different from a unique key?
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Answer Posted / nashiinformaticssolutions
• Primary Key:
o Ensures each row in a table is unique.
o Cannot contain NULL values.
o A table can have only one primary key.
• Unique Key:
o Ensures all values in a column are unique.
o Can contain a single NULL value.
o A table can have multiple unique keys.
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