Question at position 24 What is the difference between a PRIMARY KEY and a UNIQUE KEY?None of thesePrimary key cannot be a date variable whereas unique key can beWe can have only one primary key in a table while we can have multiple unique keysPrimary key can store null value, whereas a unique key cannot store null value.单项选择题

A

None of these

B

Primary key cannot be a date variable whereas unique key can be

C

We can have only one primary key in a table while we can have multiple unique keys

D

Primary key can store null value, whereas a unique key cannot store null value.

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Question at position 35 What is the difference between a PRIMARY KEY and a UNIQUE KEY?Primary key can store null value, whereas a unique key cannot store null value.We can have only one primary key in a table while we can have multiple unique keysNone of thesePrimary key cannot be a date variable whereas unique key can be

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