Database - Data Models into Database Designs - Discussion

Discussion Forum : Data Models into Database Designs - General Questions (Q.No. 4)
A primary key should be defined as:
Either of the above can be used.
None of the above are correct.
Answer: Option
No answer description is available. Let's discuss.
4 comments Page 1 of 1.

Dipali said:   7 years ago
Obviously. We don't need to define as not null because whenever it is set the column becomes automatically not null.

Mateti shiva said:   8 years ago
Primary is always not null then why should we define again it as not null. Answer is none of the above.

DilipM19 said:   9 years ago
Primary key is an identifier or field which uniquely defined a record in entity(generally table).

Anu said:   1 decade ago
Primary key means it is not null and duplicate values are not allowed.

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