Multiple choice technology databases

Which of the following is TRUE about Primary Key?

  1. Same value of Primary Key can appear in more than one row in the table

  2. A Primary key defined column can be of type LONG

  3. A column that is defined as Primary Key cannot contain NULL value

  4. Both A. and B.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A Primary Key uniquely identifies each row in a table and cannot contain NULL values. This ensures entity integrity. Primary Key values must be unique across all rows, making option A incorrect. LONG is not a standard SQL type for primary keys.

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