While creating a table, which constraint does not allow insertion of duplicate…

To determine which constraint prevents duplicate values during table creation, let's analyze each option: Option A: UNIQUE / यूनिक Step 1: UNIQUE is a constraint that enforces uniqueness in a column or set of columns. Step 2: It ensures that no two rows can have the same value in the specified column(s). Step 3: Therefore, it prevents the insertion of duplicate values. Option B: DISTINCT / डिस्टिंक्ट Step 1: DISTINCT is a keyword used in SELECT statements to return only unique rows. Step 2: It is not a constraint that can be applied during table creation. Step 3: Therefore, it does not prevent duplicates at the table level. Option C: NOT NULL / नॉट नल Step 1: NOT NULL ensures that a column cannot contain NULL values. Step 2: It does not restrict duplicate values; multiple rows can have the same non-null value. Step 3: Therefore, it allows duplicate entries. Option D: HAVING / हैविंग Step 1: HAVING is used in SQL to filter groups after a GROUP BY clause. Step 2: It is not a constraint applied during table creation. Step 3: Therefore, it does not control duplicate values in the table.