1 Choose a correct one The order by command is especially us

1. Choose a correct one. The order by\' command is especially useful when the listing order is important. The default order is ascending, descending (2 points (3 points) 2. What type of integrity is enforced when a primary key is declared? What is the difference between the COUNT aggregate function and the SUM aggregate function? (5 points) Based on the dependency diagram, create a database whose tables are at least in 3NF, showing the dependency diagram for each table. 4. (10 points) C1 C2 C3 C4 C5

Solution

Answers:

1.The default order is ascending for order by command. you can use DESC keyword to sort the records in descending order.

2.When primary key is declared row integrity is enforced.

Row Integrity reffers to having single unique identifier in each row so that each row can be distinguish.This single unique identifier is used to specify primary key.

3. The count function returns the no of values of the required column whereas sum function returns the total sum of numeric values.