Answer:
Changing the customer number on a record in the Orders table to a number that does not match a customer number in the customer table would violate referential integrity.
If deletes do not cascade, deleting a customer that has orders would violate referential integrity.
If deletes cascade, customer can be deleted and all orders for that customer will automatically be deleted.
There are multiple devices that emit radio waves. The most obvious is are radiod and microwaves (yes, the food cooker). Wireless applicances also emit radio waves. But don't confuse everything to use microwaves. Some applicances use frequencies instead of radio waves. Some applicances that use frequencies are toy control remotes and a garage door.
I hope this helps! Please make sure ask me if you need more clarity!
I would say two car length rule. I am not sure what the official license rule is or if it has been changed, but originally the rule was 3 seconds usually depending on how fast the car is going. The faster you are going, the longer it takes to stop. So two-car length rule would probably be the best choice. Definitely not A.
Answer:
This is the case of redundancy or the repeated data. It means that the same data is being repeated again and again. And its the wastage of time and memory both. The redundancy must be removed in all circumstances. However, we cannot as without it proper normalization of data is not possible.
Explanation:
The answer is self explanatory.
