A shirt is marked 40% above the cost price and sold

MVCC (Multi-Version Concurrency Control) ensures:

Consider the following Java-like pseudo-code for inserting a node into a Binary Search Tree (BST):

    ```java

    class Node {

Given the following Python-like code snippet: 

   ```python

    class Counter:

        def __init__(self):

Which SQL constraint ensures that a column cannot have NULL values?

What will be the output of the following Python code:

a=[1,2,3,4,5,6]

print(a[-1],a[-1:],a[:-1])

 What is the primary purpose of a "Trigger" in a database?

A `FOREIGN KEY` constraint is used to:

What does the ‘’ element in HTML5 allow you to do?

Which of the following is a non-relational database?

Bitmap indexes are most efficient when: