Questions

Database provides necessary means to achieve this abstraction. By structure of a database we mean the data types, relations, and constraints that should hold on the data.

The words do, does and did often cause confusion in the English language. They are all forms of the verb to do.

It is also common to use do, does and did as auxiliary verbs (or helping verbs) together with another verb in its base form. This is used to create negative sentences, questions, or for adding emphasis.

Examples :: 

* Russel did a great job on his debut match for team.

* Did you catch the train this morning?

* When did they arrive home?

Can’t delete a row from primary table if there are related rows in secondary table.

The USSR( now a Common Wealth of Independent States) is spread over Europe and Asia

A Hole.

When you are digging a hole the more you take out the soil, the igger the hole becomes.