What is a set? What will be an ideal ...

[luminitza]

What is a set?
 
  What will be an ideal response?

Question 2

In general, optimistic locking is the preferred technique for Internet databases.
 
  Indicate whether the statement is true or false

[Eunice618]

Answer to Question 1

A key is a field that identifies a record. We can have primary keys, which uniquely identify a record, unique secondary keys and nonunique secondary keys. The term set refers to all records having the same nonunique secondary key. For example, we may have sets based on ZIP code as a nonunique secondary key.

Answer to Question 2

TRUE