Chapter 3, Using Collections

Question No.	Answer	Explanation
1	a and c	Associative arrays can have negative integer subscripts, positive integer subscripts and string subscripts. As associative arrays are treated as local arrays, initialization is not required for them.
2	c	Nested tables are an unbounded collection which can grow dynamically.
3	a	Varrays are always dense collections. Sparse varray doesn't exist.
4	c and d	BOOLEAN and NUMBER are not suitable index types for an associative array.
5	a and c	Yes, varray limit can be increased during runtime using the ALTER TABLE statement. If all the cells of a varray are populated with elements, LAST is equal to COUNT. This also holds true when the varray is empty.
6	b	The first DBMS_OUTPUT prints the first element from the default constructor. Once it is reassigned with a value in the executable section, the default values are overwritten.
7	a and c	Varrays are bounded collections which can accommodate data maximum up to the specified limit.
8	a, b, and c	EXISTS doesn't raises any exception. DELETE cannot be used with varrays.