Comparing Oracle Collection Types?

Characteristic	Associative Array	Nested Table	Varray
Dimensionality	Single	Single	Single
Usable in SQL?	No	Yes	Yes
Usable as column datatype in a table?	No	Yes; data stored "out of line" (in separate table)	Yes; data stored "in line" (in same table , if < 4,000 bytes)
Uninitialized state	Empty (cannot be null); elements undefined	Atomically null; illegal to reference elements	Atomically null; illegal to reference elements
Initialization	Automatic, when declared	Via constructor, fetch, assignment	Via constructor, fetch, assignment
Subscript Limit	BINARY_INTEGER (-2,147,483,647 .. 2,147,483,647)	Positive integer between 1 and 2,147,483,647	Positive integer between 1 and 2,147,483,647
Sparse?	Yes	Initially, no; after deletions, yes	No
Bounded?	No	Can be extended	Yes
Means of extending	Assign value to element with a new subscript	Use built-in EXTEND procedure (or TRIM to condense), with no predefined	No
Can be compared for equality?	No	Yes, from Oracle Database 10g	No
Can be manipulated with set operators?	No	Yes, from Oracle Database 10g	No
Retains ordering and subscripts when stored in and retrieved from database?	N/A	No	Yes