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Multi-level collections

Latest in a series of articles about Oracle 9i's new features.

O'ReillyNet: Part 6 of Oracle 9i features.

New to Oracle 9i, you can now nest collections within collections, also referred to as support for "multi-level collections." A collection is a data structure (actually, three different, but similar data structures: index-by tables, nested tables, and varying arrays) that acts like a list or array. Collections are, in fact, the closest you can get to traditional arrays in the PL/SQL language, though there are a number of differences. Developers use collections to manage lists of information in their programs—or even within columns in a database table.

A good feature. Might be useful in implementing complex business logic when you choose to enhance security using stored procedures.