Chapter 4. Using Collections
A collection is a single-dimensional structure of homogeneous elements. Behaviorally speaking, it is quite similar to an array and a list structure available in other third generation languages. First introduced in Oracle 7 as PL/SQL tables, Oracle 8i rebranded collections as Index-by tables. Oracle 8i also introduced persistent collection types, namely nested tables and varrays. Oracle Database 9i renamed Index-by-tables to associative arrays.
Oracle Database offers a wide scope of usability of collections in PL/SQL programming. The language semantics not only allow you to create and maintain collections, but also provides multiple methods for array operations. This chapter helps you to understand the collection types in Oracle and, most importantly, which types suit a given problem. The chapter outline looks like this:
- An introduction to collections
- Categorization
- Selection of an appropriate collection type
- Associative arrays
- Nested tables
- Varrays
- PL/SQL...
