8.5.7 Using Temporary Collections

Collections let APEX store one or more rows of temporary information. At runtime, you create a named collection with the APEX_COLLECTION package. A session can contain multiple collections, and APEX clears them automatically when the session ends.

• Key Collections Concepts
  A collection requires no formal definition. Instead, you use its predefined generic columns, such as N001, N002, C001, C002, and D001, according to the number and type of values you need to store.
• Tips for Maintainable Collection Use
  For additional ease of maintenance, create a view for the collection query so your pages can work with the meaningful column names anywhere they need to.