Apple Newton Programmer’s Newton 2.0 (for Newton 2.0) - Manual (Page 507)

About Special-Purpose Storage Objects 12-1
C H A P T E R 1 2
Special-Purpose Objects for Data
Storage and Retrieval
12
Figure 12-0
Table 12-0
This chapter describes the use of special-purpose objects to augment or replace
the behavior of the system-supplied store, soup, cursor, and entry objects. This
chapter describes
■ the use of entry alias objects to save references to soup entries
■ the use of virtual binary objects to store large amounts of binary data
■ the use of store parts to build read-only soup data into packages
■ the use of mock entry objects to implement your own suite of objects that
provide access to nonsoup data in the same manner as the system-provided
store, soup, cursor, and entry objects.
Before reading this chapter, you should understand the contents of Chapter 11,
“Data Storage and Retrieval,” which provides an overview of the Newton data
storage system and describes how to use stores, soups, queries, cursors, and entries
to meet most applications’ data storage needs.
About Special-Purpose Storage Objects 12
The special-purpose data storage objects described here can be used to augment or
replace the behavior of stores, soups, cursors, and entries.
Entry Aliases 12
An entry alias is an object that provides a standard way to save a reference to a
soup entry. Unless it uses an entry alias to do so, a soup entry cannot save a
reference to an entry in another soup—the referenced entry is copied into the host
entry when the host entry is written back to its soup. However, entry aliases may be
saved in soup entries without causing this problem.
Entry aliases are also useful for providing convenient access to entries from
multiple soups. For example, the built-in Find service uses entry aliases to present
entries from multiple soups in a single overview view.