Variables with character datatypes store text and are manipulated by character functions. Working with character data can range in difficulty from easy to quite challenging. In this chapter, I discuss PL/SQL’s core string functionality largely in the context of single-byte character sets—for example, those that are commonly used in Western Europe and the United States. If you are working with Unicode or with multibyte character sets, or are dealing with multiple languages, be sure to read about globalization and localization issues in Chapter 25.
CLOB (character large object) and LONG, while arguably character types, cannot be used in the same manner as the character types discussed in this chapter, and are more usefully thought of as large object types. I discuss large object types in Chapter 13.