Oracle SQL Developer
Oracle SQL Developer
Oracle SQL Developer
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<strong>SQL</strong> and PL/<strong>SQL</strong> Programming with Unicodeprocedural languages. Both <strong>SQL</strong> and PL/<strong>SQL</strong> can be embedded in other programminglanguages.<strong>Oracle</strong> Express provides products such as <strong>SQL</strong> and PL/<strong>SQL</strong> for inserting andretrieving Unicode data. Data is transparently converted between the database andclient programs, which ensures that client programs are independent of the databasecharacter set and national character set. In addition, client programs are sometimeseven independent of the character data type, such as NCHAR or CHAR, used in thedatabase.The PL/<strong>SQL</strong> and <strong>SQL</strong> engines process PL/<strong>SQL</strong> programs and <strong>SQL</strong> statements onbehalf of client-side programs such as server-side PL/<strong>SQL</strong> stored procedures. Theyallow PL/<strong>SQL</strong> programs to declare CHAR, VARCHAR2, NCHAR, and NVARCHAR2variables and to access <strong>SQL</strong> CHAR and NCHAR data types in the database.This topic describes Unicode-related features in <strong>SQL</strong> and PL/<strong>SQL</strong> that you can deployfor multilingual applications. It includes the following topics:■■■Overview of Unicode<strong>SQL</strong> NCHAR Data TypesUnicode String LiteralsSee Also:■■<strong>Oracle</strong> Database <strong>SQL</strong> Reference for information on <strong>SQL</strong>PL/<strong>SQL</strong> User's Guide and Reference for information on PL/<strong>SQL</strong>11.3.1 Overview of UnicodeUnicode is a universal encoded character set that enables you to store information inany language, using a single character set. Unicode provides a unique code value forevery character, regardless of the platform, program, or language.Unicode has the following advantages:■ It simplifies character set conversion and linguistic sort functions.■ It improves performance compared with native multibyte character sets.■ It supports the Unicode data type based on the Unicode standard.You can store Unicode characters in an <strong>Oracle</strong> database in two ways:■ You can create a Unicode database that enables you to store UTF-8 encodedcharacters as <strong>SQL</strong> CHAR data types.■11.3.2 <strong>SQL</strong> NCHAR Data TypesYou can support multilingual data in specific columns by using Unicode datatypes. You can store Unicode characters into columns of the <strong>SQL</strong> NCHAR data typesregardless of how the database character set has been defined. The NCHAR datatype is an exclusively Unicode data type.There are three <strong>SQL</strong> NCHAR data types:■ The NCHAR Data Type on page 11-20■ The NVARCHAR2 Data Type on page 11-20Working in a Global Environment 11-19