When youcreate a database, youspecify the character
set that will be used for encoding the various characters stored in the database.
Youcan optionally specify a secondary character set as well (which is known as
the National Language Set, or NLS). The secondary character set will be used for
NCHAR and NVARCHAR2 columns. For example, you may have a description
field in which youwant to store Japanese characters while the rest of the database
uses English encoding. You would specify a secondary character set that
supports Japanese characters when you create the database, and then use the
NCHAR or NVARCHAR2 datatype for the columns in question.
84 | Chapter 4: Oracle Data Structures
Starting with Oracle9i, youcan specify the length of NCHAR and NVARCHAR2
columns in characters, rather than in bytes. For example, you can indicate that a
column with one of these datatypes is 7 characters. The Oracle9i database will
automatically make the conversion to 14 bytes of storage if the character set
requires double-byte storage.
Oracle Database 10g introduced the Globalization Development Kit
(GDK), which is designed to aid in the creation of Internet applications
that will be used with different languages.
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