<< Setting the NLS_LENGTH_SEMANTICS Parameter | Using SQL Character Data Types >>

Developing Globalized Applications

Working in a Global Environment 6-27

CREATE TABLE SEMANTICS_CHAR(SOME_DATA VARCHAR2(20));

Check the data types of table

SEMANTICS_CHAR

Select the Connections tab, and then expand the

hr_conn

connection to display

all the tables under Tables. Select the

SEMANTICS_CHAR

table. The data type for its

SOME_DATA

column is listed as

VARCHAR2(20 CHAR)

Drop the

SEMANTICS_BYTE

and

SEMANTICS_CHAR

tables.

In the Tables navigation hierarchy, right-click the name of each table, and from the
menu, select Table, and then Drop. Click Apply, and then in the confirmation
dialog box, click OK.

Set

NLS_LENGTH_SEMANTICS

back to its original setting listed in Step 1. For

example:

ALTER SESSION SET NLS_LENGTH_SEMANTICS=BYTE;

Developing Globalized Applications

This section describes Unicode-related features in SQL and PL/SQL that you can
deploy for multiple language applications. You can insert and retrieve Unicode data.
Data is transparently converted among the database and client programs, which
ensures that client programs are independent of the database character set and
national character set.

Overview of Unicode

Unicode is a universal encoded character set that enables you to store information in
any language, using a single character set. Unicode provides a unique code value for
every 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 Oracle database in two ways:

You can create a Unicode database that enables you to store UTF8 encoded
characters as SQL

CHAR

data types.

You can support multiple language data in specific columns by using Unicode
data types. You can store Unicode characters into columns of the SQL

NCHAR

data

See Also:

Oracle Database Reference for more information on the

NLS_

LENGTH_SEMANTICS

parameter.

Oracle Database Globalization Support Guide for a complete
discussion of choosing or changing a character set, including
length semantics

See Also:

Oracle Database Globalization Support Guide for a complete
discussion of programming with Unicode