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Copyright 2008, Oracle. All rights reserved.

Globalization

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Copyright 2008, Oracle. All rights reserved.20 - 2

Objectives

After completing this lesson, you should be able to: Determine a correct database character set that meets your

business requirements

Obtain globalization support configuration information

Customize language-dependent behavior for the databaseand individual sessions

Specify different linguistic sorts for queries

Retrieve data that matches a search string ignoring case or

accent differences

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Globalization Support Features

Language support Territory support

Character set support

Linguistic sorting

Message support Date and time formats

Numeric formats

Monetary formats

French

data

Japanese

data

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What Every DBA Needs to Know

What is a character set? How are character sets used?

Problems to avoid

Choosing your character set

Obtaining character set information Specifying language-dependent behavior

Using linguistic searching and sorting

Using data conversion

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What Is a Character Set?

The Oracle database supports different classes of character-encoding schemes:

Single-byte character sets

7-bit

8-bit Multibyte character sets, including Unicode

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Understanding Unicode

Supplementarycharacters

AL32UTF8 AL16UTF16

63

EE AA 9E

F0 9D 84 9E

64

C3D0 A4

B6

t

d

0063

00E1

0074

A89E

D834 DD1E

0064

00F60424

c

C3

74

91

Encoding: Representing characters with byte sequences

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7/30Copyright 2008, Oracle. All rights reserved.20 - 9

How Are Character Sets Used?

Oracle Net compares the client NLS_LANGsetting to thecharacter set on the server.

If needed, conversion occurs automatically and

transparently.

Client

Oracle Net

NLS_LANG

Server

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Problems to Avoid

Example:

No conversion occurs, because it does not seem to berequired.

Issue: Invalid data are entered into the database.

Server

Database character set:

AL32UTF8

Client

Windows English

Code page: WE8MSWIN1252

NLS_LANG:

AL32UTF8 Oracle Net

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CREATE DATABASE ...CHARACTER SET US7ASCIINATIONAL CHARACTER SETUTF8 ...

% export NLS_LANG=SIMPLIFIED

CHINESE_HONG KONG.ZHS16GBK

Another Sample Problem

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Choosing Your Character Set

Trade-offs to consider Choosing the correct character set that meets your business

requirements now and in the future

Specifying the character set

Changing the character set after database creation

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Database Character Sets and

National Character Sets

Database Character Sets National Character Sets

Defined at creation time Defined at creation time

Cannot be changed without

re-creation (exceptions in certainconfigurations)

Can be exchanged

Store data columns of type CHAR,VARCHAR2, CLOB, LONG

Store data columns of typeNCHAR, NVARCHAR2, NCLOB

Can store varying-width character

sets

Can store Unicode using either

AL16UTF16or

UTF8

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Obtaining Character Set Information

SQL> SELECT parameter, value2 FROM nls_database_parameters

3 WHERE parameter LIKE '%CHARACTERSET%';

PARAMETER VALUE----------------------- -------------NLS_CHARACTERSET WE8ISO8859P1NLS_NCHAR_CHARACTERSET AL16UTF16

2 rows selected.

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SELECT sysdate FROM dual;

Initialization parameters for the database server

Environment variables for the clients

ALTER SESSIONcommand

Specifying Language-Dependent Behavior

SQL function

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Specifying Language-Dependent

Behavior for the Session

Specify the locale behavior with the NLS_LANGenvironmentvariable:

Language

Territory

Character set

Set other NLS environment variables to:

Override database initialization parameter settings for all

sessions

Customize the locale behavior

Change the default location of the NLS library files

NLS_LANG=FRENCH_CANADA.WE8ISO8859P1

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Language-Dependent and Territory-Dependent

Parameters

Parameter Default Values

NLS_LANGUAGE

NLS_DATE_LANGUAGE

NLS_SORT

AMERICAN

AMERICAN

BINARY

NLS_TERRITORY

NLS_CURRENCY

NLS_DUAL_CURRENCY

NLS_ISO_CURRENCY

NLS_DATE_FORMAT

NLS_NUMERIC_CHARACTERS

NLS_TIMESTAMP_FORMATNLS_TIMESTAMP_TZ_FORMAT

AMERICA

$

$

AMERICA

DD-MON-RR

.,

DD-MON-RRHH.MI.SSXFF AMDD-MON-RRHH.MI.SSXFF AM TZR

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ALTER SESSION SET NLS_DATE_FORMAT='DD.MM.YYYY';

DBMS_SESSION.SET_NLS('NLS_DATE_FORMAT',

'''DD.MM.YYYY''') ;

Specifying Language-Dependent Behavior

Using NLS parameters in SQL functions:

SELECT TO_CHAR(hire_date,'DD.Mon.YYYY','NLS_DATE_LANGUAGE=FRENCH')FROM employees

WHERE hire_date > '01-JAN-2000';

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Linguistic Searching and Sorting

Sort order can be affected by: Case-sensitivity

Diacritics or accent characters

Combination of characters that is treated as a single

character Phonetics or character appearance

Cultural preferences

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Linguistic Searching and Sorting

Three types of sorting: Binary sorting

Sorted according to the binary values of the encoded

characters

Monolingual linguistic sorting A two-pass sort based on a characters assigned major and

minor values

Multilingual linguistic sorting

Based on the ISO standard (ISO 14651), and the Unicode 3.2

Standard for multilingual collation Ordered by the number of strokes, PinYin, or radicals for

Chinese characters

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Using Linguistic Searching and Sorting

You can specify the type of sort used for character data withthe:

NLS_SORTparameter

Default value derived from the NLS_LANGenvironment

variable, if set

Can be specified for the session, client, or server

NLSSORTfunction

Defines the sorting method at the query level

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Case-Insensitive and Accent-Insensitive

Search and Sort

Specify the linguistic name:

Examples:

Specify the sort action for WHEREclauses and PL/SQL

blocks:

Useful for migrated databases

NLS_SORT = [_AI | _CI]

NLS_SORT = FRENCH_M_AI

NLS_SORT = XGERMAN_CI

NLS_COMP = BINARY | ANSI

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Support in SQL and Functions

The following SQL clauses support NLS_SORTandNLS_COMPsettings:

WHERE

ORDER BY

START WITH

HAVING

IN/NOT IN

BETWEEN

CASE-WHEN

The NLSSORT()function supports the case-insensitive andaccent-insensitive functionality.

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Linguistic Index Support

Create an index on linguistically sorted values. Rapidly query data without having to specify ORDER BY

clause and NLSSORT:

Set the NLS_SORTparameter to match the linguistic

definition that you want to use for the linguistic sort when

creating the index.

CREATE INDEX list_word ON

list (NLSSORT(word, 'NLS_SORT=French_M'));

SELECT word FROM list;

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Customizing Linguistic

Searching and Sorting

You can customize linguistic sorting for: Ignorable characters

Contracting or expanding characters

Special combination letters or special letters

Expanding characters or special letters Special uppercase and lowercase letters

Context-sensitive characters

Reverse secondary sorting

Canonical equivalence

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Implicit ConversionBetween CLOBandNCLOB

Transparent implicit conversion is supported in: SQL INand OUTbind variables for query and DML

PL/SQL functions and procedure parameter passing

PL/SQL variable assignment

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NLS Data Conversion with Oracle Utilities

Multiple data conversions can take place when data isexported from one database and imported into another if the

same character sets are not used.

External tables use the NLS settings on the server for

determining the data character set.

SQL*Loader:

Conventional path: Data is converted into the sessioncharacter set specified by NLS_LANG.

Direct path: Data is converted using client-side directives.

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NLS Data Conversion with Data Pump

Data Pump Export always saves data in the same characterset as the database from which the data originates.

Data Pump Import converts the data to the character set of

the target database, if needed.

The Data Pump log file is written in the language specifiedby NLS_LANGfor the session that started Data Pump.

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Language and Character Set File Scanner(LCSSCAN)

Character set

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Setting the Database Time Zone

The current time zone in the database is determined by thefollowing:

The SET TIME_ZONEclause of the CREATE DATABASE

statement

The time zone of the operating system on the databaseserver host

The time zone specified by the ALTER SESSION SETTIME_ZONEcommand

CREATE DATABASE ... SET TIME_ZONE='-04:00';

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Summary

In this lesson, you should have learned how to: Determine a correct database character set that meets your

business requirements

Obtain globalization support configuration information

Customize language-dependent behavior for the databaseand individual sessions

Specify different linguistic sorts for queries

Retrieve data that matches a search string ignoring case or

accent differences

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Practice 20 Overview:

Using Globalization Support

This practice covers the following topics: Determining the database character set

Setting the NLS_SORTvariable

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