20 Copyright © 2008, Oracle. All rights reserved. Globalization

Copyright © 2008, Oracle. All rights reserved 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 database and individual sessions Specify different linguistic sorts for queries Retrieve data that matches a search string ignoring case or accent differences

Copyright © 2008, Oracle. All rights reserved 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

Copyright © 2008, Oracle. All rights reserved 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

Copyright © 2008, Oracle. All rights reserved 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

Copyright © 2008, Oracle. All rights reserved Character Sets Full Notes Page

Copyright © 2008, Oracle. All rights reserved Understanding Unicode Supplementary characters AL32UTF8AL16UTF16 63 EEAA9E F09D849E 64 C3 D0A4 B6 á t d ö E A89E D834DD1E F c C Encoding: Representing characters with byte sequences

Copyright © 2008, Oracle. All rights reserved Understanding Unicode Encodings Full Notes Page

Copyright © 2008, Oracle. All rights reserved How Are Character Sets Used? Oracle Net compares the client NLS_LANG setting to the character set on the server. If needed, conversion occurs automatically and transparently. Client Oracle Net NLS_LANG Server

Copyright © 2008, Oracle. All rights reserved Problems to Avoid Example: No conversion occurs, because it does not seem to be required. Issue: Invalid data are entered into the database. Server Database character set: AL32UTF8 Client Windows English Code page: WE8MSWIN1252 NLS_LANG: AL32UTF8 Oracle Net

Copyright © 2008, Oracle. All rights reserved CREATE DATABASE... CHARACTER SET US7ASCII NATIONAL CHARACTER SET UTF8... % export NLS_LANG=‘SIMPLIFIED CHINESE_HONG KONG.ZHS16GBK’ Another Sample Problem

Copyright © 2008, Oracle. All rights reserved 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

Copyright © 2008, Oracle. All rights reserved Database Character Sets and National Character Sets Database Character SetsNational Character Sets Defined at creation time Cannot be changed without re-creation (exceptions in certain configurations) Can be exchanged Store data columns of type CHAR, VARCHAR2, CLOB, LONG Store data columns of type NCHAR, NVARCHAR2, NCLOB Can store varying-width character sets Can store Unicode using either AL16UTF16 or UTF8

Copyright © 2008, Oracle. All rights reserved Obtaining Character Set Information SQL> SELECT parameter, value 2 FROM nls_database_parameters 3 WHERE parameter LIKE '%CHARACTERSET%'; PARAMETER VALUE NLS_CHARACTERSET WE8ISO8859P1 NLS_NCHAR_CHARACTERSET AL16UTF16 2 rows selected.

Copyright © 2008, Oracle. All rights reserved SELECT sysdate FROM dual; Initialization parameters for the database server Environment variables for the clients ALTER SESSION command Specifying Language-Dependent Behavior SQL function

Copyright © 2008, Oracle. All rights reserved Specifying Language-Dependent Behavior for the Session Specify the locale behavior with the NLS_LANG environment variable: –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

Copyright © 2008, Oracle. All rights reserved Language-Dependent and Territory-Dependent Parameters ParameterDefault Values NLS_LANGUAGE NLS_DATE_LANGUAGE NLS_SORT AMERICAN BINARY NLS_TERRITORY NLS_CURRENCY NLS_DUAL_CURRENCY NLS_ISO_CURRENCY NLS_DATE_FORMAT NLS_NUMERIC_CHARACTERS NLS_TIMESTAMP_FORMAT NLS_TIMESTAMP_TZ_FORMAT AMERICA $ AMERICA DD-MON-RR., DD-MON-RRHH.MI.SSXFF AM DD-MON-RRHH.MI.SSXFF AM TZR

Copyright © 2008, Oracle. All rights reserved Language- and Territory-Dependent Parameters Full Notes Page

Copyright © 2008, Oracle. All rights reserved 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';

Copyright © 2008, Oracle. All rights reserved 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

Copyright © 2008, Oracle. All rights reserved 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 character’s 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

Copyright © 2008, Oracle. All rights reserved Using Linguistic Searching and Sorting You can specify the type of sort used for character data with the: NLS_SORT parameter –Default value derived from the NLS_LANG environment variable, if set –Can be specified for the session, client, or server NLSSORT function –Defines the sorting method at the query level

Copyright © 2008, Oracle. All rights reserved NLS Searching and Sorting Full Notes Page

Copyright © 2008, Oracle. All rights reserved Case-Insensitive and Accent-Insensitive Search and Sort Specify the linguistic name: Examples: Specify the sort action for WHERE clauses 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

Copyright © 2008, Oracle. All rights reserved Support in SQL and Functions The following SQL clauses support NLS_SORT and NLS_COMP settings: – WHERE – ORDER BY – START WITH – HAVING – IN/NOT IN – BETWEEN – CASE-WHEN The NLSSORT() function supports the case-insensitive and accent-insensitive functionality.

Copyright © 2008, Oracle. All rights reserved 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_SORT parameter 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;

Copyright © 2008, Oracle. All rights reserved 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

Copyright © 2008, Oracle. All rights reserved Customizing Linguistic Searching and Sorting Full Notes Page

Copyright © 2008, Oracle. All rights reserved Implicit Conversion Between CLOB and NCLOB Transparent implicit conversion is supported in: SQL IN and OUT bind variables for query and DML PL/SQL functions and procedure parameter passing PL/SQL variable assignment

Copyright © 2008, Oracle. All rights reserved NLS Data Conversion with Oracle Utilities Multiple data conversions can take place when data is exported 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 session character set specified by NLS_LANG. –Direct path: Data is converted using client-side directives.

Copyright © 2008, Oracle. All rights reserved NLS Data Conversion with Oracle Utilities Full Notes Page

Copyright © 2008, Oracle. All rights reserved NLS Data Conversion with Data Pump Data Pump Export always saves data in the same character set 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 specified by NLS_LANG for the session that started Data Pump.

Copyright © 2008, Oracle. All rights reserved Language and Character Set File Scanner ( LCSSCAN ) Character set

Copyright © 2008, Oracle. All rights reserved Setting the Database Time Zone The current time zone in the database is determined by the following: The SET TIME_ZONE clause of the CREATE DATABASE statement The time zone of the operating system on the database server host The time zone specified by the ALTER SESSION SET TIME_ZONE command CREATE DATABASE... SET TIME_ZONE='-04:00';

Copyright © 2008, Oracle. All rights reserved 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 database and individual sessions Specify different linguistic sorts for queries Retrieve data that matches a search string ignoring case or accent differences

Copyright © 2008, Oracle. All rights reserved Practice 20 Overview: Using Globalization Support This practice covers the following topics: Determining the database character set Setting the NLS_SORT variable