Setting up the Globalization Support Environment

NLS_LANGUAGE

The NLS_LANGUAGE parameter can be set to any valid language name and the default is derived from the NLS_LANG setting. NLS_LANGUAGE specifies the default conventions for the following session characteristics:

• Language for server messages

• Language for day and month names and their abbreviations (specified in the SQL functions TO_CHAR and TO_DATE)

• Symbols for equivalents of AM, PM, AD, and BC.

• Default sorting sequence for character data when ORDER BY is specified. (GROUP BY uses a binary sort unless ORDER BY is specified.)

Example: NLS_LANGUAGE=ITALIAN and Example: NLS_LANGUAGE=GERMAN show the results from setting NLS_LANGUAGE to different values. In Example: NLS_LANGUAGE=ITALIAN, the ALTER SESSION statement is issued to set NLS_LANGUAGE to Italian.

ALTER SESSION SET NLS_LANGUAGE=Italian;

-- enter a SELECT to check the format of the output after the ALTER SESSION
SELECT last_name, hire_date, ROUND(salary/8,2) salary FROM employees 
  WHERE employee_id IN (111, 112, 113);

You should see results similar to the following:

Note that the month name abbreviations are in Italian.

In Example: NLS_LANGUAGE=GERMAN, the ALTER SESSION statement is issued to change the language to German.

ALTER SESSION SET NLS_LANGUAGE=German;

SELECT last_name, hire_date, ROUND(salary/8,2) salary FROM employees
    WHERE employee_id IN (111, 112, 113);

You should see results similar to the following:

Note that the language of the month abbreviations has changed to German.

NLS_TERRITORY

The NLS_TERRITORY parameter can be set to any valid territory name and the default is derived from the NLS_LANG setting. NLS_TERRITORY specifies the conventions for the following default date and numeric formatting characteristics:

• Date format

• Decimal character and group separator

• Local currency symbol

• ISO currency symbol

• Dual currency symbol

The territory can be modified dynamically during the session by specifying the new NLS_TERRITORY value in an ALTER SESSION statement. For example, to change the territory to France during a session, issue the following ALTER SESSION statement:

ALTER SESSION SET NLS_TERRITORY = France;

Modifying NLS_TERRITORY resets all derived NLS session parameters to default values for the new territory. Example: NLS_LANGUAGE=AMERICAN, NLS_TERRITORY=AMERICA and Example: NLS_LANGUAGE=AMERICAN, NLS_TERRITORY=GERMANY show behavior that results from different settings of NLS_TERRITORY and NLS_LANGUAGE.

-- set NLS_LANAGUAGE and NLS_TERRITORY
ALTER SESSION SET NLS_LANGUAGE = American NLS_TERRITORY = America;

-- enter the following SELECT to view the format of the output for currency
SELECT TO_CHAR(salary,'L99G999D99') salary FROM employees
     WHERE employee_id IN (100, 101, 102);

When NLS_TERRITORY is set to AMERICA and NLS_LANGUAGE is set to AMERICAN, results similar to the following should appear:

In Example: NLS_LANGUAGE=AMERICAN, NLS_TERRITORY=GERMANY an ALTER SESSION statement is issued to change the territory to Germany.

-- set NLS_TERRITORY to Germany for this session
ALTER SESSION SET NLS_TERRITORY = Germany;

SELECT TO_CHAR(salary,'L99G999D99') salary FROM employees
    WHERE employee_id IN (100, 101, 102);

You should see results similar to the following:

Note that the currency symbol has changed from $ to €. The numbers have not changed because the underlying data is the same.

Date Formats

Different date formats are shown in Table: Examples of Short Date Formats.

This topic includes the following parameters:

• NLS_DATE_FORMAT

• NLS_DATE_LANGUAGE

-- Use an ALTER SESSION statement to change the territory to America, 
-- and the language to American
ALTER SESSION SET NLS_TERRITORY = America NLS_LANGUAGE = American;

-- After the session is altered, select the dates with the format masks
SELECT hire_date, TO_CHAR(hire_date,'DS') "Short", 
  TO_CHAR(hire_date,'DL') "Long" FROM employees
  WHERE employee_id IN (111, 112, 113);

-- set NLS_DATE_LANAGUAGE for this user session
ALTER SESSION SET NLS_DATE_LANGUAGE = FRENCH;

-- display the current system date
SELECT TO_CHAR(SYSDATE, 'Day:Dd Month yyyy') FROM DUAL;

Time Formats

Different time formats are shown in Table: Examples of Time Formats.

This topic contains information about the following parameters:

• NLS_TIMESTAMP_FORMAT

• NLS_TIMESTAMP_TZ_FORMAT

-- display August 20, 2005 using the format of NLS_TIMPSTAMP_TZ_FORMAT
SELECT TO_TIMESTAMP_TZ('2005-08-20, 05:00:00.55 America/Los_Angeles', 
  'yyyy-mm-dd hh:mi:ss.ff TZR') "TIMESTAMP_TZ Format" FROM DUAL;

Calendar Formats

The following calendar information is stored for each territory:

• First Day of the Week

• First Calendar Week of the Year

• Number of Days and Months in a Year

• First Year of Era

NLS_CALENDAR

Many different calendar systems are in use throughout the world. NLS_CALENDAR specifies which calendar system Oracle uses. The default value is Gregorian. The value can be any valid calendar format name.

NLS_CALENDAR can have one of the following values:

• Arabic Hijrah

• English Hijrah

• Gregorian

• Japanese Imperial

• Persian

• ROC Official (Republic of China)

• Thai Buddha

In Example: NLS_CALENDAR='English Hijrah' NLS_CALENDAR is set to English Hijrah.

-- set NLS_CALENDAR with ALTER SESSION
ALTER SESSION SET NLS_CALENDAR='English Hijrah';

-- display the current system date
SELECT SYSDATE FROM DUAL;

You should see output similar to the following, depending on the current system date:

Numeric Formats

The database must know the number-formatting convention used in each session to interpret numeric strings correctly. For example, the database needs to know whether numbers are entered with a period or a comma as the decimal character (234.00 or 234,00). Similarly, applications must be able to display numeric information in the format expected at the client site.

Examples of numeric formats are shown in Table: Examples of Numeric Formats.

Numeric formats are derived from the setting of the NLS_TERRITORY parameter, but they can be overridden by the NLS_NUMERIC_CHARACTERS parameter.

NLS_NUMERIC_CHARACTERS

The NLS_NUMERIC_CHARACTERS parameter specifies the decimal character and group separator. The group separator is the character that separates integer groups to show thousands and millions, for example. The group separator is the character returned by the G number format mask. The decimal character separates the integer and decimal parts of a number. Setting NLS_NUMERIC_CHARACTERS overrides the default values derived from the setting of NLS_TERRITORY. The value can be any two valid numeric characters for the decimal character and group separator.

Any character can be the decimal character or group separator. The two characters specified must be single-byte, and the characters must be different from each other. The characters cannot be any numeric character or any of the following characters: plus (+), hyphen (-), less than sign (<), greater than sign (>). Either character can be a space.

To set the decimal character to a comma and the grouping separator to a period, define NLS_NUMERIC_CHARACTERS as follows:

ALTER SESSION SET NLS_NUMERIC_CHARACTERS = ",.";

SQL statements can include numbers represented as numeric or text literals. Numeric literals are not enclosed in quotes. They are part of the SQL language syntax and always use a dot as the decimal character and never contain a group separator. Text literals are enclosed in single quotes. They are implicitly or explicitly converted to numbers, if required, according to the current NLS settings.

The following SELECT statement formats the number 4000 with the decimal character and group separator specified in the ALTER SESSION statement:

ALTER SESSION SET NLS_NUMERIC_CHARACTERS = ",.";
SELECT TO_CHAR(4000, '9G999D99') FROM DUAL;

You should see output similar to the following:

Currency Formats

Different currency formats are used throughout the world. Some typical ones are shown in Table: Currency Format Examples.

NLS_CURRENCY

NLS_CURRENCY specifies the character string returned by the L number format mask, the local currency symbol. Setting NLS_CURRENCY overrides the default setting defined implicitly by NLS_TERRITORY. The value can be any valid currency symbol string.

-- select and format the salary column from employees
SELECT TO_CHAR(salary, 'L099G999D99') "salary" FROM employees 
  WHERE salary > 11000;

You should see output similar to the following:

NLS_ISO_CURRENCY

NLS_ISO_CURRENCY specifies the character string returned by the C number format mask, the ISO currency symbol. Setting NLS_ISO_CURRENCY overrides the default value defined implicitly by NLS_TERRITORY. The value can be any valid string.

Local currency symbols can be ambiguous. For example, a dollar sign ($) can refer to US dollars or Australian dollars. ISO specifications define unique currency symbols for specific territories or countries. For example, the ISO currency symbol for the US dollar is USD. The ISO currency symbol for the Australian dollar is AUD.

NLS_ISO_CURRENCY has the same syntax as the NLS_TERRITORY parameter, and all supported territories are valid values.

To specify the ISO currency symbol for France, set NLS_ISO_CURRENCY as shown in Example: Setting NLS_ISO_CURRENCY.

-- set NLS_ISO_CURRENCY to France
ALTER SESSION SET NLS_ISO_CURRENCY = FRANCE;

-- display the salary of selected employees
SELECT TO_CHAR(salary, 'C099G999D99') "Salary" FROM employees
  WHERE department_id = 60;

You should see output similar to the following:

NLS_DUAL_CURRENCY

Use NLS_DUAL_CURRENCY to override the default dual currency symbol defined implicitly by NLS_TERRITORY. The value can be any valid symbol.

NLS_DUAL_CURRENCY was introduced to support the euro currency symbol during the euro transition period.

NLS_SORT

The NLS_SORT parameter specifies the collating sequence for ORDER BY queries. It overrides the default NLS_SORT value that is derived from NLS_LANGUAGE. The value of NLS_SORT can be BINARY or any valid linguistic sort name:

NLS_SORT = BINARY | sort_name

If the value is BINARY, then the collating sequence is based on the numeric code of the characters in the underlying encoding scheme. Depending on the data type, this will either be in the binary sequence order of the database character set or the national character set. If the value is a named linguistic sort, sorting is based on the order of the defined sort. Most, but not all, languages supported by the NLS_LANGUAGE parameter also support a linguistic sort with the same name.

You can set the NLS_SORT parameter to change the linguistic sorting behavior of the your SQL session. Spain traditionally treats ch, ll as well as ñ as letters of their own, ordered after c, l and n respectively. Example: Setting NLS_SORT to BINARY and Example: Setting NLS_SORT to Spanish illustrate the effect of using a Spanish sort against the employee names Chen and Chung. In Example: Setting NLS_SORT to BINARY, the NLS_SORT parameter is set to BINARY.

In Example: Setting NLS_SORT to BINARY, LIKE is used to specify the records to return with the query. For information on LIKE, see Restricting Data Using the WHERE Clause.

-- set the NLS_SORT for this user session
ALTER SESSION SET NLS_SORT=binary;

-- select the last name of those employees whose last name begin with C
SELECT last_name FROM employees
   WHERE last_name LIKE 'C%' ORDER BY last_name;

The output of Example: Setting NLS_SORT to BINARY appears:

In Example: Setting NLS_SORT to Spanish, the NLS_SORT parameter is set to SPANISH_M.

-- set the NLS_SORT for this user session
ALTER SESSION SET NLS_SORT=spanish_m;

-- select the last name of those employees whose last name begin with C
SELECT last_name FROM employees 
   WHERE last_name LIKE 'C%' ORDER BY last_name;

The output of Example: Setting NLS_SORT to Spanish appears:

Note that the order of last names in the output from the SELECT statement in Example: Setting NLS_SORT to BINARY and Example: Setting NLS_SORT to Spanish is different.

NLS_COMP

When using comparison operators, characters are compared according to their binary codes in the designated encoding scheme. A character is greater than another if it has a higher binary code. Because the binary sequence of characters may not match the linguistic sequence for a particular language, such comparisons might not be linguistically correct.

The value of the NLS_COMP parameter affects the comparison behavior of SQL operations. The value can be BINARY (default) or LINGUISTIC. You can use NLS_COMP to avoid the cumbersome process of using the NLSSORT function in SQL statements when you want to perform a linguistic comparison instead of a binary comparison. When NLS_COMP is set to LINGUISTIC, SQL operations perform a linguistic comparison based on the value of NLS_SORT.

Example: Setting NLS_COMP to BINARY and Example: Setting NLS_COMP to BINARY illustrate the effect of performing a binary comparison follow by a Spanish linguistic sensitive comparison against the employee names. In Example: Setting NLS_COMP to BINARY the NLS_COMP parameter is set to BINARY while NLS_SORT is set to Spanish.

-- set NLS_SORT and NLS_COMP for this user session
ALTER SESSION SET NLS_SORT=spanish_m NLS_COMP=binary;

-- select the last name of those employees whose last name begin with C
SELECT last_name FROM employees 
  WHERE last_name LIKE 'C%';

The output of Example: Setting NLS_COMP to BINARY appears:

In Example: Setting NLS_COMP to BINARY the NLS_COMP parameter is set to LINGUISTIC while NLS_SORT is set to Spanish.

-- set NLS_SORT and NLS_COMP for this user session
ALTER SESSION SET NLS_SORT=spanish_m NLS_COMP=linguistic;

-- select the last name of those employees whose last name begin with C
SELECT last_name FROM employees 
  WHERE last_name LIKE 'C%';

The output of Example: Setting NLS_COMP to BINARY appears:

Note the difference in the output of Example: Setting NLS_COMP to BINARY and Example: Setting NLS_COMP to BINARY. In Spanish ch is treated as a separate character following c so ch is excluded when a Spanish linguistic sensitive comparison is performed in Example: Setting NLS_COMP to BINARY.

Case and Accent Insensitive Searching

Operations inside a database are sensitive to the case and the accents of the characters. Sometimes you might need to perform case-insensitive or accent-insensitive comparisons. Use the NLS_SORT session parameter to specify a case-insensitive or accent insensitive sort.

To specify a case-insensitive or accent-insensitive sort:

• Append _CI to an Oracle sort name for a case-insensitive sort. For example:

  BINARY_CI: accent sensitive and case insensitive binary sort

  GENERIC_M_CI: accent sensitive and case insensitive GENERIC_M sort

• Append _AI to an Oracle sort name for an accent-insensitive and case-insensitive sort. For example:

  BINARY_AI: accent insensitive and case insensitive binary sort

  FRENCH_M_AI: accent insensitive and case insensitive FRENCH_M sort

NLS_LENGTH_SEMANTICS

The NLS_LENGTH_SEMANTICS parameter specifies BYTE (default) or CHAR semantics. By default, the character data types CHAR and VARCHAR2 are specified in bytes, not characters. Hence, the specification CHAR(20) in a table definition allows 20 bytes for storing character data.

NLS_LENGTH_SEMANTICS enables you to create CHAR, VARCHAR2, and LONG columns using either byte or character length semantics. NCHAR, NVARCHAR2, CLOB, and NCLOB columns are always character-based. Existing columns are not affected.

Example: Length Semantics and CREATE TABLE shows an example of creating a table. When the database character set is WE8MSWIN1252, the last_name column of the table can hold up to 10 Western European characters, occupying a maximum of 10 bytes. When the database character set is Unicode (AL32UTF8), last_name can still hold up to 10 Unicode characters regardless of the language; however, it can occupy a maximum of 40 bytes.

CREATE TABLE temp_employees_table
( employee_id NUMBER(4), last_name VARCHAR2(10 CHAR), job_id VARCHAR2(9), 
  manager_id NUMBER(4), hire_date DATE, salary NUMBER(7,2), 
  department_id NUMBER(2)) ;