Skip Headers
Oracle® Database SQL Language Reference
11g Release 1 (11.1)

B28286-07
Go to Documentation Home
Home
Go to Book List
Book List
Go to Table of Contents
Contents
Go to Index
Index
Go to Master Index
Master Index
Go to Feedback page
Contact Us

Go to previous page
Previous
Go to next page
Next
PDF · Mobi · ePub

Format Models

A format model is a character literal that describes the format of datetime or numeric data stored in a character string. A format model does not change the internal representation of the value in the database. When you convert a character string into a date or number, a format model determines how Oracle Database interprets the string. In SQL statements, you can use a format model as an argument of the TO_CHAR and TO_DATE functions to specify:

For example:

For lists of number and datetime format model elements, see Table 2-13, "Number Format Elements" and Table 2-15, "Datetime Format Elements".

The values of some formats are determined by the value of initialization parameters. For such formats, you can specify the characters returned by these format elements implicitly using the initialization parameter NLS_TERRITORY. You can change the default date format for your session with the ALTER SESSION statement.

See Also:

This remainder of this section describes how to use the following format models:

Number Format Models

You can use number format models in the following functions:

  • In the TO_CHAR function to translate a value of NUMBER, BINARY_FLOAT, or BINARY_DOUBLE datatype to VARCHAR2 datatype

  • In the TO_NUMBER function to translate a value of CHAR or VARCHAR2 datatype to NUMBER datatype

  • In the TO_BINARY_FLOAT and TO_BINARY_DOUBLE functions to translate CHAR and VARCHAR2 expressions to BINARY_FLOAT or BINARY_DOUBLE values

All number format models cause the number to be rounded to the specified number of significant digits. If a value has more significant digits to the left of the decimal place than are specified in the format, then pound signs (#) replace the value. This event typically occurs when you are using TO_CHAR with a restrictive number format string, causing a rounding operation.

  • If a positive NUMBER value is extremely large and cannot be represented in the specified format, then the infinity sign (~) replaces the value. Likewise, if a negative NUMBER value is extremely small and cannot be represented by the specified format, then the negative infinity sign replaces the value (-~).

  • If a BINARY_FLOAT or BINARY_DOUBLE value is converted to CHAR or NCHAR, and the input is either infinity or NaN (not a number), then Oracle always returns the pound signs to replace the value. However, if you omit the format model, then Oracle returns either Inf or Nan as a string.

Number Format Elements

A number format model is composed of one or more number format elements. The tables that follow list the elements of a number format model and provide some examples.

Negative return values automatically contain a leading negative sign and positive values automatically contain a leading space unless the format model contains the MI, S, or PR format element.

Table 2-13 Number Format Elements

Element Example Description

, (comma)

9,999

Returns a comma in the specified position. You can specify multiple commas in a number format model.

Restrictions:

  • A comma element cannot begin a number format model.

  • A comma cannot appear to the right of a decimal character or period in a number format model.

. (period)

99.99

Returns a decimal point, which is a period (.) in the specified position.

Restriction: You can specify only one period in a number format model.

$

$9999

Returns value with a leading dollar sign.

0

0999

9990

Returns leading zeros.

Returns trailing zeros.

9

9999

Returns value with the specified number of digits with a leading space if positive or with a leading minus if negative. Leading zeros are blank, except for a zero value, which returns a zero for the integer part of the fixed-point number.

B

B9999

Returns blanks for the integer part of a fixed-point number when the integer part is zero (regardless of zeros in the format model).

C

C999

Returns in the specified position the ISO currency symbol (the current value of the NLS_ISO_CURRENCY parameter).

D

99D99

Returns in the specified position the decimal character, which is the current value of the NLS_NUMERIC_CHARACTER parameter. The default is a period (.).

Restriction: You can specify only one decimal character in a number format model.

EEEE

9.9EEEE

Returns a value using in scientific notation.

G

9G999

Returns in the specified position the group separator (the current value of the NLS_NUMERIC_CHARACTER parameter). You can specify multiple group separators in a number format model.

Restriction: A group separator cannot appear to the right of a decimal character or period in a number format model.

L

L999

Returns in the specified position the local currency symbol (the current value of the NLS_CURRENCY parameter).

MI

9999MI

Returns negative value with a trailing minus sign (-).

Returns positive value with a trailing blank.

Restriction: The MI format element can appear only in the last position of a number format model.

PR

9999PR

Returns negative value in <angle brackets>.

Returns positive value with a leading and trailing blank.

Restriction: The PR format element can appear only in the last position of a number format model.

RN

rn

RN

rn

Returns a value as Roman numerals in uppercase.

Returns a value as Roman numerals in lowercase.

Value can be an integer between 1 and 3999.

S

S9999

9999S

Returns negative value with a leading minus sign (-).

Returns positive value with a leading plus sign (+).

Returns negative value with a trailing minus sign (-).

Returns positive value with a trailing plus sign (+).

Restriction: The S format element can appear only in the first or last position of a number format model.

TM

TM

The text minimum number format model returns (in decimal output) the smallest number of characters possible. This element is case insensitive.

The default is TM9, which returns the number in fixed notation unless the output exceeds 64 characters. If the output exceeds 64 characters, then Oracle Database automatically returns the number in scientific notation.

Restrictions:

  • You cannot precede this element with any other element.

  • You can follow this element only with one 9 or one E (or e), but not with any combination of these. The following statement returns an error:

    SELECT TO_CHAR(1234, 'TM9e') FROM DUAL;

U

U9999

Returns in the specified position the Euro (or other) dual currency symbol, determined by the current value of the NLS_DUAL_CURRENCY parameter.

V

999V99

Returns a value multiplied by 10n (and if necessary, round it up), where n is the number of 9's after the V.

X

XXXX

xxxx

Returns the hexadecimal value of the specified number of digits. If the specified number is not an integer, then Oracle Database rounds it to an integer.

Restrictions:

  • This element accepts only positive values or 0. Negative values return an error.

  • You can precede this element only with 0 (which returns leading zeroes) or FM. Any other elements return an error. If you specify neither 0 nor FM with X, then the return always has one leading blank.


Table 2-14 shows the results of the following query for different values of number and 'fmt':

SELECT TO_CHAR(number, 'fmt')
   FROM DUAL;

Table 2-14 Results of Number Conversions

number 'fmt' Result

-1234567890

9999999999S

'1234567890-'

0

99.99

' .00'

+0.1

99.99

' .10'

-0.2

99.99

' -.20'

0

90.99

' 0.00'

+0.1

90.99

' 0.10'

-0.2

90.99

' -0.20'

0

9999

' 0'

1

9999

' 1'

0

B9999

' '

1

B9999

' 1'

0

B90.99

' '

+123.456

999.999

' 123.456'

-123.456

999.999

'-123.456'

+123.456

FM999.009

'123.456'

+123.456

9.9EEEE

' 1.2E+02'

+1E+123

9.9EEEE

' 1.0E+123'

+123.456

FM9.9EEEE

'1.2E+02'

+123.45

FM999.009

'123.45'

+123.0

FM999.009

'123.00'

+123.45

L999.99

' $123.45'

+123.45

FML999.99

'$123.45'

+1234567890

9999999999S

'1234567890+'


Datetime Format Models

You can use datetime format models in the following functions:

  • In the TO_* datetime functions to translate a character value that is in a format other than the default format into a datetime value. (The TO_* datetime functions are TO_DATE, TO_TIMESTAMP, and TO_TIMESTAMP_TZ.)

  • In the TO_CHAR function to translate a datetime value into a character value that is in a format other than the default format (for example, to print the date from an application)

The total length of a datetime format model cannot exceed 22 characters.

The default datetime formats are specified either explicitly with the NLS session parameters NLS_DATE_FORMAT, NLS_TIMESTAMP_FORMAT, and NLS_TIMESTAMP_TZ_FORMAT, or implicitly with the NLS session parameter NLS_TERRITORY. You can change the default datetime formats for your session with the ALTER SESSION statement.

See Also:

ALTER SESSION and Oracle Database Globalization Support Guide for information on the NLS parameters

Datetime Format Elements

A datetime format model is composed of one or more datetime format elements as listed in Table 2-15, "Datetime Format Elements".

  • For input format models, format items cannot appear twice, and format items that represent similar information cannot be combined. For example, you cannot use 'SYYYY' and 'BC' in the same format string.

  • The second column indicates whether the format element can be used in the TO_* datetime functions. All format elements can be used in the TO_CHAR function.

  • The following datetime format elements can be used in timestamp and interval format models, but not in the original DATE format model: FF, TZD, TZH, TZM, and TZR.

  • Many datetime format elements are padded with blanks or leading zeroes to a specific length. Refer to the format model modifier FM for more information.

Uppercase Letters in Date Format Elements

Capitalization in a spelled-out word, abbreviation, or Roman numeral follows capitalization in the corresponding format element. For example, the date format model 'DAY' produces capitalized words like 'MONDAY'; 'Day' produces 'Monday'; and 'day' produces 'monday'.

Punctuation and Character Literals in Datetime Format Models

You can include these characters in a date format model:

  • Punctuation such as hyphens, slashes, commas, periods, and colons

  • Character literals, enclosed in double quotation marks

These characters appear in the return value in the same location as they appear in the format model.

Table 2-15 Datetime Format Elements

Element TO_* datetime functions? Description
-
/
,
.
;
:
"text"

Yes

Punctuation and quoted text is reproduced in the result.

AD
A.D.

Yes

AD indicator with or without periods.

AM
A.M.

Yes

Meridian indicator with or without periods.

BC
B.C.

Yes

BC indicator with or without periods.

CC
SCC
 

Century.

  • If the last 2 digits of a 4-digit year are between 01 and 99 (inclusive), then the century is one greater than the first 2 digits of that year.

  • If the last 2 digits of a 4-digit year are 00, then the century is the same as the first 2 digits of that year.

For example, 2002 returns 21; 2000 returns 20.

D

Yes

Day of week (1-7).

DAY

Yes

Name of day.

DD

Yes

Day of month (1-31).

DDD

Yes

Day of year (1-366).

DL

Yes

Returns a value in the long date format, which is an extension of Oracle Database's DATE format, determined by the current value of the NLS_DATE_FORMAT parameter. Makes the appearance of the date components (day name, month number, and so forth) depend on the NLS_TERRITORY and NLS_LANGUAGE parameters. For example, in the AMERICAN_AMERICA locale, this is equivalent to specifying the format 'fmDay, Month dd, yyyy'. In the GERMAN_GERMANY locale, it is equivalent to specifying the format 'fmDay, dd. Month yyyy'.

Restriction: You can specify this format only with the TS element, separated by white space.

DS

Yes

Returns a value in the short date format. Makes the appearance of the date components (day name, month number, and so forth) depend on the NLS_TERRITORY and NLS_LANGUAGE parameters. For example, in the AMERICAN_AMERICA locale, this is equivalent to specifying the format 'MM/DD/RRRR'. In the ENGLISH_UNITED_KINGDOM locale, it is equivalent to specifying the format 'DD/MM/RRRR'.

Restriction: You can specify this format only with the TS element, separated by white space.

DY

Yes

Abbreviated name of day.

E

Yes

Abbreviated era name (Japanese Imperial, ROC Official, and Thai Buddha calendars).

EE

Yes

Full era name (Japanese Imperial, ROC Official, and Thai Buddha calendars).

FF [1..9]

Yes

Fractional seconds; no radix character is printed. Use the X format element to add the radix character. Use the numbers 1 to 9 after FF to specify the number of digits in the fractional second portion of the datetime value returned. If you do not specify a digit, then Oracle Database uses the precision specified for the datetime datatype or the datatype's default precision. Valid in timestamp and interval formats, but not in DATE formats.

Examples: 'HH:MI:SS.FF'

SELECT TO_CHAR(SYSTIMESTAMP, 'SS.FF3') from dual;

FM

Yes

Returns a value with no leading or trailing blanks.

See Also: Additional discussion on this format model modifier in the Oracle Database SQL Language Reference

FX

Yes

Requires exact matching between the character data and the format model.

See Also: Additional discussion on this format model modifier in the Oracle Database SQL Language Reference

HH
HH12

Yes

Hour of day (1-12).

HH24

Yes

Hour of day (0-23).

IW
 

Week of year (1-52 or 1-53) based on the ISO standard.

IYY
IY
I
 

Last 3, 2, or 1 digit(s) of ISO year.

IYYY
 

4-digit year based on the ISO standard.

J

Yes

Julian day; the number of days since January 1, 4712 BC. Number specified with J must be integers.

MI

Yes

Minute (0-59).

MM

Yes

Month (01-12; January = 01).

MON

Yes

Abbreviated name of month.

MONTH

Yes

Name of month.

PM
P.M.

Yes

Meridian indicator with or without periods.

Q
 

Quarter of year (1, 2, 3, 4; January - March = 1).

RM

Yes

Roman numeral month (I-XII; January = I).

RR

Yes

Lets you store 20th century dates in the 21st century using only two digits.

See Also: Additional discussion on RR datetime format element in the Oracle Database SQL Language Reference

RRRR

Yes

Round year. Accepts either 4-digit or 2-digit input. If 2-digit, provides the same return as RR. If you do not want this functionality, then enter the 4-digit year.

SS

Yes

Second (0-59).

SSSSS

Yes

Seconds past midnight (0-86399).

TS

Yes

Returns a value in the short time format. Makes the appearance of the time components (hour, minutes, and so forth) depend on the NLS_TERRITORY and NLS_LANGUAGE initialization parameters.

Restriction: You can specify this format only with the DL or DS element, separated by white space.

TZD 

Yes

Daylight savings information. The TZD value is an abbreviated time zone string with daylight saving information. It must correspond with the region specified in TZR. Valid in timestamp and interval formats, but not in DATE formats.

Example: PST (for US/Pacific standard time); PDT (for US/Pacific daylight time).

TZH

Yes

Time zone hour. (See TZM format element.) Valid in timestamp and interval formats, but not in DATE formats.

Example: 'HH:MI:SS.FFTZH:TZM'.

TZM

Yes

Time zone minute. (See TZH format element.) Valid in timestamp and interval formats, but not in DATE formats.

Example: 'HH:MI:SS.FFTZH:TZM'.

TZR

Yes

Time zone region information. The value must be one of the time zone regions supported in the database. Valid in timestamp and interval formats, but not in DATE formats.

Example: US/Pacific

WW
 

Week of year (1-53) where week 1 starts on the first day of the year and continues to the seventh day of the year.

W
 

Week of month (1-5) where week 1 starts on the first day of the month and ends on the seventh.

X

Yes

Local radix character.

Example: 'HH:MI:SSXFF'.

Y,YYY

Yes

Year with comma in this position.

YEAR
SYEAR
 

Year, spelled out; S prefixes BC dates with a minus sign (-).

YYYY
SYYYY

Yes

4-digit year; S prefixes BC dates with a minus sign.

YYY
YY
Y

Yes

Last 3, 2, or 1 digit(s) of year.


Oracle Database converts strings to dates with some flexibility. For example, when the TO_DATE function is used, a format model containing punctuation characters matches an input string lacking some or all of these characters, provided each numerical element in the input string contains the maximum allowed number of digits—for example, two digits '05' for 'MM' or four digits '2007' for 'YYYY'. The following statement does not return an error:

SELECT TO_CHAR (TO_DATE('0297','MM/YY'), 'MM/YY') FROM DUAL;

TO_CH
-----
02/07
 

However, the following format string does return an error, because the FX (format exact) format modifier requires an exact match of the expression and the format string:

SELECT TO_CHAR(TO_DATE('0207', 'fxmm/yy'), 'mm/yy') FROM DUAL;
SELECT TO_CHAR(TO_DATE('0207', 'fxmm/yy'), 'mm/yy') FROM DUAL
                       *
ERROR at line 1:
ORA-01861: literal does not match format string

Datetime Format Elements and Globalization Support

The functionality of some datetime format elements depends on the country and language in which you are using Oracle Database. For example, these datetime format elements return spelled values:

  • MONTH

  • MON

  • DAY

  • DY

  • BC or AD or B.C. or A.D.

  • AM or PM or A.M or P.M.

The language in which these values are returned is specified either explicitly with the initialization parameter NLS_DATE_LANGUAGE or implicitly with the initialization parameter NLS_LANGUAGE. The values returned by the YEAR and SYEAR datetime format elements are always in English.

The datetime format element D returns the number of the day of the week (1-7). The day of the week that is numbered 1 is specified implicitly by the initialization parameter NLS_TERRITORY.

See Also:

Oracle Database Reference and Oracle Database Globalization Support Guide for information on globalization support initialization parameters

ISO Standard Date Format Elements

Oracle calculates the values returned by the datetime format elements IYYY, IYY, IY, I, and IW according to the ISO standard. For information on the differences between these values and those returned by the datetime format elements YYYY, YYY, YY, Y, and WW, see the discussion of globalization support in Oracle Database Globalization Support Guide.

The RR Datetime Format Element

The RR datetime format element is similar to the YY datetime format element, but it provides additional flexibility for storing date values in other centuries. The RR datetime format element lets you store 20th century dates in the 21st century by specifying only the last two digits of the year.

If you use the TO_DATE function with the YY datetime format element, then the year returned always has the same first 2 digits as the current year. If you use the RR datetime format element instead, then the century of the return value varies according to the specified two-digit year and the last two digits of the current year.

That is:

  • If the specified two-digit year is 00 to 49, then

    • If the last two digits of the current year are 00 to 49, then the returned year has the same first two digits as the current year.

    • If the last two digits of the current year are 50 to 99, then the first 2 digits of the returned year are 1 greater than the first 2 digits of the current year.

  • If the specified two-digit year is 50 to 99, then

    • If the last two digits of the current year are 00 to 49, then the first 2 digits of the returned year are 1 less than the first 2 digits of the current year.

    • If the last two digits of the current year are 50 to 99, then the returned year has the same first two digits as the current year.

The following examples demonstrate the behavior of the RR datetime format element.

RR Datetime Format Examples

Assume these queries are issued between 1950 and 1999:

SELECT TO_CHAR(TO_DATE('27-OCT-98', 'DD-MON-RR') ,'YYYY') "Year"
   FROM DUAL;

Year
----
1998

SELECT TO_CHAR(TO_DATE('27-OCT-17', 'DD-MON-RR') ,'YYYY') "Year"
   FROM DUAL; 

Year
----
2017

Now assume these queries are issued between 2000 and 2049:

SELECT TO_CHAR(TO_DATE('27-OCT-98', 'DD-MON-RR') ,'YYYY') "Year"
   FROM DUAL; 

Year
----
1998 

SELECT TO_CHAR(TO_DATE('27-OCT-17', 'DD-MON-RR') ,'YYYY') "Year"
   FROM DUAL; 

Year
----
2017

Note that the queries return the same values regardless of whether they are issued before or after the year 2000. The RR datetime format element lets you write SQL statements that will return the same values from years whose first two digits are different.

Datetime Format Element Suffixes

Table 2-16 lists suffixes that can be added to datetime format elements:

Table 2-16 Date Format Element Suffixes

Suffix Meaning Example Element Example Value

TH

Ordinal Number

DDTH

4TH

SP

Spelled Number

DDSP

FOUR

SPTH or THSP

Spelled, ordinal number

DDSPTH

FOURTH


Notes on date format element suffixes:

  • When you add one of these suffixes to a datetime format element, the return value is always in English.

  • Datetime suffixes are valid only to format output. You cannot use them to insert a date into the database.

Format Model Modifiers

The FM and FX modifiers, used in format models in the TO_CHAR function, control blank padding and exact format checking.

A modifier can appear in a format model more than once. In such a case, each subsequent occurrence toggles the effects of the modifier. Its effects are enabled for the portion of the model following its first occurrence, and then disabled for the portion following its second, and then reenabled for the portion following its third, and so on.

FM Fill mode. Oracle uses trailing blank characters and leading zeroes to fill format elements to a constant width. The width is equal to the display width of the largest element for the relevant format model:

  • Numeric elements are padded with leading zeros to the width of the maximum value allowed for the element. For example, the YYYY element is padded to four digits (the length of '9999'), HH24 to two digits (the length of '23'), and DDD to three digits (the length of '366').

  • The character elements MONTH, MON, DAY, and DY are padded with trailing blanks to the width of the longest full month name, the longest abbreviated month name, the longest full date name, or the longest abbreviated day name, respectively, among valid names determined by the values of NLS_DATE_LANGUAGE and NLS_CALENDAR parameters. For example, when NLS_DATE_LANGUAGE is AMERICAN and NLS_CALENDAR is GREGORIAN (the default), the largest element for MONTH is SEPTEMBER, so all values of the MONTH format element are padded to nine display characters. The values of the NLS_DATE_LANGUAGE and NLS_CALENDAR parameters are specified in the third argument to TO_CHAR and TO_* datetime functions or they are retrieved from the NLS environment of the current session.

  • The character element RM is padded with trailing blanks to the length of 4, which is the length of 'viii'.

  • Other character elements and spelled-out numbers (SP, SPTH, and THSP suffixes) are not padded.

The FM modifier suppresses the above padding in the return value of the TO_CHAR function.

FX  Format exact. This modifier specifies exact matching for the character argument and datetime format model of a TO_DATE function:

  • Punctuation and quoted text in the character argument must exactly match (except for case) the corresponding parts of the format model.

  • The character argument cannot have extra blanks. Without FX, Oracle ignores extra blanks.

  • Numeric data in the character argument must have the same number of digits as the corresponding element in the format model. Without FX, numbers in the character argument can omit leading zeros.

    When FX is enabled, you can disable this check for leading zeros by using the FM modifier as well.

If any portion of the character argument violates any of these conditions, then Oracle returns an error message.

Format Model Examples

The following statement uses a date format model to return a character expression:

SELECT TO_CHAR(SYSDATE, 'fmDDTH')||' of '||TO_CHAR
   (SYSDATE, 'fmMonth')||', '||TO_CHAR(SYSDATE, 'YYYY') "Ides" 
    FROM DUAL; 

Ides 
------------------ 
3RD of April, 1998

The preceding statement also uses the FM modifier. If FM is omitted, then the month is blank-padded to nine characters:

SELECT TO_CHAR(SYSDATE, 'DDTH')||' of '||
   TO_CHAR(SYSDATE, 'Month')||', '||
   TO_CHAR(SYSDATE, 'YYYY') "Ides"
   FROM DUAL; 

Ides 
----------------------- 
03RD of April    , 1998 

The following statement places a single quotation mark in the return value by using a date format model that includes two consecutive single quotation marks:

SELECT TO_CHAR(SYSDATE, 'fmDay')||'''s Special' "Menu"
   FROM DUAL; 

Menu 
----------------- 
Tuesday's Special 

Two consecutive single quotation marks can be used for the same purpose within a character literal in a format model.

Table 2-17 shows whether the following statement meets the matching conditions for different values of char and 'fmt' using FX (the table named table has a column date_column of datatype DATE):

UPDATE table 
  SET date_column = TO_DATE(char, 'fmt');

Table 2-17 Matching Character Data and Format Models with the FX Format Model Modifier

char 'fmt' Match or Error?

'15/ JAN /1998'

'DD-MON-YYYY'

Match

' 15! JAN % /1998'

'DD-MON-YYYY'

Error

'15/JAN/1998'

'FXDD-MON-YYYY'

Error

'15-JAN-1998'

'FXDD-MON-YYYY'

Match

'1-JAN-1998'

'FXDD-MON-YYYY'

Error

'01-JAN-1998'

'FXDD-MON-YYYY'

Match

'1-JAN-1998'

'FXFMDD-MON-YYYY'

Match


Format of Return Values: Examples You can use a format model to specify the format for Oracle to use to return values from the database to you.

The following statement selects the salaries of the employees in Department 80 and uses the TO_CHAR function to convert these salaries into character values with the format specified by the number format model '$99,990.99':

SELECT last_name employee, TO_CHAR(salary, '$99,990.99')
   FROM employees
   WHERE department_id = 80;

Because of this format model, Oracle returns salaries with leading dollar signs, commas every three digits, and two decimal places.

The following statement selects the date on which each employee from Department 20 was hired and uses the TO_CHAR function to convert these dates to character strings with the format specified by the date format model 'fmMonth DD, YYYY':

SELECT last_name employee, 
    TO_CHAR(hire_date,'fmMonth DD, YYYY') hiredate
    FROM employees
    WHERE department_id = 20;

With this format model, Oracle returns the hire dates without blank padding (as specified by fm), two digits for the day, and the century included in the year.

See Also:

"Format Model Modifiers" for a description of the fm format element

Supplying the Correct Format Model: Examples When you insert or update a column value, the datatype of the value that you specify must correspond to the column datatype of the column. You can use format models to specify the format of a value that you are converting from one datatype to another datatype required for a column.

For example, a value that you insert into a DATE column must be a value of the DATE datatype or a character string in the default date format (Oracle implicitly converts character strings in the default date format to the DATE datatype). If the value is in another format, then you must use the TO_DATE function to convert the value to the DATE datatype. You must also use a format model to specify the format of the character string.

The following statement updates Hunold's hire date using the TO_DATE function with the format mask 'YYYY MM DD' to convert the character string '1998 05 20' to a DATE value:

UPDATE employees 
  SET hire_date = TO_DATE('1998 05 20','YYYY MM DD') 
  WHERE last_name = 'Hunold'; 

String-to-Date Conversion Rules

The following additional formatting rules apply when converting string values to date values (unless you have used the FX or FXFM modifiers in the format model to control exact format checking):

  • You can omit punctuation included in the format string from the date string if all the digits of the numerical format elements, including leading zeros, are specified. For example, specify 02 and not 2 for two-digit format elements such as MM, DD, and YY.

  • You can omit time fields found at the end of a format string from the date string.

  • If a match fails between a datetime format element and the corresponding characters in the date string, then Oracle attempts alternative format elements, as shown in Table 2-18.

Table 2-18 Oracle Format Matching

Original Format Element Additional Format Elements to Try in Place of the Original
'MM'

'MON' and 'MONTH'

'MON

'MONTH'

'MONTH'

'MON'

'YY'

'YYYY'

'RR'

'RRRR'


XML Format Model

The SYS_XMLGEN function returns an instance of type XMLType containing an XML document. Oracle provides the XMLFormat object, which lets you format the output of the SYS_XMLGEN function.

Table 2-19 lists and describes the attributes of the XMLFormat object. The function that implements this type follows the table.

See Also:

Table 2-19 Attributes of the XMLFormat Object

Attribute Datatype Purpose

enclTag

VARCHAR2(100)

The name of the enclosing tag for the result of the SYS_XMLGEN function. If the input to the function is a column name, then the default is the column name. Otherwise the default is ROW. When schemaType is set to USE_GIVEN_SCHEMA, this attribute also gives the name of the XMLSchema element.

schemaType

VARCHAR2(100)

The type of schema generation for the output document. Valid values are 'NO_SCHEMA' and 'USE_GIVEN_SCHEMA'. The default is 'NO_SCHEMA'.

schemaName

VARCHAR2(4000)

The name of the target schema Oracle uses if the value of the schemaType is 'USE_GIVEN_SCHEMA'. If you specify schemaName, then Oracle uses the enclosing tag as the element name.

targetNameSpace

VARCHAR2(4000)

The target namespace if the schema is specified (that is, schemaType is GEN_SCHEMA_*, or USE_GIVEN_SCHEMA)

dburl

VARCHAR2(2000)

The URL to the database to use if WITH_SCHEMA is specified. If this attribute is not specified, then Oracle declares the URL to the types as a relative URL reference.

processingIns

VARCHAR2(4000)

User-provided processing instructions, which are appended to the top of the function output before the element.


The function that implements the XMLFormat object follows:

STATIC FUNCTION createFormat(
     enclTag IN varchar2 := 'ROWSET',
     schemaType IN varchar2 := 'NO_SCHEMA',
     schemaName IN varchar2 := null,
     targetNameSpace IN varchar2 := null,
     dburlPrefix IN varchar2 := null, 
     processingIns IN varchar2 := null) RETURN XMLGenFormatType
       deterministic parallel_enable,
  MEMBER PROCEDURE genSchema (spec IN varchar2),
  MEMBER PROCEDURE setSchemaName(schemaName IN varchar2),
  MEMBER PROCEDURE setTargetNameSpace(targetNameSpace IN varchar2),
  MEMBER PROCEDURE setEnclosingElementName(enclTag IN varchar2), 
  MEMBER PROCEDURE setDbUrlPrefix(prefix IN varchar2),
  MEMBER PROCEDURE setProcessingIns(pi IN varchar2),
  CONSTRUCTOR FUNCTION XMLGenFormatType (
     enclTag IN varchar2 := 'ROWSET',
     schemaType IN varchar2 := 'NO_SCHEMA',
     schemaName IN varchar2 := null,
     targetNameSpace IN varchar2 := null,
     dbUrlPrefix IN varchar2 := null, 
     processingIns IN varchar2 := null) RETURN SELF AS RESULT
      deterministic parallel_enable,
  STATIC function createFormat2(
      enclTag in varchar2 := 'ROWSET',
      flags in raw) return sys.xmlgenformattype 
      deterministic parallel_enable
);