16.20.16.20 - 16.20 - CHARACTER Data Type - Teradata Vantage NewSQL Engine

Teradata Vantage™ Data Types and Literals

prodname
Teradata Database
Teradata Vantage NewSQL Engine
vrm_release
16.20
category
Programming Reference
featnum
B035-1143-162K

Purpose

Represents a fixed length character string for Teradata Database internal character storage.

Syntax





n
The number of characters or bytes allotted to the column defined with this server character set:
  • For the LATIN server character set, the maximum value for n is 64000 characters.
  • For the UNICODE and GRAPHIC server character sets, the maximum value for n is 32000 characters.
  • For the KANJISJIS server character set, the maximum value for n is 32000 bytes.
If a value for n is not specified, the default is 1.
server_character_set
The server character set for the character column being defined. See CHARACTER SET Phrase.
If the CHARACTER SET server_character_set clause is omitted, the default server character set depends on how the user is defined in the DEFAULT CHARACTER SET clause of the CREATE USER statement. See “CREATE USER” in Teradata Vantage™ SQL Data Definition Language Syntax and Examples, B035-1144.
In accordance with Teradata internationalization plans, KANJI1 support is deprecated and is to be discontinued in the near future. KANJI1 is not allowed as a default character set; the system changes the KANJI1 default character set to the UNICODE character set. Creation of new KANJI1 objects is highly restricted. Although many KANJI1 queries and applications may continue to operate, sites using KANJI1 should convert to another character set as soon as possible.
Supported values for server_character_set are as follows:
attributes
Appropriate data type, column storage, or column constraint attributes.
See Core Data Type Attributes and Storage and Constraint Attributes for specific information.

ANSI Compliance

CHARACTER is ANSI SQL:2011 compliant.

GRAPHIC is a Teradata extension to the ANSI SQL:2011 standard.

Storage

Character data is allocated either in terms of characters or in terms of bytes, depending on the server character set used. The number of bytes of storage per character also varies depending on the server character set, as illustrated by the following table.

Server Character Set Server Form-of-Use Server Space Allocation Sharable Among Heterogeneous Clients?
LATIN Fixed 8-bit LATIN Character-based Yes
UNICODE Fixed16-bit UNICODE
GRAPHIC Fixed 16-bit UNICODE
KANJISJIS Mixed single and multibyte KANJISJIS Byte-based Yes

External Representation of CHARACTER

Whenever a client application communicates with Teradata Database, it indicates its character set (form-of-use for character data). The server returns all character data to the client application in that form.

Any conversion to or from the client system data types is done by Teradata Database.

For information on the number of bytes exported for the CHARACTER type, see Teradata SQL Character Strings and Client Physical Bytes.

Display Format

The default display format of CHARACTER(n) is X(n). For example, X(5), where data ‘HELLO’ displays as ‘HELLO’.

GRAPHIC Data

You can use GRAPHIC to represent multibyte character data.

GRAPHIC(n) is equivalent to CHARACTER(n) CHARACTER SET GRAPHIC. For best practice, define all GRAPHIC(n) data as CHARACTER(n) CHARACTER SET GRAPHIC.

Each multibyte character in a graphic string is stored assuming two bytes per logical character. Therefore, a graphic data string always represents an even multiple of bytes.

If you specify GRAPHIC without the length (n), the default is GRAPHIC(1).

The following rules apply to truncation and padding of GRAPHIC data.

IF a graphic string is … THEN …
shorter than the specified length of the column the remaining space is filled with the graphic pad character.
longer than the specified length of the column the extra characters are truncated.

GRAPHIC Data and Client Character Sets

GRAPHIC types accommodate the following client character sets:
  • KanjiEBCDIC double byte graphic data
  • KanjiShift-JIS for double byte Shift-JIS codes
  • KanjiEUC for fixed-length, double byte EUC characters

Use the following syntax for KanjiEBCDIC graphic string literals:



Under a KanjiEBCDIC character set, multibyte characters in a graphic string constant must be delimited with the Shift-Out/Shift-In characters; for example:

INSERT INTO TableEBCDIC (ColGRAPH)
 VALUES (G'<AB>');

where AB is a valid string of KanjiEBCDIC multibyte characters, G specifies the string must be in the Graphic repertoire, and each apostrophe is a single byte character.

External Representation of GRAPHIC

The following table lists the client representation for the IBM DB2 GRAPHIC type.

Determining the application definitions and client data types is the responsibility of the application programmer.

Client CPU Architecture Client Internal Data Format
IBM mainframe 2n bytes of n DB2 GRAPHIC characters.

Related Topics

FOR information on … SEE …
character literals Character String Literals.
conversion of external-to-internal and internal-to-external character data, including truncation and error handling Teradata Vantage™ NewSQL Engine International Character Set Support, B035-1125.

Example: CHARACTER Data Type

In the following table definition, the column named Sex is assigned the CHARACTER data type with a length of one, and the column named Frgn_Lang is assigned the CHARACTER data type with a length of seven.

CREATE TABLE PersonalData
  (Id INTEGER
  ,Age INTEGER
  ,Sex CHARACTER NOT NULL UPPERCASE
  ,Frgn_Lang CHARACTER(7) NULL UPPERCASE );

Example: GRAPHIC Data and Client Character Sets

Consider the following table:

CREATE TABLE Product1Data
  (id1 INTEGER
  ,code1 CHARACTER(3) CHARACTER SET GRAPHIC);

Assume that column code1 contains the following data:

457F4577456D

Under a KanjiEBCDIC session in record or indicator mode, the contents of code1 are returned to the user as follows:

457F4577456D

Under a KanjiEBCDIC session in field mode, the contents of code1 are returned to the user in proper format, as follows:

0E457F4577456D0F