Character

A character is an element of a character string or keyword.

Syntax

<character> ::= <digit>
             | <letter>
             | <extended_letter>
             | <hex_digit>
             | <language_specific_character>
             | <special_character>

Digits

<digit> ::= 0 | 1 | 2 | | 3 | 4 | 5 | 6 | 7 | 8 | 9

Letters

<letter>    ::= A | B | C | D | E | F | G | H | I | J | K | L | M
              | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
              | a | b | c | d | e | f | g | h | i | j | k | l | m
              | n | o | p | q | r | s | t | u | v | w | x | y | z

Further Letters

<extended_letter> ::= # | @ | $

Hexadecimal Characters

<hex_digit> ::= 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
| A | B | C | D | E | F
| a | b | c | d | e | f

Language-Specific Characters

A language-specific character language_specific_character is any letter that occurs in a northern, southern, or central European language and is not contained in the list of letters.

German umlauts: д, ц, ь

French letters with a “grave” accent: а

If you have installed a UNICODE-enabled database instance, a language-specific character is a character that is not included in the ASCII code list from 0 to 127.

Special Characters

A special character is any character that is not contained in the following list:

?     Digits

?     Letters

?     Further letters

?     Hexadecimal characters

?     Language-specific characters

?     Characters that indicate the end of a line in a file

See also:

Character Set (token)

Literal (literal)