Identifier

Identifier A distinction is made between simple identifiers (simple_identifier) and special identifiers (special_identifier).

Syntax

<identifier> ::= <simple_identifier>
| <double_quotes><special_identifier><double_quotes>

Simple Identifier

<simple_identifier> ::= <first_character>[<identifier_tail_character>...]

<first_character>           ::= <letter>
                              | <extended_letter>
                              | <language_specific_character>

<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

<extended_letter>           ::= # | @ | $

<identifier_tail_character> ::= <digit>
                              | <letter>
                              | <extended_letter>
                              | <language_specific_character>
                              | <underscore>

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

<underscore> ::= _

Special Identifier

<special_identifier> ::= <special_identifier_character>...

<special_identifier_character> ::= any characters, that can be linked in any sequence !>

<double_quotes>                ::= "

Simple identifier: reservation

Special identifier: "ADD", "Example_1"

Explanation

Identifiers can be entered in uppercase/lowercase characters.

Simple Identifier

When you specify simple identifiers (simple_identifier), upper and lower-case are ignored, as the system always converts the identifier to upper-case letters.

The first character in a simple identifier must not be a digit or underscore (underscore). Reserved keywords must not be used in simple identifiers.

Special Identifier

Special identifiers (special_identifier) are always used as specified in the database, that is, upper and lower-case characters are taken into account. Special identifiers are case sensitive.

If the name of a database object is to contain lower-case letters, special characters, reserved keywords, or blanks, the identifier must be specified as a special identifier that is enclosed in double quotation marks (double_quotes).

Double quotation marks within a special identifier are represented by two consecutive quotation marks.

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.

See also:

Literal (literal)

Character Set (token)