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: ä, ö, ü
French letters with a “grave” accent: à
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: