A character set (token) comprises a series of characters that are combined to form a lexical unit. A distinction is made between regular and delimiter tokens.
<token> ::= <regular token> | <delimiter token>
<regular_token> ::= <literal> | <key_word> | <identifier> | <parameter_name>
<delimiter_token> ::= ( | ) | , | . | + | - |
* | / | < | > | <> | != | = | <= | >=
| ~= | ~< | ~> (for
computers with ASCII code)
SELECT * FROM reservation
ALTER TABLE reservation DROP FOREIGN KEY customer_reservation
'Reisen10'
Each token can be followed by any number of blanks. Each regular token regular_token must be followed by a delimiter_token or a blank.
Double quotation marks within a special identifier are represented by two consecutive quotation marks.