A distinction is made between simple identifiers and special identifiers.
Syntax
<identifier> ::= <simple_identifier> | <double_quotes><special_identifier><double_quotes>
simple_identifier, double_quotes, special_identifierExplanation
Identifiers can be entered in uppercase/lowercase characters.
Reserved keywords must not be used in simple identifiers. Reserved keywords, however, can be specified in the form of special identifiers.Double quotes within a special identifier are represented by two consecutive quotes.
Simple identifier:
Special identifier:
"ADD"