Simple identifier 

Simple identifier. The first character in a simple identifier must not be a digit or underscore.

Syntax

<simple identifier> ::= <first character>[<identifier tail character>...]

First character, identifier tail character

Explanation

Simple identifiers are always converted into uppercase characters in the database. For this reason, simple identifiers are not case sensitive.

If the name of a database object is to contain lowercase letters, special characters, or blanks, the identifier must be specified as a special identifier (in double quotes).