Identifiers are the names of objects in the database, such as user IDs, tables, and columns.
Identifiers have a maximum length of 128 bytes and are composed from alphabetic characters and digits, as well as the underscore character (_) and at sign (@). Leading digits are allowed but the identifier must be quoted. Other special characters are allowed but the identifier must be quoted. The database collation sequence dictates which characters are considered alphabetic or digit characters.
Double quotes (") are not permitted in identifiers:
If any of the following conditions are true, then always enclose an identifier in double quotes:
The identifier contains leading, trailing, or embedded spaces.
The first character of the identifier is not an alphabetic character, the underscore character (_), or at sign (@). For example, the first character is a digit.
The identifier contains characters other than the alphabetic characters, digits, underscore character (_), and at sign (@).
The identifier is a reserved word.
For compatibility with other database management systems, it is recommended that you avoid the use of special characters in identifier names, including but not limited to any of the following:
Leading or trailing whitespace
Leading single quote
Semicolons