2.3. Identifiers

All database objects have names, often called identifiers. Two types of names are valid as identifiers: regular names, similar to variable names in regular programming languages, and delimited names that are specific to SQL. To be valid, each type of identifier must conform to a set of rules, as follows:

2.3.1. Rules for Regular Object Identifiers

• Length cannot exceed 31 characters

• The name must start with an unaccented, 7-bit ASCII alphabetic character. It may be followed by other 7-bit ASCII letters, digits, underscores or dollar signs. No other characters, including spaces, are valid. The name is case-insensitive, meaning it can be declared and used in either upper or lower case. Thus, from the system’s point of view, the following names are the same:

  fullname
  FULLNAME
  FuLlNaMe
  FullName

Regular name syntax

<name> ::=
  <letter> | <name><letter> | <name><digit> | <name>_ | <name>$
<letter> ::= <upper letter> | <lower letter>
<upper 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
<lower 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
<digit> ::= 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9

2.3.2. Rules for Delimited Object Identifiers

• Length cannot exceed 31 characters

• The entire string must be enclosed in double-quotes, e.g. "anIdentifier"

• It may contain characters from any Latin character set, including accented characters, spaces and special characters

• An identifier can be a reserved word

• Delimited identifiers are case-sensitive in all contexts

• Trailing spaces in delimited names are removed, as with any string constant

• Delimited identifiers are available in Dialect 3 only. For more details on dialects, see SQL Dialects

Delimited name syntax

<delimited name> ::= "<permitted_character>[<permitted_character> …]"