Chapter 6 SQL Language Elements
223
Identifiers
Identifiers represent names of objects in the database, such as user IDs,
tables, and columns.
Identifiers consist of any string of alphabetic characters or digits. The first
character of an identifier must be an alphabetic character, not a digit.
Alternatively, any string of characters can be used as an identifier by
enclosing it in quotation marks ("double quotes") as long as the
QUOTED_IDENTIFIER database option is set to ON.
The underscore character (_), at sign (@), number sign (#), and dollar sign
($) are considered alphabetic characters. The database collation sequence
dictates which characters are considered alphabetic or digit characters.
A quotation mark inside the identifier is represented by two quotation marks
in a row.
Identifiers have a maximum length of 128 bytes.
Reserved words play an important role in the syntax of the SQL language. If
you choose to use a reserved word as an identifier, you must enclose it in
double quotes even if it does not have spaces.
The following are all valid identifiers.
Surname
"Surname"
SomeBigName
"Client Number"
"With a quotation "" mark"
$ For a complete list of the reserved words, see "Reserved words" on
page 220.
$ For information on the QUOTED_IDENTIFIER option, see
"QUOTED_IDENTIFIER option" on page 207.
Function
Description
Examples
See also
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