Delimited Identifiers 

A delimited identifier is an arbitrary sequence of characters (the delimited identifier body), which is enclosed by double quotes.

Syntax

<delimited identifier> ::= <double quote> <delimited identifier body> <double quote>. <delimited identifier body> is a sequence of any character other than the <double quote>

 

A <regular identifier> is equivalent to a <delimited identifier> if the <delimited identifier body> of the <delimited identifier> is the <regular identifier> with every lower case letter replaced with its equivalent upper case letter.

The following table gives an overview which identifiers are equivalent.

Equivalence of Regular and Delimited Identifiers.

	Hugo	hugo	HUGO	“Hugo”	“hugo”	“HUGO”
Hugo	equivalent	equivalent	equivalent	different	different	equivalent
hugo	equivalent	equivalent	equivalent	different	different	equivalent
HUGO	equivalent	equivalent	equivalent	different	different	equivalent
“Hugo”	different	different	different	equivalent	different	different
“hugo”	different	different	different	different	equivalent	different
“HUGO”	equivalent	equivalent	equivalent	different	different	equivalent

 

Regular Identifiers are interpreted in upper case. Delimited Identifiers are case sensitive.

Example

SELECT "col" FROM "dbtab" WHERE "DBTAB"."COL" = 'abc'

Delimited Identifiers. In this example, "col" and "COL" denominate different columns, "dbtab" and "DBTAB" denominate different tables.

SELECT col FROM dbtab WHERE "dbtab"."COL" = 'abc'

Regular and Delimited Identifiers. Here, col and "COL" denominate one and the same column, dbtaband “dbtab” denominate different tables.

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Keywords