The DELIMIDENT Environment Variable

If the DELIMIDENT environment variable is set on the database server, you cannot use double quotes ( " ) to delimit literal strings. If DELIMIDENT is set, the database server interprets strings enclosed in double quotes as SQL identifiers, not as literal strings. If DELIMIDENT is not set, a string between double quotes is interpreted as a literal string, not an identifier. For further information, see Using Quotes in Strings, and the description of DELIMIDENT in IBM Informix Guide to SQL: Reference.

3DELIMIDENT is also supported on client systems, where it can be set to y, to n, or to no setting.

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• y specifies that client applications must use single quote 3( ' ) symbols to delimit literal strings, and must use 3double quote ( " ) symbols only around delimited SQL 3identifiers. Delimited identifiers can support a larger character set than 3is valid for undelimited identifiers. Letters within delimited strings or 3delimited identifiers are case-sensitive.
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• n specifies that client applications can use double quote ( " ) or single quote ( ' ) symbols 3to delimit character strings, but not to delimit SQL identifiers. If the 3database server encounters a string delimited by double or single quote symbols 3in a context where an SQL identifier is required, it issues an error. An owner 3name, however, that qualifies an SQL identifier can be delimited by single 3quote ( ' ) symbols. You must use a pair of the same 3quote symbols to delimit a character string.
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• Specifying DELIMIDENT with no value on the client 3system requires client applications to use the DELIMIDENT setting that is the default for their application programming interface 3(API).

Client APIs of Dynamic Server use the following default 3DELIMIDENTsettings:

• 3For OLE DB and .NET, the default DELIMIDENT setting is y
• 3For ESQL/C, JDBC, and 3ODBC, the default DELIMIDENT setting is n
• 3APIs that have 3ESQL/C as an underlying layer, such as Informix 4GL, the DataBlade API (LIBDMI), 3and the C++ API, behave as ESQL/C, and use 'n' as the default if no value 3for DELIMIDENT is specified on the client system.

3Even if DELIMIDENT is set, you can 3use single quote ( ' ) symbols to delimit authorization identifiers as the owner name component of a database object 3name, as in the following example:

RENAME COLUMN 'Owner'.table2.collum3 TO column3

The general rule, however, is that when DELIMIDENT is set, the SQL parser interprets strings delimited by single quotes 3as string literals, and interprets character strings delimited by double quotes 3( " ) as SQL identifiers.