Description

pg_quote returns its argument in single quotes, with added characters which makes it safe for use as an SQL string constant. It returns the string in single quotes, with all internal single quote marks doubled, and in some cases doubles backslash characters too.

For example, pg_quote {can't} returns the string 'can''t'.

Arguments

Return Value

The string argument, in single quotes, with added characters.

Notes

See also pg_escape_string, which returns the same thing but without the surrounding single quotes, pg_escape_literal, which is an alternative implementation of pg_quote, and pg_escape_identifier.

This command was added in pgtclng-1.5.1 and in pgintcl-2.1.0.

The optional conn argument was added to this command in pgtclng-1.7.0 and in pgintcl-3.1.0.

The conn argument is used to get character set encoding information, and the state of the PostgreSQL server configuration parameter standard_conforming_strings. The character set encoding is used to make sure that multi-byte characters do not confuse the escaping process. The state of the standard conforming strings setting is used to determine if backslashes need to be doubled. If the conn parameter is supplied, these settings can be accurately determined for the specific database connection being used. (Note that this information is maintained on the client side and does not necessitate any additional database server traffic.)

If the conn parameter is not supplied, a best guess will be made based on the most recent information from any database connection by the client. Therefore, if the client makes a single database connection, or multiple connections with the same encoding and setting for standard_conforming_strings, there is no need to provide the conn parameter.

This command uses or emulates the PostgreSQL libpq function PQescapeString, if no connection handle is supplied, or PQescapeStringConn if a connection handle is supplied. Surrounding single quotes are added to the result.

Example

set sql "SELECT * FROM mytable WHERE name = [pg_quote $itemname]"