inserting boolean values in dynamic queries

Hi,

I'm building a dynamic query as described at
http://www.postgresql.org/docs/8.3/interactive/plpgsql-statements.html#PLPGSQL-STATEMENTS-EXECUTING-DYN
:

EXECUTE 'UPDATE tbl SET '       || quote_ident(colname)       || ' = '       || quote_literal(newvalue)       || '
WHEREkey = '       || quote_literal(keyvalue); 



It works fine, except when I want to include a boolean value: the cast
of newvalue from boolean to text causes problem.

I can change my code and work with 't' and 'f' values as text, but
wondered if there wasa way to use boolean values in a dynamically
generated query.

Thanks

Raphaël

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