diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml index 941b101f39..d759f3746b 100644 --- a/doc/src/sgml/xfunc.sgml +++ b/doc/src/sgml/xfunc.sgml @@ -143,6 +143,21 @@ SELECT clean_emp(); + + + The entire body of a SQL function is parsed before any of it is + executed. While a SQL function can contain commands that alter + the system catalogs (e.g., CREATE TABLE), the effects + of such commands will not be visible during parse analysis of + later commands in the function. Thus, for example, + CREATE TABLE foo (...); INSERT INTO foo VALUES(...); + will not work as desired if packaged up into a single SQL function, + since foo won't exist yet when the INSERT + command is parsed. It's recommended to use PL/PgSQL + instead of a SQL function in this type of situation. + + + The syntax of the CREATE FUNCTION command requires the function body to be written as a string constant. It is usually