diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml index 941b101f393fdd0a127303dc05f016f2faf5467d..d759f3746b2a57dfd5f6f0ae9ad5dd6a3155362f 100644 --- a/doc/src/sgml/xfunc.sgml +++ b/doc/src/sgml/xfunc.sgml @@ -143,6 +143,21 @@ SELECT clean_emp(); </screen> </para> + <note> + <para> + 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., <command>CREATE TABLE</>), the effects + of such commands will not be visible during parse analysis of + later commands in the function. Thus, for example, + <literal>CREATE TABLE foo (...); INSERT INTO foo VALUES(...);</literal> + will not work as desired if packaged up into a single SQL function, + since <structname>foo</> won't exist yet when the <command>INSERT</> + command is parsed. It's recommended to use <application>PL/PgSQL</> + instead of a SQL function in this type of situation. + </para> + </note> + <para> The syntax of the <command>CREATE FUNCTION</command> command requires the function body to be written as a string constant. It is usually