--- Beispiel für eine Stored Procedure in Tcl
CREATE FUNCTION isSystemUser(text) RETURNS boolean
AS '
set userId $1
set retval false
set fd [open /etc/passwd r]
while {[gets $fd line] >=0} {
set testId [lindex [split $line : ] 0]
if {[string equal $testId $userId]} {
set retval true
break
}
}
close $fd
return $retval'
LANGUAGE 'pltclu' ;
CREATE TABLE beispiel (
username name CHECK (isSystemUser(username))
);