In which module does query rewriting takes place

Hi,<br /><br />We are trying to introduce access control. For this we have to rewrite the input query by replacing each
relationby its corresponding authorized view. Which part of the code should we modify for this. <br /><br />Till now we
havethought of the following: <br /><br />1. We take as input the parse tree generated by the parser.<br />2. We
implementa "new" module which rewrites the parse tree into the format we want.<br />3. We feed this new parse tree into
theoptimizer.<br /><br />Does a module exist which rewrites the parse tree generated. We saw that there exist some
rewritemodule in /src/backend/rewrite. Is that the correct module to make changes to!<br /><br />Thanks<br />Shaunak<br
clear="all"/><br />-- <br />It is not the aptitude but the attitude that decides a persons altitude<br />Shaunak
Godbole<br/>Senior Undergraduate<br />Computer Science Dept.<br />IIT Powai, Mumbai 400076<br />Ph no: 9819841537