Mohammad Heykal Abdillah wrote:
On Min, 2010-05-30 at 00:44 -0400, Andrew Dunstan wrote:
Mohammad Heykal Abdillah wrote:
Hi all,
Right now i am trying to understand how SQL parser is work.
My question is there anyway to get list of table name and its atribut
before raw parser is analyze?
Because i like to understand how PostgreSQL "break-down" the asterik at
target list, specialy in "natural join" case where PostgreSQL can give
query result that have unabigous attribut and match the right join key.
AIUI, expanding '*' is not done in the parser. The parser just makes an
A_star node.
See src/backend/gram.y for the parser spec.
Maybe you need to explain what exactly you're trying to do.
cheers
andrew
Yes that i know, expanding '*' is done in analyzer part. I am try to do
is, move the expanding process to "before" raw_parser that produce by
gram.y is processed by analyzer. Like this :
sql query -> gram.y -> raw_parse_tree -> (expand the '*') -> analyze
In this way analyzer part only receiving the expanded '*' parse tree
they wont expand the '*' again. I am aksing this because i didnt know
how to (analyzer) scan database so it can return list of attribut from
table. I have read the source code, and try manualy to replicate the
process (from what i got is the RTE function) with no result.
Ok, but why? What are you trying to achieve?
cheers
andrew
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