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Date: Fri, 18 Dec 2009 23:57:53 +0800
From: "suzhiyang" <suzhiyang@gmail.com>
To: "pgsql-hackers" <pgsql-hackers@postgresql.org>
Subject: Distinguish view and table problem
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Hi!
I just want to distinguish a view and a table while postgres execute exec_simple_query(). In the systable of pg_class, a view and a table has different relkind ('r' 'v'). But when I print the parsetree and the rewrite parsetree, I found that a view and a table has no character to distinguish because the structure Relation has no attribute called relkind. Maybe I should read systable to confirm that we are select from a view or table? But there's still has problem. How could I get the relkind of a table(view) by its name from pg_class?
Another question is that does postgres save the user's original query_string at anywhere(systable etc.)? If I want to save the sourceText in the systable, I could add a column to pg_class called query_string. How could I insert a line to pg_class or read a line from it?

Thank you very much!

2009-12-18 



suzhiyang
 

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<META content="MSHTML 6.00.2900.3603" name=GENERATOR><LINK 
href="BLOCKQUOTE{margin-Top: 0px; margin-Bottom: 0px; margin-Left: 2em}" 
rel=stylesheet></HEAD>
<BODY style="FONT-SIZE: 10pt; MARGIN: 10px; FONT-FAMILY: verdana">
<DIV style="TEXT-INDENT: 2em"><FONT face=Verdana size=2>Hi!</FONT></DIV>
<DIV style="TEXT-INDENT: 2em">I just want to distinguish a view and a table 
while postgres execute exec_simple_query(). In the systable of pg_class, a view 
and a table has different relkind ('r' 'v'). But when I print the parsetree and 
the rewrite parsetree, I found that a view and a table has no character to 
distinguish because the structure Relation has no attribute called relkind. 
Maybe I should read systable to confirm that we are select from a view or table? 
But there's still has problem. How could I get the relkind of a table(view) by 
its name from pg_class?</DIV>
<DIV style="TEXT-INDENT: 2em">Another question is that does postgres save the 
user's original query_string at anywhere(systable etc.)? If I want to save the 
sourceText in the systable, I could add a column to pg_class called 
query_string. How could I insert a line to pg_class or read a line from 
it?</DIV>
<DIV style="TEXT-INDENT: 2em">&nbsp;</DIV>
<DIV style="TEXT-INDENT: 2em">Thank you very much!</DIV>
<DIV><FONT face=Verdana size=2></FONT>&nbsp;</DIV>
<DIV align=left><FONT face=Verdana color=#c0c0c0 size=2>2009-12-18 
</FONT></DIV><FONT face=Verdana size=2>
<HR style="WIDTH: 122px; HEIGHT: 2px" align=left SIZE=2>

<DIV><FONT face=Verdana color=#c0c0c0 size=2><SPAN>
<DIV>suzhiyang</DIV></SPAN> </FONT></DIV></FONT></BODY></HTML>

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