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Re: getUdateCount() vs. RETURNING clause

From: Oliver Jowett <oliver(at)opencloud(dot)com>
To: Thomas Kellerer <spam_eater(at)gmx(dot)net>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: getUdateCount() vs. RETURNING clause
Date: 2009-11-25 11:13:40
Message-ID: 4B0D1164.1060006@opencloud.com (view raw or flat)
Thread:
Lists: pgsql-jdbc
Thomas Kellerer wrote:

> Hmm, my understand was a bit different.
> The Javadocs simply say
> 
> There are no more results when the following is true:
> ((stmt.getMoreResults() == false) && (stmt.getUpdateCount() == -1))
> 
> It doesn't state that they are mutually exclusive. And for me it seemed 
> to imply that I can call getMoreResults() and getUpdateCount() in a loop 
> in order to process everything that is returned.
> 
> Additionally the Javadocs for getUpdateCount() says:
> 
> "Gets the *current* result as an update count" and ".. if there are no 
> more results it returns -1"


You've done some selective editing there. The javadoc I referred to is 
this (from the Java 6 javadoc):

getResultSet():

Retrieves the current result as a ResultSet object. This method should 
be called only once per result.

Returns: the current result as a ResultSet object or null if the result 
is an update count or there are no more results

---

getUpdateCount():

Retrieves the current result as an update count; if the result is a 
ResultSet object or there are no more results, -1 is returned. This 
method should be called only once per result.

Returns: the current result as an update count; -1 if the current result 
is a ResultSet object or there are no more results

---

I think that's fairly clear: the "current result" is either a ResultSet, 
or an update count, but it can't be both. getUpdateCount() explicitly 
says that it returns "-1 [...] if the current result is a ResultSet 
object", and getResultSet() explicitly says that it returns "null if the 
[current] result is an update count."

> The word "current" here also let me to believe I can call those methods 
> multiple times.

 From memory the postgresql driver doesn't care if you call them 
multiple times, but FWIW the javadoc says that you should only call them 
once per result.

-O

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Subject: Re: getUdateCount() vs. RETURNING clause
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