Re: Why?? executeQuery() & exception: "No results were returned by the query."

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Panu Outinen <panu(at)vertex(dot)fi>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: Why?? executeQuery() & exception: "No results were returned by the query."
Date: 2001-05-08 19:32:19
Message-ID: 200105081932.f48JWJ824950@candle.pha.pa.us
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Are you saying that this "no result" error is required by the JDBC
standard, or is it a PostgreSQL bug?

> Hi there !
>
> Can anyone explain why does executeQuery() throws an exception
> "No results were returned by the query."
> when result set is empty ???????
>
> In my opinion (and also e.g. Oracle's JDBC driver's opinion) that this is
> just normal and user can check the number of rows (=0) that none was
> returned. It's totally different to make a query where something is wrong
> in the query itself e.g. non-existant column is used or perhaps in the
> database connection!
>
> This is "pain in the *ss" to test against in one's code for every different
> JDBC driver's DIFFERENT return string there available and it's impossible
> to do code that works for even unknown drivers. And Postgresql has even
> language dependant versions of this !!!
>
> Since Postgresql source code is so nicely publicly available (thank you all
> there!) and thus improvements are easily given by anyone I just wonder if
> this could be improved, please !!!
>
> - Panu
>
> PS. I know for sure that at least SQL Server throws the following when used
> through JDBC-ODBC bridge: "No ResultSet was produced".
>
>
> ----------------------------------------------------------------------
>
> org\postgresql\jdbc2\Statement.java:
>
> ...
> /**
> * Execute a SQL statement that retruns a single ResultSet
> *
> * @param sql typically a static SQL SELECT statement
> * @return a ResulSet that contains the data produced by the query
> * @exception SQLException if a database access error occurs
> */
> public java.sql.ResultSet executeQuery(String sql) throws SQLException
> {
> this.execute(sql);
> while (result != null &&
> !((org.postgresql.ResultSet)result).reallyResultSet())
> result = ((org.postgresql.ResultSet)result).getNext();
> if (result == null)
> throw new PSQLException("postgresql.stat.noresult");
> return result;
> }
> ...
>
> ----------------------------------------------------------------------
>
>
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--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
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