Обсуждение: prepared statement incompatibility

Hello all,

We are using Postgres 8.0.3, and are attempting to upgrade to the JDBC 8.x drivers, but have discovered that PreparedStatements that used to work no longer do so.   This is seen where the Java type does not match the database type, such as attempting to use preparedStatement.setString(1, “1”)   where the database type is actually an integer (see stacktrace below).     These worked fine on previous driver versions (such as 7.4).     

If we set the protocolVersion=2,  the jdbc 8.x drivers will work fine also, but I’m not so sure we really want to do that.

At first, I thought this was related to the use of server side prepares.   But I have set the prepareThreshold=0 and verified it was being set by checking for it in the pgconnection and pgstatement, but it appears to have no effect.

Can anyone clarify what exactly has changed with prepared statements and why it used to work previously?   

Thanks,

Byron

Exception in thread "main" java.sql.SQLException: ERROR: column "ticket" is of type integer but expression is of type character varying

        at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:1471)

        at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1256)

        at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:175)

        at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:389)

        at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:330)

        at org.postgresql.jdbc2.AbstractJdbc2Statement.executeUpdate(AbstractJdbc2Statement.java:282)

        at test.routescape.orm.util.DriverTest.main(DriverTest.java:49)

But with the previous driver, we were actually using protocol version 3, so it doesn’t appear that the driver strictness is actually directly related to protocol version 3.    I’m curious as to what is it that actually changed in the 8.x drivers and why?      

Would it be possible to add a connection property to control just this strict type behavior, something like “strictTypes=false” ?   

BTW, we are not directly using JDBC, we are using Hibernate.   We have a lot of code that is not so strict with regard to datatypes in Hibernate queries and such, and that’s why it presents a difficult problem for us.

-----Original Message-----
From: Dave Cramer [mailto:pg@fastcrypt.com]
Sent: Tuesday, June 28, 2005 4:44 PM
To: Byron Nikolaidis
Cc: pgsql-jdbc@postgresql.org
Subject: Re: [JDBC] prepared statement incompatibility

The new driver is more strict about the use of setXXX. Your only option is to use protocol version 2 if you do not want to specify the correct underlying type.