RE: [hibernate-dev] Connection proxying
by Steve Ebersole
Depends... Do you mean the current session.connection()? If so, then
no, they will not be the same. Currently, session.connection() enforces
that the connection is usable until (1) the connection is "closed" or
(2) the transaction ends. If you tried the Work code you listed, that
guarantee would not hold; the connection is only guaranteed to be valid
during the performWork() call.
No one is saying (at least I don't think so) that either of those cases
is unimportant (I actually do not understand how your ConnectionProvider
reference fits there though). On the contrary, I specifically said we
would need a plan for handling the sf.openSession( s.connection() ) case
in my original e-mail. The question was simply whether exposing the
Work/command APIs justify removal of the connection() method from the
perspective of using it for direct JDBC work. I do not know that answer
to that. Unfortunately, I suspect it does not and that we will need to
keep connection() around; but one can dream.
-----Original Message-----
From: Max Andersen
Sent: Wednesday, August 30, 2006 12:08 PM
To: Steve Ebersole
Cc: hibernate-dev(a)lists.jboss.org
Subject: Re: [hibernate-dev] Connection proxying
> Session s = ...;
> Connection c = s.connection();
> PS stmnt = c.prepareStatement( ... );
> RS rs = stmnt.executeQuery();
> s.load( ... );
> rs.next();
> ...
>
> Seems harmless enough, right? Will it work? Answer: well it depends
;)
> Both the ConnectionProvider being used and the connection release mode
> configured play parts in this (which is a PIA to explain and even more
> so to justify). This is exactly the scenario which forced me to add
the
> notion of BorrowedConnectionProxy to the core as it is now in the
first
> place, so that the behavior could be consistent; the downside is that
it
> essentially overrides *any* connection releasing.
ah yes - it comes down to the release mode. Now I remember.
so should we start by @deprecate connection() in 3.2 ?
We don't really have any other portable way of exposing the connection
running the same tx as the session.
> If you as a user are doing some work with the connection obtained from
a
> Hibernate Session, how big of a disruption is it to change from that
> usage pattern to this new usage pattern. And whether than disruption
is
> then adequately offset by any advantages of this new usage pattern.
Yes, and for the usecase of simply getting a connection and do a
"one-off"
task
the change is not a big deal.
The issue comes when you are in the scenario of having mixed Hibernate
and
JDBC code;
here getting access to a shared connection is good (session.connection()
is one, openSession(connection) is another and ConnectionProvider is a
third)
But I would argue all three are relevant, but I would also be completely
fine
by giving those who want to have "unbounded" access a bigger burden
..e.g.
remembering to close the connection,
live with releasemode being circumvented etc.
> The advantages are the typical "avoid tedious error handling", "avoid
> redundant resource management", blah-blah-blah you heard from every
> other library supporting delegation/templating solutions to JDBC
access.
> Additionally, you get integration with our notion of connection
release
> modes, exception conversion, logging, etc. Some of those "extras"
could
> be achieved even via exposing the proxy rather than the "raw"
> connection, but the connection release modes are explicitly
> circumvented...
I don't talk against having the new thing exposed, fine by me.
I just think there still is a important "niche" usage for
session.connection(). (not forgetting many books, training, examples,
applications that refers to this method)
On that note:
Will the following snippet be equal to c = session.connection() ?
final Connection[] c = new Connection[1];
session.doWork(
new Work() {
public void performWork(Workspace workspace) {
c[0] = workspace.getConnection();
}
}
);
/max
>
> -----Original Message-----
> From: Max Andersen
> Sent: Wednesday, August 30, 2006 9:09 AM
> To: Steve Ebersole
> Cc: hibernate-dev(a)lists.jboss.org
> Subject: Re: [hibernate-dev] Connection proxying
>
>
>> However, removing that connection() method does additionally create
an
>> issue in regards to how to then deal with the common usage pattern of
>> "subordinate sessions": sf.openSession( s.connection() )... One
> thought
>> was to add either a sf.openSubordinateSession( s ) or even
>> s.openSubordinateSession()
>
> and...
> openSubordinateSession(Interceptor)
> openSubordinateStatelessSession()
>
> its a loong name...and isn't the session one gets from getSession a
more
>
> true
> "subordinate" ?
>
> Needs a better name....or maybe just keep session.connection() around
?
> :)
>
> What are the arguments *against* session.connection() if you do the
> proxying you
> are suggesting ?
>
> /max
>
>> -----Original Message-----
>> From: Max Andersen
>> Sent: Wednesday, August 30, 2006 2:30 AM
>> To: Steve Ebersole; hibernate-dev(a)lists.jboss.org
>> Subject: Re: [hibernate-dev] Connection proxying
>>
>> Since the intention is to provide a safer execution for the user then
>> +1,
>> but if you are going to do this then i guess session.connection()
will
>> still be ok
>> since it will just be proxied.
>>
>> btw. your example is a bit simplified since when hibernate runs
inside
>> an
>> appserver
>> the user will normally also have to cast through the appservers
>> "proxying".
>>
>> ( ( OracleConnection ) (( AppServerConnection ) (
HibernateConnection
> )
>>
>> connection ).getWrappedConnection()
>> ).getNativeConnection()).doSomethingOracleSpecific()
>>
>> ...but I guess we will then soon see NativeJdbcExtractorAdapter
>> implementation for Hibernate ;)
>>
>> /max
>>
>>
>>
>>> This is in regards to the JDBC interaction code I recently committed
>>> into the sandbox in SVN.
>>>
>>> I am considering proxying the JDBC connections specifically for the
>>> purpose of auto-registering "subordinate objects" (result sets and
>>> statements) for automatic cleanup. Currently the registration is a
>>> manual process in order to take advantage of the automatic cleanup
>> (have
>>> a look at org.hibernate.jdbc4.jdbc.impl.BasicWorkTest for the basic
>>> usage pattern). Specifically what I am thinking is taking a page
> from
>>> how app servers implement Connection handles in relation to data
>>> sources:
>>>
>>> public interface HibernateConnection extends java.sql.Connection {
>>> public Connection getWrappedConnection();
>>> }
>>>
>>> Of course this makes it more difficult for anyone depending on
> casting
>>> to a particular driver's Connection impl at some point. But,
>>> considering that this is atypical usage, my thought was to treat it
> as
>>> the more complex use-case; and since this generally requires casting
>>> anyway, one extra cast and "extraction" is not that big of a deal to
>> me.
>>> For example, to get an oracle connection (for LOB handling for
>> example):
>>> ( ( OracleConnection ) connection ).doSomethingOracleSpecific() -> (
> (
>>> OracleConnection ) ( ( HibernateConnection ) connection
>>> ).getWrappedConnection() ).doSomethingOracleSpecific()
>>>
>>> Plus, would potentially allow for some other niceties like automatic
>>> statement logging (perhaps even with parameter replacement).
>>>
>>> Thoughts?
>>>
>>> _______________________________________________
>>> hibernate-dev mailing list
>>> hibernate-dev(a)lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>>
>>
>>
>
>
>
--
--
Max Rydahl Andersen
callto://max.rydahl.andersen
Hibernate
max(a)hibernate.org
http://hibernate.org
JBoss a division of Red Hat
max.andersen(a)jboss.com
17 years, 8 months
Insert not working
by Dinesh Chaturvedi
Hi,
I have just started working on hibernate. I was trying to start with some
sample applications.
I am facing this problem when I am trying to insert data. It does not throw
any error but does not do any insert.
I can easily fetch information using the same mapping.
Can someone help me with this.
I am using MYSQL5 with hibernate 3
My hibernate-cfg.xml loooks like following
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">
com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url
">jdbc:mysql://localhost/test</property>
<property name="hibernate.connection.username">root</property>
<property name="hibernate.connection.password"></property>
<property name="hibernate.connection.pool_size">10</property>
<property name="show_sql">true</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Mapping files -->
<mapping resource="contact.hbm.xml"/>
</session-factory>
</hibernate-configuration>
my contact.hbm.xml looks like
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="com.test.dbo.contact" table="contacts">
<id name="id" type="long" column="id" >
<generator class="increment"/>
</id>
<property name="email">
<column name="email" />
</property>
<property name="modified_date">
<column name="modified_date"/>
</property>
</class>
</hibernate-mapping>
The Java Code looks like the following
SessionFactory factory = null;
try
{
Configuration cfg = new Configuration();
factory = cfg.configure().buildSessionFactory();
Session session = factory.openSession();
notification_email ne = createNotificationEmail();
session.save(ne);
session.flush();
session.close();
}
catch(Exception e)
{
System.out.println(""+e);
e.printStackTrace();
}
I will greatly appreciate if someone can provide me an answer. Really
struggling. thanks
--
Dinesh Chaturvedi
17 years, 8 months
RE: [hibernate-dev] Connection proxying
by Steve Ebersole
Imagine this usage:
Session s = ...;
Connection c = s.connection();
PS stmnt = c.prepareStatement( ... );
RS rs = stmnt.executeQuery();
s.load( ... );
rs.next();
...
Seems harmless enough, right? Will it work? Answer: well it depends ;)
Both the ConnectionProvider being used and the connection release mode
configured play parts in this (which is a PIA to explain and even more
so to justify). This is exactly the scenario which forced me to add the
notion of BorrowedConnectionProxy to the core as it is now in the first
place, so that the behavior could be consistent; the downside is that it
essentially overrides *any* connection releasing.
But, regardless, I do not like exposing the connection for "unbounded"
use. It leads to too many quirks and difficulties like the one
mentioned above. I think it really comes down to the answer to this
question:
If you as a user are doing some work with the connection obtained from a
Hibernate Session, how big of a disruption is it to change from that
usage pattern to this new usage pattern. And whether than disruption is
then adequately offset by any advantages of this new usage pattern.
And to be clear, what I am talking about is along the lines of...
Old:
Connection c = session.connection();
try {
// do work with the connection
}
catch( SQLException sqle ) {
...
}
finally {
c.close();
}
New:
session.doWork(
new Work() {
public void performWork(Workspace workspace) {
Connection c = workspace.getConnection();
// do work with the connection
}
}
);
The advantages are the typical "avoid tedious error handling", "avoid
redundant resource management", blah-blah-blah you heard from every
other library supporting delegation/templating solutions to JDBC access.
Additionally, you get integration with our notion of connection release
modes, exception conversion, logging, etc. Some of those "extras" could
be achieved even via exposing the proxy rather than the "raw"
connection, but the connection release modes are explicitly
circumvented...
-----Original Message-----
From: Max Andersen
Sent: Wednesday, August 30, 2006 9:09 AM
To: Steve Ebersole
Cc: hibernate-dev(a)lists.jboss.org
Subject: Re: [hibernate-dev] Connection proxying
> However, removing that connection() method does additionally create an
> issue in regards to how to then deal with the common usage pattern of
> "subordinate sessions": sf.openSession( s.connection() )... One
thought
> was to add either a sf.openSubordinateSession( s ) or even
> s.openSubordinateSession()
and...
openSubordinateSession(Interceptor)
openSubordinateStatelessSession()
its a loong name...and isn't the session one gets from getSession a more
true
"subordinate" ?
Needs a better name....or maybe just keep session.connection() around ?
:)
What are the arguments *against* session.connection() if you do the
proxying you
are suggesting ?
/max
> -----Original Message-----
> From: Max Andersen
> Sent: Wednesday, August 30, 2006 2:30 AM
> To: Steve Ebersole; hibernate-dev(a)lists.jboss.org
> Subject: Re: [hibernate-dev] Connection proxying
>
> Since the intention is to provide a safer execution for the user then
> +1,
> but if you are going to do this then i guess session.connection() will
> still be ok
> since it will just be proxied.
>
> btw. your example is a bit simplified since when hibernate runs inside
> an
> appserver
> the user will normally also have to cast through the appservers
> "proxying".
>
> ( ( OracleConnection ) (( AppServerConnection ) ( HibernateConnection
)
>
> connection ).getWrappedConnection()
> ).getNativeConnection()).doSomethingOracleSpecific()
>
> ...but I guess we will then soon see NativeJdbcExtractorAdapter
> implementation for Hibernate ;)
>
> /max
>
>
>
>> This is in regards to the JDBC interaction code I recently committed
>> into the sandbox in SVN.
>>
>> I am considering proxying the JDBC connections specifically for the
>> purpose of auto-registering "subordinate objects" (result sets and
>> statements) for automatic cleanup. Currently the registration is a
>> manual process in order to take advantage of the automatic cleanup
> (have
>> a look at org.hibernate.jdbc4.jdbc.impl.BasicWorkTest for the basic
>> usage pattern). Specifically what I am thinking is taking a page
from
>> how app servers implement Connection handles in relation to data
>> sources:
>>
>> public interface HibernateConnection extends java.sql.Connection {
>> public Connection getWrappedConnection();
>> }
>>
>> Of course this makes it more difficult for anyone depending on
casting
>> to a particular driver's Connection impl at some point. But,
>> considering that this is atypical usage, my thought was to treat it
as
>> the more complex use-case; and since this generally requires casting
>> anyway, one extra cast and "extraction" is not that big of a deal to
> me.
>> For example, to get an oracle connection (for LOB handling for
> example):
>> ( ( OracleConnection ) connection ).doSomethingOracleSpecific() -> (
(
>> OracleConnection ) ( ( HibernateConnection ) connection
>> ).getWrappedConnection() ).doSomethingOracleSpecific()
>>
>> Plus, would potentially allow for some other niceties like automatic
>> statement logging (perhaps even with parameter replacement).
>>
>> Thoughts?
>>
>> _______________________________________________
>> hibernate-dev mailing list
>> hibernate-dev(a)lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>
>
>
--
--
Max Rydahl Andersen
callto://max.rydahl.andersen
Hibernate
max(a)hibernate.org
http://hibernate.org
JBoss a division of Red Hat
max.andersen(a)jboss.com
17 years, 8 months
RE: [hibernate-dev] Connection proxying
by Steve Ebersole
Not sure. You know I would love to get rid of Session.connection()
completely. Guess it depends on how clean and generally useful this new
Work and command code becomes.
However, removing that connection() method does additionally create an
issue in regards to how to then deal with the common usage pattern of
"subordinate sessions": sf.openSession( s.connection() )... One thought
was to add either a sf.openSubordinateSession( s ) or even
s.openSubordinateSession()
-----Original Message-----
From: Max Andersen
Sent: Wednesday, August 30, 2006 2:30 AM
To: Steve Ebersole; hibernate-dev(a)lists.jboss.org
Subject: Re: [hibernate-dev] Connection proxying
Since the intention is to provide a safer execution for the user then
+1,
but if you are going to do this then i guess session.connection() will
still be ok
since it will just be proxied.
btw. your example is a bit simplified since when hibernate runs inside
an
appserver
the user will normally also have to cast through the appservers
"proxying".
( ( OracleConnection ) (( AppServerConnection ) ( HibernateConnection )
connection ).getWrappedConnection()
).getNativeConnection()).doSomethingOracleSpecific()
...but I guess we will then soon see NativeJdbcExtractorAdapter
implementation for Hibernate ;)
/max
> This is in regards to the JDBC interaction code I recently committed
> into the sandbox in SVN.
>
> I am considering proxying the JDBC connections specifically for the
> purpose of auto-registering "subordinate objects" (result sets and
> statements) for automatic cleanup. Currently the registration is a
> manual process in order to take advantage of the automatic cleanup
(have
> a look at org.hibernate.jdbc4.jdbc.impl.BasicWorkTest for the basic
> usage pattern). Specifically what I am thinking is taking a page from
> how app servers implement Connection handles in relation to data
> sources:
>
> public interface HibernateConnection extends java.sql.Connection {
> public Connection getWrappedConnection();
> }
>
> Of course this makes it more difficult for anyone depending on casting
> to a particular driver's Connection impl at some point. But,
> considering that this is atypical usage, my thought was to treat it as
> the more complex use-case; and since this generally requires casting
> anyway, one extra cast and "extraction" is not that big of a deal to
me.
> For example, to get an oracle connection (for LOB handling for
example):
> ( ( OracleConnection ) connection ).doSomethingOracleSpecific() -> ( (
> OracleConnection ) ( ( HibernateConnection ) connection
> ).getWrappedConnection() ).doSomethingOracleSpecific()
>
> Plus, would potentially allow for some other niceties like automatic
> statement logging (perhaps even with parameter replacement).
>
> Thoughts?
>
> _______________________________________________
> hibernate-dev mailing list
> hibernate-dev(a)lists.jboss.org
> https://lists.jboss.org/mailman/listinfo/hibernate-dev
--
--
Max Rydahl Andersen
callto://max.rydahl.andersen
Hibernate
max(a)hibernate.org
http://hibernate.org
JBoss a division of Red Hat
max.andersen(a)jboss.com
17 years, 8 months
Connection proxying
by Steve Ebersole
This is in regards to the JDBC interaction code I recently committed
into the sandbox in SVN.
I am considering proxying the JDBC connections specifically for the
purpose of auto-registering "subordinate objects" (result sets and
statements) for automatic cleanup. Currently the registration is a
manual process in order to take advantage of the automatic cleanup (have
a look at org.hibernate.jdbc4.jdbc.impl.BasicWorkTest for the basic
usage pattern). Specifically what I am thinking is taking a page from
how app servers implement Connection handles in relation to data
sources:
public interface HibernateConnection extends java.sql.Connection {
public Connection getWrappedConnection();
}
Of course this makes it more difficult for anyone depending on casting
to a particular driver's Connection impl at some point. But,
considering that this is atypical usage, my thought was to treat it as
the more complex use-case; and since this generally requires casting
anyway, one extra cast and "extraction" is not that big of a deal to me.
For example, to get an oracle connection (for LOB handling for example):
( ( OracleConnection ) connection ).doSomethingOracleSpecific() -> ( (
OracleConnection ) ( ( HibernateConnection ) connection
).getWrappedConnection() ).doSomethingOracleSpecific()
Plus, would potentially allow for some other niceties like automatic
statement logging (perhaps even with parameter replacement).
Thoughts?
17 years, 8 months
