JSR 354 - Money and Currency
by Steve Ebersole
So it sounds like JSR 354 may not be included in Java 9. Do we still want
to support this for ORM 5? I am not sure if "moneta" requires Java 9...
8 years, 9 months
Re: [hibernate-dev] HHH-6726 LONG and LONG RAW column types in Oracle
by Łukasz Antoniak
Currently Oracle supports database versions from 10.1 to 11.2 [1]. LONG
and LONG RAW data types are deprecated since version 8 and 8i (released
before September 2000) [2]. Oracle keeps those column types only for
backward compatibility [3].
I tried the following scenario (Oracle 10gR2):
1. Create schema with "hibernate.hbm2ddl.auto" set to "create". The LONG
column is created.
2. Insert some data.
3. Modify Oracle dialect as Gail suggested. Avoid setting
"hibernate.hbm2ddl.auto".
4. Insert some data.
To my surprise the test actually passed :). However, I think that we
cannot guaranty the proper behavior in every situation.
As for performance, ImageType is extracted by calling
ResultSet.getBytes() method, which fetches all data in one call [4]. I
don't suppose a major performance difference when data is streamed in
another call. oracle.jdbc.driver.LongRawAccessor.getBytes also fetches
data by reading the stream.
The bug reading LONG column affects JDBC drivers since version 10.2.0.4.
I think that we have to choose between:
- changing Oracle10gDialect. Make a not about it in migration guide to
4.0 and update "5.2.2. Basic value types" chapter in Hibernate
documentation.
- introducing Oracle11gDialect. It can sound weird to access Oracle 10g
database with Oracle 11g dialect.
- disabling execution of Hibernate tests that fail because of this issue
with @SkipForDialect (and maybe develop another version of them with
CLOBs and BLOBs, @RequiresDialect). Hibernate is written correctly
according to "Default Mappings Between SQL Types and Java Types"
(referenced earlier by Gail) and this is more Oracle's JDBC
implementation issue. This option came to my mind, but it's weird :P.
I would vote for the first option.
Regards,
Lukasz Antoniak
[1]
http://www.oracle.com/us/support/library/lifetime-support-technology-0691...
(page 4)
[2]
http://download.oracle.com/docs/cd/A91202_01/901_doc/server.901/a90120/ch...
[3]
http://download.oracle.com/docs/cd/B28359_01/server.111/b28318/datatype.htm
[4] "Getting a LONG RAW Data Column with getBytes"
http://download.oracle.com/docs/cd/B19306_01/java.102/b14355/jstreams.htm
Strong Liu pisze:
> I think oracle 11g is the only one supported DB version by oracle, can we just introduce a new oracle dialect with suggested changes, and deprecate all other existed oracle dialects? this won't affects users app
>
> -----------
> Strong Liu <stliu(a)hibernate.org>
> http://hibernate.org
> http://github.com/stliu
>
> On Oct 15, 2011, at 11:14 AM, Scott Marlow wrote:
>
>> How does this impact existing applications? Would they have to convert
>> LONGs to CLOBs (and LONGRAWs to BLOBs) to keep the application working?
>>
>> As far as the advantage of CLOB over TEXT, if you read every character,
>> which one is really faster? I would expect TEXT to be a little faster,
>> since the server side will send the characters before they are asked
>> for. By faster, I mean from the application performance point of view. :)
>>
>> Could this be changed in a custom Oracle dialect? So new
>> applications/databases could perhaps use that and existing applications
>> might use LONGs a bit longer via the existing Oracle dialect.
>>
>> On 10/14/2011 09:22 PM, Gail Badner wrote:
>>> In [1], I am seeing the following type mappings:
>>>
>>> Column type: LONG -> java.sql.Types.LONGVARCHAR -> java.lang.String
>>> Column type: LONGRAW -> java.sql.Types.LONGVARBINARY -> byte[]
>>>
>>> org.hibernate.type.TextType is consistent with the mapping for LONG.
>>>
>>> org.hibernate.type.ImageType is consistent with the mapping for LONGRAW.
>>>
>>> From this standpoint, the current settings are appropriate.
>>>
>>> I understand there are restrictions when LONG and LONGRAW are used and I see from your other message that there is Oracle documentation for migrating to CLOB and BLOB.
>>>
>>> I agree that changing column type registration as follows (for Oracle only) should fix this:
>>> registerColumnType( Types.VARBINARY, 2000, "raw($l)" );
>>> registerColumnType( Types.VARBINARY, "blob" );
>>>
>>> registerColumnType( Types.LONGVARCHAR, "clob" );
>>> registerColumnType( Types.LONGVARBINARY, "blob" );
>>>
>>> registerColumnType( Types.VARCHAR, 4000, "varchar2($l char)" );
>>> registerColumnType( Types.VARCHAR, "clob" );
>>>
>>> Steve, what do you think? Is it too late to make this change for 4.0.0?
>>>
>>> [1] Table 11-1 of Oracle® Database JDBC Developer's Guide and Reference, 11g Release 1 (11.1) (http://download.oracle.com/docs/cd/B28359_01/java.111/b31224/datacc.htm#g...)
>>> [2] Hibernate Core Migration Guide for 3.5 (http://community.jboss.org/wiki/HibernateCoreMigrationGuide35)
>>> [3] Table 2-10 of Oracle® Database SQL Language Reference
>>> 11g Release 1 (11.1) (http://download.oracle.com/docs/cd/B28359_01/server.111/b28286/sql_elemen...)
>>>
>>> ----- Original Message -----
>>>> From: "Łukasz Antoniak"<lukasz.antoniak(a)gmail.com>
>>>> To: hibernate-dev(a)lists.jboss.org
>>>> Sent: Thursday, October 13, 2011 12:50:13 PM
>>>> Subject: [hibernate-dev] HHH-6726 LONG and LONG RAW column types in Oracle
>>>>
>>>> Welcome Community!
>>>>
>>>> I have just subscribed to the list and wanted to discuss HHH-6726
>>>> JIRA
>>>> issue.
>>>>
>>>> Gail Badner wrote
>>>> (http://lists.jboss.org/pipermail/hibernate-dev/2011-October/007208.html):
>>>> HHH-6726 (Oracle : map TextType to clob and ImageType to blob)
>>>> https://hibernate.onjira.com/browse/HHH-6726
>>>> There have been a number of issues opened since the change was made
>>>> to
>>>> map TextType (LONGVARCHAR) 'long' and ImageType (LONGVARBINARY) to
>>>> 'long
>>>> raw'. This change was already documented in the migration notes.
>>>> Should
>>>> the mapping for Oracle (only) be changed back to clob and blob?
>>>>
>>>> HHH-6726 is caused by an issue in Oracle JDBC driver (version
>>>> 10.2.0.4
>>>> and later). This bug appears when LONG or LONG RAW columns are
>>>> accessed
>>>> not as first or last while processing SQL statement.
>>>>
>>>> I have discussed the topic of mapping TextType to CLOB and ImageType
>>>> to
>>>> BLOB (only in Oracle dialect) with Strong Liu. Reasons for doing so:
>>>> - Oracle allows only one LONG / LONG RAW column per table. This might
>>>> be
>>>> the most important from Hibernate's perspective.
>>>> - LONG / LONG RAW - up to 2 GB, BLOB / CLOB - up to 4 GB.
>>>> - In PL/SQL using LOBs is more efficient (random access to data).
>>>> LONG
>>>> only sequential.
>>>> - LONG and LONG RAW are deprecated.
>>>>
>>>> What is your opinion?
>>>>
>>>> Regards,
>>>> Lukasz Antoniak
>>>> _______________________________________________
>>>> hibernate-dev mailing list
>>>> hibernate-dev(a)lists.jboss.org
>>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>>>>
>>> _______________________________________________
>>> hibernate-dev mailing list
>>> hibernate-dev(a)lists.jboss.org
>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>> _______________________________________________
>> hibernate-dev mailing list
>> hibernate-dev(a)lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/hibernate-dev
>
8 years, 9 months
Search DSL expectations for "keyword()" clause
by Sanne Grinovero
Assuming you build a Lucene Query the following way:
queryBuilder.keyword().onField( "age" ).matching( 5 ).createQuery();
What is your expectation, if the "age" field is being indexed as a NumericField?
Thanks,
Sanne
8 years, 11 months
HQL and spatial
by Steve Ebersole
Karel, etal
We have discussed spatial-specific extensions to HQL for quite some time.
But those discussions have always been kind of esoteric ("boy wouldn't it
be nice to have some spatial support in HQL").
As we are working on redesigning the parsing and interpretation of HQL
queries and since spatial has been integrated upstream, it seems like a
great time to discuss specifics of what this might mean.
I have never used spatial data, let alone crafted queries using spatial
data. So I am not the best driver here.
What kinds of things make sense to add to HQL for supporting spatial
queries?
9 years
Hibernate5 migration
by Koen Serneels
Hi,
I'm migrating from Hibernate4 to 5(RC4). While doing so I'm stumbling on
some stuff that has been removed or moved.
- In Hibernate4 we modified mappings on-the-fly by overriding Spring's
LocalSessionFactoryBean#buildSessionFactory.
Doing so we could first access the getClassMapping on
org.hibernate.cfg.Configuration before letting the SF actually build.
However, in Hibernate5 the metadata access has been refactored and is no
longer part of the Configuration. Should we use MetadataContributor instead
for these purposes?
- Is there a way to register MetadataContributor dynamically? I see that it
is being loaded using Java's ServiceLoader.
However, I need some programmatic API access to enable or disable the
Contributor (for example based on Spring profiles).
- For JTA integration we were using
org.hibernate.engine.transaction.internal.jta.CMTTransactionFactory, but
this class is no longer present.
Also in org.hibernate.cfg.AvailableSettings the key that was used
(hibernate.transaction.factory_class) to configure the factory is also
removed.
Is hibernate.transaction.coordinator_class the new key we should be using
instead with
org.hibernate.resource.transaction.backend.jta.internal.JtaTransactionCoordi
natorImpl as value for JTA?
Do we need to configure anything special in case of resource local TX or is
JdbcResourceLocalTransactionCoordinatorImpl the default?
- generateDropSchemaScript and generateSchemaCreationScript have been
removed from Configuration. Is there a way to access this in another way?
Thanks
Koen.
9 years
Hibernate ORM SQL generation
by Steve Ebersole
We've had a few discussions about this in the past. As 5.0 is getting
close to Final (next week), its time to start contemplating our next major
tasks. The consensus pick for that has been the idea of a "unified SQL
generation engine" along with a shared project for the semantic analysis of
HQL/JPQL (and recently it was decided to include JPA Criteria
interpretation here as well).
The central premise is this. Take the roughly 6 or 7 different top-level
ways Hibernate generates SQL and combine that into one "engine" based on
the input of a "semantic tree". The mentioned HQL/JPQL/Criteria shared
project will be one producer of such semantic trees. Others would include
persisters (for insert/update/delete requests) and loaders (for load
requests).
We have a lot of tasks for this overall goal still remaining.
We still have to finalize the design for the HQL/JPQL/Criteria to semantic
tree translator. One option is to proceed with the Antlr 4 based approach
I started a PoC for. John has been helping me some lately with that. The
first task here is to come to a consensus whether Antlr 4 is the way we
want to proceed here. We've been over the pros and cons before in detail.
In summary, there is a lot to love with Antlr 4. Our grammar for HQL
recognition and semantic tree building is very simple and elegant imo. The
drawback is clearly the lack of tree walking, meaning that we are
responsible for writing by hand our walker for the semantic tree. In fact
multiple, since each consumer (orm, ogm, search) would need to write their
own. And if we decide to build another AST while walking the semantic
tree, we'd end up having to hand-write yet another walker for those.
What I mean by that last part is that there are 2 ways we might choose to
deal with the semantic tree. For the purpose of discussion, let's look at
the ORM case. The first approach is to simply generate the SQL as we walk
the semantic tree; this would be a 2 phase interpretation approach (input
-> semantic tree -> SQL). That works in many cases. However it breaks
down in other cases. This is exactly the approach our existing HQL
translator uses. The other approach is to use a 3-phase translation (input
-> semantic-tree -> semantic-SQL-tree(s) -> SQL). This gives a hint to one
of the major problems. One source "semantic" query will often correspond
to multiple SQL queries; that is hard to manage in the 2-phase approach.
And not to mention integrating things like follow-on fetches and other
enhancements we want to gain from this. My vote is definitely for 3 or
more phases of interpretation. The problem is that this is exactly where
Antlr 4 sort of falls down.
So first things first... we need to decide on Antlr 3 versus Antlr 4
(versus some other parser solution).
Next, on the ORM side (every "backend" can decide this individually) we
need to decide on the approach for semantic-tree to SQL translation, which
somewhat depends on the Antlr 3 versus Antlr 4 decision.
We really need to decide these things ASAP and get moving on them as soon
as ORM 5.0 is finished.
Also, this is a massive undertaking with huge gain potentials for not just
ORM. As such we need to understand who will be working on this. Sanne,
Gunnar... I know y'all have a vested interest and a desire to work on it.
John, I know the same is true for you. Andrea? Have you had a chance to
look over the poc and/or get more familiar with Antlr?
9 years, 2 months
SQM - initial UPDATE/DELETE support
by Steve Ebersole
Just a heads up that I added initial support for UPDATE/DELETE statements
this weekend. I am not happy with the way the "root from element" is
modeled in UPDATE/DELETE statements, and especially the wide difference
with how they work with SelectStatement and FromClause. I plan to do some
more work there.
I think part of that is to move away from using a concrete FromClause as
the base for the "stack", instead leveraging a contract more like
FromElementSpace and something like a FromElementContainer (FromClause
would be one such container, so would a UpdateStatement and a
DeleteStatement). Still brainstorming the specifics at the moment.
9 years, 2 months
