Ofc. Vlad was saying the same. More what we discussed today though was what to do with the API Type stuff (o.h.type versus o.h.type.spi).
On Tue, Jan 24, 2017 at 5:52 PM Christian Beikov <christian.bei...@gmail.com> wrote: > Sounds like what we have discussed today and as far as I can remember, > nobody complained about removing the type spi stuff. I think we might want > to prepare a blog post or topical/migration guide that helps people to > migrate their custom types to the new way of doing it. > > > Am 23.01.2017 um 18:37 schrieb Steve Ebersole: > > What is everyone's opinion of the following sections? > > <snip> > There are some things we should discuss too in terms of user impact. We > know up front that we need to move to reading values from JDBC ResultSets > positionally, as opposed to nominally which is how it was exposed in > Hibernate prior to 6.0. So we know already we will be asking implementors > and consumers of those contracts to make changes. Given that, we have > *some* liberty in changing these contracts some more. We just want to be > cognizant of (a) how much we change, (b) who it affects (use cases) and (c) > whether there are alternatives. For any use cases we determine to be > "valid" use cases, I think we need to make certain that there is some way > to handle that in the new alternatives. > > One use case, e.g., is setting Query parameters and being able to specify > its Type. To a degree we want to be able to continue to support that. But > I think we limit it to just references to org.hibernate.type.Type (though > "gutted") specifically and remove all others; and temporarily have the new > org.hibernate.type.spi.Type interface extend the old. This would allow > them to continue to get these org.hibernate.type.Type references in some > fashion and use them as Query parameter type hints. But I think we should > look at implementing some other parameter type "hints" like accepting > PersistentAttribute/Navigable references, JPA (static) metamodel > references, etc. These are better, as they would include things like > AttributeConverter whereas the Type reference would not. > </snip> > > > On Mon, Jan 23, 2017 at 11:13 AM Christian Beikov < > christian.bei...@gmail.com> wrote: > > Since custom JavaTypeDescriptors and SqlTypeDescriptors can be used > instead, I'm also for removing it. > > Am 23.01.2017 um 15:45 schrieb andrea boriero: > > trying to find a valid reason to keep UserType but not able, so I'm for > > removing it. > > > > On 23 January 2017 at 14:36, Vlad Mihalcea <mihalcea.v...@gmail.com> > wrote: > > > >> Hi, > >> > >> I see no reason why we should keep it indefinitely. I'd say we > deprecate it > >> in 5.x, and remove it later (6.0 or 6.1). > >> Migrating a custom UserType to using Java and SQL descriptor is not > >> difficult, and we could just write a blog post for a step-by-step guide. > >> > >> Anyone in favor of keeping UserType? > >> > >> Vlad > >> > >> On Mon, Jan 23, 2017 at 4:11 PM, Steve Ebersole <st...@hibernate.org> > >> wrote: > >> > >>> Nice! > >>> > >>> So if we keep UserType, we have to be clear that it has to change. I > >> also > >>> do not want to continue to support the other "user type extensions", > >> like: > >>> > >>> 1. org.hibernate.usertype.EnhancedUserType > >>> 2. org.hibernate.usertype.DynamicParameterizedType > >>> 3. org.hibernate.usertype.LoggableUserType > >>> 4. etc > >>> > >>> So we should come up with a plan for that. > >>> > >>> > >>> On Mon, Jan 23, 2017, 1:48 PM Vlad Mihalcea <mihalcea.v...@gmail.com> > >>> wrote: > >>> > >>> Hi, > >>> > >>> I like the SqlTypeDescriptor and JavaTypeDescriptor much better than > >>> UserType, which we should probably deprecate in 6.0. > >>> > >>> I wrote an article on my blog in which I demonstrate how to create a > JSON > >>> type using JavaTypeDescriptor and SqlTypeDescriptor: > >>> > >>> https://vladmihalcea.com/2016/06/20/how-to-map-json-objects- > >>> using-generic-hibernate-types/ > >>> > >>> I like this example because it shows how you can reuse the same > >>> JavaTypeDescriptor for two different JSON SQL types: String or Binary, > >>> for which we have two distinct SqlTypeDescriptor objects. > >>> > >>> The new User Guide shows ho to implement Custom Types using the Java > and > >>> SQL descriptors as well: > >>> > >>> http://docs.jboss.org/hibernate/orm/5.2/userguide/ > >>> html_single/Hibernate_User_Guide.html#basic-custom-type > >>> > >>> Vlad > >>> > >>> On Mon, Jan 23, 2017 at 3:37 PM, Steve Ebersole <st...@hibernate.org> > >>> wrote: > >>> > >>> Right, and that exactly lines up with what I am proposing. > >>> > >>> If the intent of "customize" is to describe new Java types (e.g. Java 8 > >>> temporals prior to our explicit support) the tht is the role of a > >>> JavaTypeDescriptor, specifically a BasicJavaDescriptor. They would > >>> register a BasicJavaDescriptor describing the type. > >>> > >>> If the intent is to model a non-supported SQL type then that would mean > >>> adding a new SqlTypeDescriptor describing that type, although that will > >>> often also mean adding a new BasicJavaDescriptor describing the Java > >>> mapping of that SQL type. > >>> > >>> > >>> On Mon, Jan 23, 2017 at 7:00 AM Vlad Mihalcea <mihalcea.v...@gmail.com > > > >>> wrote: > >>> > >>> Hi, > >>> > >>> Related to your questions: > >>> > >>> he main thing I wonder about is what we mean by "custom > >>> types" in terms of what exactly is being customized? And how does that > >>> relate specifically to BasicType versus EmbeddedType versus ...? > >>> > >>> > >>> Most of the time, the users want to take advantage of various database > >>> types that are not universally supported by all RDBMS: JSON, Money (SQL > >>> Server). > >>> > >>> On the Java side, I don't see what we can customize because we already > >>> provide all the basic types, and for everything else, users can compose > >>> those into Embeddables. The Java 1.8 Date/Time are an example of what > >> users > >>> would like to customize in case we didn't support this already. But > even > >> if > >>> Java 1.9 adds other basic types, chances are that we are going to > support > >>> them natively, meaning that users will still not need to add a custom > >> Type. > >>> So, I don't see how a Hibernate user will customize the way > Embeddables, > >>> Enums, Entities or Collections are being stored or loaded from the > >>> database. The exception to the rule is a recent Pull Request from > someone > >>> who wants to support PostgreSQL arrays. But this falls back into the > same > >>> category as before: database types that are not universally supported > by > >>> all RDBMS. > >>> > >>> Vlad > >>> > >>> On Thu, Jan 19, 2017 at 9:55 PM, Vlad Mihalcea < > mihalcea.v...@gmail.com> > >>> wrote: > >>> > >>> There's a lot to dig in here. I'll have to get the branch and study the > >>> changes, to come back with some opinions. > >>> > >>> Vlad > >>> > >>> On Thu, Jan 19, 2017 at 7:34 PM, Steve Ebersole <st...@hibernate.org> > >>> wrote: > >>> > >>> We are getting pretty far along on the 6.0 changes and I wanted to > start > >>> a(nother) discussion about Types in 6.0 to get feedback and thoughts > on a > >>> few topics. > >>> > >>> First a quick break down of JavaTypeDescriptors, SqlTypeDescriptors, > >> Types > >>> and "persisters"... > >>> > >>> (a lot of this is the same from pre-6.0, just making things more > >> explicit) > >>> JavaTypeDescriptors and SqlTypeDescriptors are the "lowest level", so > >> let's > >>> start there. A JavaTypeDescriptor is a descriptor of a given Java > type. > >>> That is, it provides Hibernate with information about the Java type. > Is > >> it > >>> a numeric type? How do we compare 2 values of this type? How do we > >> make a > >>> deep copy of a value of this type? Etc. SqlTypeDescriptor is the > same, > >>> but for a database type (VARCHAR, BLOB, etc). These 2 work together to > >>> perform reading and writing at the JDBC-level. > >>> > >>> We decided to broadly categorize JavaTypeDescriptors based on the JPA > >> type > >>> categorizations: > >>> > >>> 1. BASIC - BasicJavaDescriptor > >>> 1. TemporalJavaDescriptor > >>> 2. NumericJavaDescriptor > >>> 2. MANAGED - ManagedJavaDescriptor > >>> 1. EMBEDDABLE - EmbeddableJavaDescriptor > >>> 2. IDENTIFIABLE - IdentifiableJavaDescriptor > >>> 1. MAPPED_SUPERCLASS - MappedSupercassJavaDescriptor > >>> 2. ENTITY - EntityJavaDescriptor > >>> > >>> > >>> Type (org.hibernate.type.spi.Type) represents a combination of a > >>> JavaTypeDescriptor and one or more SqlTypeDescriptors in relation to a > >>> specific "non-root Navigable domain value". Navigable is a > query-focused > >>> contract (SQM/HQL/Criteria) so I wont get too deep into that here. At > a > >>> high-level t is similar to JPA's Bindable except that it applies to > >>> Collection indices (or map-keys) and elements (or map-values) as well. > >>> Navigable essentially represents an named navigation one can perform > in a > >>> query. The root Navigable is always an entity (EntityPersister). > >>> EntityPersister is the only Navigable that does not expose a Type. > >> (There > >>> is an EntityType, but it represents entity-valued non-root Navigables > >> such > >>> as a ManyToOne). All other navigables expose a Type. That is all a > >>> long-winded way to say that Types represents that > Java/SqlTypeDescriptors > >>> for a role-based Navigable. > >>> > >>> Like the categorization discussed above for JavaTypeDescriptor, Type > has > >> a > >>> similar categorization: > >>> > >>> 1. Type > >>> 1. BasicType > >>> 1. TemporalType > >>> 2. AnyType > >>> 3. ManagedType > >>> 1. EmbeddedType > >>> 2. IdentifiableType > >>> 1. MappedSuperclassType > >>> 2. EntityType > >>> > >>> It is important to keep in mind that these represents a specific > >> reference > >>> to thse things in regards to a Navigable. E.g. an EntityType is the > >> "type" > >>> of a SingularPersistentAttribute that is a ManyToOne - it points to the > >>> corresponding EntityPersister but it also represents the FK columns to > >>> refer to the entity. It is a role-based Navigable. > >>> > >>> Historically reads and writes have all routed through the Type (with > >>> certain Types delegating much of that to persisters). That will no > >> longer > >>> be the case in 6.0 as one of the main design goals for 6.0 is to > re-write > >>> how Hibernate reads and writes (mainly reads) values from JDBC. The > >> major > >>> shift here is to read all values from JDBC using a "SqlSelectionReader" > >>> equivalent to a BasicType. These values are read and held in an array > >> that > >>> "readers" then know how to access (positionally) and use. Most of that > >>> design is beyond the discussion here, but it useful to understand. It > is > >>> discussed in the design.adoc in my orm-sqm poc repo for those curious. > >>> Long story, short... Types no longer directly implement JDBC read/write > >>> which we will come back to later. > >>> > >>> PersistentAttribute and the other Navigables now take a role in JDBC > >>> reads/writes. AttributeConverters and other read/write-related > concerns > >>> have been moved to these contracts. Again, most of this is covered in > >> the > >>> mentioned design doc. > >>> > >>> Since Type no longer directly implements JDBC read/write operations I > >> think > >>> it is important to ask ourselves what exactly we see as "customizable" > >> wrt > >>> each Type. Is that different for each category, or the same across all > >>> Type categories? E.g. I know of no customization of EntityType as it > >>> exists in 5.x, and tbh I am not even sure what that would mean. > >> BasicType > >>> obviously has some parts that we want to allow users to override, but > is > >>> that really best achieved through a custom BasicType? Or is it better > >>> served by allowing custom JavaTypeDescriptor/SqlTypeDescriptor and/or > >>> SqlSelectionReader? What about EmbeddedType? CollectionType? This > >> would > >>> affect @TypeDef and Type registration methods specific to > customizations. > >>> > >>> Persisters for the most part continue to serve the same role they have > in > >>> the past with a few additions and some changes... > >>> > >>> One addition was the creation of an EmbeddedPersister. *Embedded*. > >> This, > >>> like CollectionPersister, models a "role" e.g. "Person.name" as opposed > >> to > >>> the Embeddable Name.class. Note however that JPA calls it an > >>> EmbeddableType and expects info about the Embeddable (the Class). > >>> EmbeddedPersister is role-based (Embedded) instead, which is a > mismatch. > >>> In the case there are more than 1 usage of the Embeddable in different > >>> Embedded roles then we have to decide which EmbeddedPersister to > return. > >>> It affects the sub-Attributes information. We could just return "one > of > >>> them" and deal with it for Alpha1, but we should answer what we want to > >> do > >>> there long term. > >>> > >>> Collectively, these persisters now implement the JPA ManagedType model > >>> directly. Another addition was the creation of ManagedTypeImplementor, > >>> IdentifiableTypeImplementor and MappedSuperclassTypeImplementor in the > >>> persister hierarchy. Which means we can now directly return them in > our > >>> JPA Metamodel impl. > >>> > >>> That also means implementing JPA's notion of Attributes. I also needed > >>> something similar for SQM's Navigable contract. Plus I have been > working > >>> towards changing how Hibernate understands Attributes internally > >>> (encapsulation - OO ftw!) for some time anyway, so this all dove-tailed > >>> well. > >>> > >>> There are some things we should discuss too in terms of user impact. > We > >>> know up front that we need to move to reading values from JDBC > ResultSets > >>> positionally, as opposed to nominally which is how it was exposed in > >>> Hibernate prior to 6.0. So we know already we will be asking > >> implementors > >>> and consumers of those contracts to make changes. Given that, we have > >>> *some* liberty in changing these contracts some more. We just want to > be > >>> cognizant of (a) how much we change, (b) who it affects (use cases) and > >> (c) > >>> whether there are alternatives. For any use cases we determine to be > >>> "valid" use cases, I think we need to make certain that there is some > way > >>> to handle that in the new alternatives. > >>> > >>> One use case, e.g., is setting Query parameters and being able to > specify > >>> its Type. To a degree we want to be able to continue to support that. > >> But > >>> I think we limit it to just references to org.hibernate.type.Type > (though > >>> "gutted") specifically and remove all others; and temporarily have the > >> new > >>> org.hibernate.type.spi.Type interface extend the old. This would allow > >>> them to continue to get these org.hibernate.type.Type references in > some > >>> fashion and use them as Query parameter type hints. But I think we > >> should > >>> look at implementing some other parameter type "hints" like accepting > >>> PersistentAttribute/Navigable references, JPA (static) metamodel > >>> references, etc. These are better, as they would include things like > >>> AttributeConverter whereas the Type reference would not. > >>> > >>> Sorry this got so long. I've had a lot floating around in my head the > >> last > >>> few days as I have worked on 6.0 and I wanted to bring them up for > >>> discussion. The main thing I wonder about is what we mean by "custom > >>> types" in terms of what exactly is being customized? And how does that > >>> relate specifically to BasicType versus EmbeddedType versus ...? > >>> _______________________________________________ > >>> hibernate-dev mailing list > >>> hibernate-dev@lists.jboss.org > >>> https://lists.jboss.org/mailman/listinfo/hibernate-dev > >>> > >>> > >>> > >>> > >>> > >> _______________________________________________ > >> hibernate-dev mailing list > >> hibernate-dev@lists.jboss.org > >> https://lists.jboss.org/mailman/listinfo/hibernate-dev > >> > > _______________________________________________ > > hibernate-dev mailing list > > hibernate-dev@lists.jboss.org > > https://lists.jboss.org/mailman/listinfo/hibernate-dev > > _______________________________________________ > hibernate-dev mailing list > hibernate-dev@lists.jboss.org > https://lists.jboss.org/mailman/listinfo/hibernate-dev > > > _______________________________________________ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
