I am not sure how practical that is. The goal of this is to allow things that are not known in advance to be connected. I think you are thinking of composing objects from pieces of other objects. As a general practice in designing EOs, I think that would have negative performance impacts. And I suspect that everyone would want something slightly different.
Chuck On 2012-09-20, at 8:25 PM, Johnny Miller wrote: > It would be cool, if like erprototypes, there was a framework that had a set > of partial entities that you could use as a baseline for your models. > > Johnny Miller > Kahalawai Media Co. > > On Sep 20, 2012, at 4:56 PM, Chuck Hill <ch...@global-village.net> wrote: > >> It is probably time to remove this from the package docs: >> >> * PARTIAL ENTITIES SHOULD BE CONSIDERED EXPERIMENTAL * >> >> This is some awesome coolness from Mike Schrag. People should be using this. >> >> >> Chuck >> >> >> On 2012-09-20, at 7:36 PM, David Aspinall wrote: >> >>> Hi All, >>> >>> I was recently sponsored in a review of the ERXPartial package from >>> ERExtensions by the very nice folks at Logic Squad >>> (http://logicsquad.net/). They have authorized me to release everything >>> into Wonder with the hope the ERXPartial package will be further developed >>> and attract interest among the community. >>> >>> Currently the example code and reports are available in the integration >>> branch of wonder. There is also the review document ERXPartials Review >>> v1.1.html with my notes and thoughts prior to performing any development or >>> tests against the partials package. >>> >>> For those who are unfamiliar with the partials package, the original >>> package documentation from Mike Schrag contained this overview >>> >>> http://jenkins.wocommunity.org/job/Wonder/javadoc/er/extensions/partials/package-summary.html >>> >>> Partial Entities provide a mechanism for defining a single entity whose >>> definition spans across multiple EOModels along with tools to interact with >>> these partial definitions in a type-safe way. >>> >>> Partial entities are specifically designed to allow reuse and extension of >>> existing models. A very common case where this becomes useful is that of a >>> Person entity. Person is an entity that is used in many different >>> scenarios, each of which requires additional attributes and relationships. >>> For instance, you may have a task management application and you want to >>> embed your calendaring framework into it. The common Person base entity may >>> have "username" and "password" attributes, the tasking application may add >>> an "activeTasks" relationship, and the calendaring framework may add a >>> "scheduledEvents" relationship as well as "dayStartTime" and "dayEndTime" >>> attributes. Note that partials are not designed to address the issue of >>> "roles," where different people in the system may have different roles at >>> different times. Partial entities are designed to address the issue of >>> combining high level modules together to form more complex static entity >>> declarations. >>> >>> >>> >>> ERXPartials Test / Example >>> Notes about ERXPartials >>> Design Overview >>> >>> • ERXPartialBaseModel contains a very basic model containing the Root >>> entity for the partials named Person. >>> >>> • contains one standard relationship to GenderType >>> • contains a standard migration to create the initial tables for the >>> Person and GenderType >>> • the migration also preloads some default values for gender and 100 >>> semi-random Person records. >>> • ERXPartialExampleModel contains additional extensions to the Person >>> entity. The design uses two partial entities. >>> >>> • one partial entity Partial_AuthenticatedPerson stores the basic >>> authenticated user details username, password and lastLoginDate >>> • the second entity Partial_EmployeePerson stores common employee >>> details like department, employeeType, salary and employeeNumber >>> • Company, Department and EmployeeType provide additional >>> relationships for the Partial_EmployeePerson >>> • the migration in this frameworks creates the supporting tables in a >>> normal fashion, and adds the additional attributes and constraints to the >>> existing Person table. >>> • ERXPartialExampleApp is a simple D2W demo application to demonstrate >>> and test the Partials in a live environment. >>> >>> Generated Partial entity Templates >>> >>> By default I was using the _WonderEntity.java template, however there was a >>> small issue with the generated content. When the template created a to-Many >>> accessor method, it was using the relationship actual destination entity to >>> generate the appropriate key path. However when the destination is a >>> ERXPartial entity then the actual destination is the Root Entity. In this >>> example the Department relationship to the Partial_EmployeePerson was >>> generated as >>> >>> Bad >>> >>> public NSArray<er.example.erxpartials.model.Person> >>> partial_EmployeePersons(EOQualifier qualifier, NSArray<EOSortOrdering> >>> sortOrderings, boolean fetch) { >>> … >>> EOQualifier inverseQualifier = new >>> EOKeyValueQualifier(er.example.erxpartials.model.Person.DEPARTMENT_KEY, >>> EOQualifier.QualifierOperatorEqual, this); >>> >>> Should be >>> >>> public NSArray<er.example.erxpartials.model.Person> >>> partial_EmployeePersons(EOQualifier qualifier, NSArray<EOSortOrdering> >>> sortOrderings, boolean fetch) { >>> … >>> EOQualifier inverseQualifier = new >>> EOKeyValueQualifier(er.example.erxpartials.model.Partial_EmployeePerson.DEPARTMENT_KEY, >>> EOQualifier.QualifierOperatorEqual, this); >>> >>> A patched _PartialWonderEntity.java is included int the Resources of the >>> ERXPartialExampleModel project, but I think it needs to be moved into >>> WOLips at some point. >>> >>> Validation >>> >>> The original behaviour for validation forwards all messages from the >>> ERXPartial object to all contained partials. The problem is that only one >>> of this partials will correctly validate the specified key path, the other >>> partials will throw exceptions for unbound keys. >>> >>> Additionally when the ERXPartialInitializer merges the partial entities >>> into the Root, the EOEntities for the partials are removed from the >>> EOModel, so it is not possible to query the original partial entity to >>> determine if the key path is valid for that partial object. >>> >>> My solution is currently to generate a static array for the attributes and >>> the relationships and have theERXPartialGenericRecordquery the partial to >>> determine the validity of a given key path before forwarding the invocation. >>> >>> Patches for this are included in the ERXPartial, ERXPartialGenericObject >>> classes and support is also added to the_PartialWonderEntity.java template. >>> >>> Getting Started >>> • create the database. I used Frontbase so the data model would have >>> persistence and Frontbase specifically because it's what I use the most >>> often (so it was the easiest to get up and running). >>> >>> • Change into the ERXPartialBaseModel directory >>> GVCDev:ERXPartialBaseModel daspinall$ ant fb.recreate >>> >>> Buildfile: >>> /Volumes/Data/Development/GitHub/ERXPartials/wonder/Tests/ERXPartials/ERXPartialBaseModel/build.xml >>> >>> init.properties: >>> >>> fb.recreate: [exec] connect to ERXPartials user _system; >>> [exec] Cannot connect to ERXPartials@localhost >>> [exec] Database is not running >>> [exec] stop database; >>> [exec] No current session. >>> [exec] delete database ERXPartials; >>> [exec] Cannot delete database ERXPartials@localhost; >>> [exec] Reason: Database is unknown >>> [exec] create database ERXPartials; >>> [exec] connect to ERXPartials user _system; >>> [exec] Auto committing is on: SET COMMIT TRUE; >>> [exec] create user erxpartial; >>> [exec] set password test user erxpartial; >>> [exec] create schema erxpartial authorization erxpartial; >>> [exec] disconnect all; >>> [exec] >>> >>> BUILD SUCCESSFUL >>> >>> Total time: 1 second >>> >>> GVCDev:ERXPartialBaseModel daspinall$ >>> • compile and run. The main page is a login page, but there is no login >>> logic, just click the button :) >>> >>> David Aspinall >>> Senior IT Consultant >>> Global Village Consulting Inc. >>> E: daspin...@global-village.net >>> >>> >>> _______________________________________________ >>> Do not post admin requests to the list. They will be ignored. >>> Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) >>> Help/Unsubscribe/Update your Subscription: >>> https://lists.apple.com/mailman/options/webobjects-dev/chill%40global-village.net >>> >>> This email sent to ch...@global-village.net >> >> -- >> Chuck Hill Senior Consultant / VP Development >> >> Practical WebObjects - for developers who want to increase their overall >> knowledge of WebObjects or who are trying to solve specific problems. >> http://www.global-village.net/gvc/practical_webobjects >> >> >> >> >> >> >> >> >> >> _______________________________________________ >> Do not post admin requests to the list. They will be ignored. >> Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) >> Help/Unsubscribe/Update your Subscription: >> https://lists.apple.com/mailman/options/webobjects-dev/jlmiller%40kahalawai.com >> >> This email sent to jlmil...@kahalawai.com -- Chuck Hill Senior Consultant / VP Development Practical WebObjects - for developers who want to increase their overall knowledge of WebObjects or who are trying to solve specific problems. http://www.global-village.net/gvc/practical_webobjects _______________________________________________ Do not post admin requests to the list. They will be ignored. Webobjects-dev mailing list (Webobjects-dev@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/webobjects-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
