傳統數據庫的例子(下面降序): 映射hasOne與屬於關聯Grails中
我有一個具有複合主鍵,自動生成ID1作爲SERIAL(1),ID2只有默認值父表。 子表具有完全相同的主鍵,也是父表中的外鍵。
子表類似於「加」表或擴展父表。我們需要PArent表中的其他列,但我們不能更改父表。因此,他們爲我們提供更多信息子表創建的,從父表中添加外鍵子表,也使該組合鍵爲主:)
我嘗試它的Grails這樣映射:
父.groovy作爲
package test
class Parent implements Serializable{
Integer id1
Integer id2
String parentDesc
static hasOne = [child: Child]
static mappedBy = [child: 'parent']
static constraints = {
child nullable:true
}
static mapping = {
table 'parent'
id composite: ['id1', 'id2']
id1 column: 'id1'
id2 column: 'id2'
parentDesc column: 'parent_desc'
}
}
Child.groovy
package test
import java.io.Serializable
class Child implements Serializable{
Integer id1
Integer id2
Parent parent
String childDesc
static belongsTo = [parent: Parent]
static mapping = {
table 'child'
id composite: ['id1', 'id2']
id1 column: 'id1'
id2 column: 'id2'
childDesc column: 'child_desc'
columns {
parent(insertable: false, updateable: false) {
column name: 'id1'
column name: 'id2'
}
}
}
} 父項具有一個或零個子組合鍵id1,id2。子屬於Parent(保存和刪除父項),具有外鍵Parent的主鍵,而且這個組合外鍵也是他的主鍵。當有一些行時,Hibernate不能返回值(空表沒有問題:) - 我認爲它的同一個bug報告了here(但這次已經解決了)。
技術信息: 數據庫:MaxDB的(傳統)也嵌入式
- grailsVersion H2測試= 3.2.9
- 編譯 「org.grails.plugins:hibernate5」
- compile「org.hibernate:hibernate-core:5.1.3.Final」
- compile'org.hi bernate:休眠-java8:5.1.2.Final」
- 編譯 'com.h2database:H2:1.4.193'
- 編譯 「com.sap:sapdbc:7.4.4」
全部測試項目:dropbox
堆棧跟蹤:
[2m2017-06-05 13:59:26.063[0;39m [31mERROR[0;39m [2m---[0;39m [2m[nio-8080-exec-1][0;39m [36mo.g.web.errors.GrailsExceptionResolver [0;39m [2m:[0;39m NullPointerException occurred when processing request: [GET]/
Stacktrace follows:
java.lang.reflect.InvocationTargetException: null
at org.grails.core.DefaultGrailsControllerClass$ReflectionInvoker.invoke(DefaultGrailsControllerClass.java:211)
at org.grails.core.DefaultGrailsControllerClass.invoke(DefaultGrailsControllerClass.java:188)
at org.grails.web.mapping.mvc.UrlMappingsInfoHandlerAdapter.handle(UrlMappingsInfoHandlerAdapter.groovy:90)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at org.springframework.boot.web.filter.ApplicationContextHeaderFilter.doFilterInternal(ApplicationContextHeaderFilter.java:55)
at org.grails.web.servlet.mvc.GrailsWebRequestFilter.doFilterInternal(GrailsWebRequestFilter.java:77)
at org.grails.web.filters.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:67)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.NullPointerException: null
at org.hibernate.persister.entity.AbstractEntityPersister.loadByUniqueKey(AbstractEntityPersister.java:2172)
at org.hibernate.type.EntityType.loadByUniqueKey(EntityType.java:692)
at org.hibernate.type.EntityType.resolve(EntityType.java:434)
at org.hibernate.engine.internal.TwoPhaseLoad.doInitializeEntity(TwoPhaseLoad.java:151)
at org.hibernate.engine.internal.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:125)
at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1139)
at org.hibernate.loader.Loader.processResultSet(Loader.java:998)
at org.hibernate.loader.Loader.doQuery(Loader.java:936)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:342)
at org.hibernate.loader.Loader.doList(Loader.java:2622)
at org.hibernate.loader.Loader.doList(Loader.java:2605)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2434)
at org.hibernate.loader.Loader.list(Loader.java:2429)
at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:109)
at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1787)
at org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:363)
at org.grails.orm.hibernate.query.AbstractHibernateQuery.listForCriteria(AbstractHibernateQuery.java:700)
at org.grails.orm.hibernate.HibernateGormStaticApi$_list_closure1.doCall(HibernateGormStaticApi.groovy:87)
at org.grails.orm.hibernate.GrailsHibernateTemplate.doExecute(GrailsHibernateTemplate.java:286)
at org.grails.orm.hibernate.GrailsHibernateTemplate.execute(GrailsHibernateTemplate.java:230)
at org.grails.orm.hibernate.GrailsHibernateTemplate.execute(GrailsHibernateTemplate.java:116)
at org.grails.orm.hibernate.HibernateGormStaticApi.list(HibernateGormStaticApi.groovy:73)
at org.grails.orm.hibernate.HibernateGormStaticApi.list(HibernateGormStaticApi.groovy:72)
at org.grails.datastore.gorm.GormEntity$Trait$Helper.list(GormEntity.groovy:654)
at test.ParentController.$tt__index(ParentController.groovy:10)
at grails.transaction.GrailsTransactionTemplate$2.doInTransaction(GrailsTransactionTemplate.groovy:96)
at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:133)
at grails.transaction.GrailsTransactionTemplate.execute(GrailsTransactionTemplate.groovy:93)
... 14 common frames omitted
沒有使用相同的設置中的hasMany沒有問題。可能在休眠時出錯? –