1
在我的模型中，我有一個具有多個數據集的批處理，每個數據集有許多文件和一個文件hasMany sourceFiles。 我們檢索數據集也檢索源文件與 一長串選擇，即使我沒有請求sourceFiles，或至少這是我的想法。連接不是懶惰的問題;）
這是我的簡化模型，我刪除了所有非有趣的東西。
class Batch {
static hasMany = [ datasets : Dataset]
}
class Dataset {
File mainFile
Batch batch
static hasMany = [files : File]
static mapping = {
files column:"dataset_id"
files joinTable:[name:"${Constants.phase3DB}${Constants.schemaName}.datasets_files"]
files fetch:'join'
}
}
class File {
static hasMany = [ sourceFiles: String ]
static mapping = {
sourceFiles joinTable: [name:
"${Constants.phase3DB}${Constants.schemaName}.provenance",
key:'product_file', column:'source_file', type:'text']
}
}
這是我在我的服務：
Batch batch = Batch.get(batchId)
def datasets = Dataset.withCriteria {
eq "batch", batch
fetchMode "files", org.hibernate.FetchMode.JOIN
}
batch.datasets = datasets
這樣做我可以看到一個選擇了加入到文件：
select this_.dataset_id as dataset_1_14_1_, this_.active as active2_14_1_, this_.batch_id as batch_id3_14_1_, this_.deprecation_date as deprecat4_14_1_, this_.group_id as group_id5_14_1_, this_.version as version6_14_1_, this_.main_file_id as main_fil7_14_1_, files2_.dataset_id as dataset_1_14_3_, file3_.file_id as file_id2_15_3_, file3_.file_id as file_id1_18_0_, file3_.archive_id as archive_2_18_0_, file3_.archived as archived3_18_0_, file3_.catalog_extracted as catalog_4_18_0_, file3_.category as category5_18_0_, file3_.checksum as checksum6_18_0_, file3_.keywords_extracted as keywords7_18_0_, file3_.name as name8_18_0_, file3_.processing_date as processi9_18_0_, file3_.size as size10_18_0_
from phase3v2.dbo.datasets this_
left outer join phase3v2.dbo.datasets_files files2_ on this_.dataset_id=files2_.dataset_id
left outer join phase3v2.dbo.files file3_ on files2_.file_id=file3_.file_id
where this_.batch_id=?;
但緊接着我看到一個長這樣的查詢列表：
select sourcefile0_.product_file as product_1_18_0_,
sourcefile0_.source_file as source_f2_20_0_ from phase3v2.dbo.provenance
sourcefile0_ where sourcefile0_.product_file=?
正如我說我不需要sourceFiles，但細，讓我們找回它們與一個單一的查詢：
Batch batch = Batch.get(batchId)
def datasets = Dataset.withCriteria {
eq "batch", batch
fetchMode "files", org.hibernate.FetchMode.JOIN
fetchMode "files.sourceFiles", org.hibernate.FetchMode.JOIN
}
batch.datasets = datasets
這樣做我有一個空指針異常。
java.lang.NullPointerException
at
org.hibernate.engine.internal.StatefulPersistenceContext.getLoadedCollectionOwnerOrNull(StatefulPersistenceContext.java:752)
at
org.hibernate.event.spi.AbstractCollectionEvent.getLoadedOwnerOrNull(AbstractCollectionEvent.java:75)
at
org.hibernate.event.spi.InitializeCollectionEvent.<init>(InitializeCollectionEvent.java:36)
at
org.hibernate.internal.SessionImpl.initializeCollection(SessionImpl.java:1895)
at
org.hibernate.collection.internal.AbstractPersistentCollection$4.doWork(AbstractPersistentCollection.java:558)
at
org.hibernate.collection.internal.AbstractPersistentCollection.withTemporarySessionIfNeeded(AbstractPersistentCollection.java:260)
at
org.hibernate.collection.internal.AbstractPersistentCollection.initialize(AbstractPersistentCollection.java:554)
at
org.hibernate.collection.internal.AbstractPersistentCollection.read(AbstractPersistentCollection.java:142)
at
org.hibernate.collection.internal.PersistentSet.hashCode(PersistentSet.java:447)
at org.eso.phase3.rm.File.hashCode(File.groovy)
at java.util.HashMap.hash(HashMap.java:338)
at java.util.HashMap.put(HashMap.java:611)
at java.util.HashSet.add(HashSet.java:219)
at java.util.AbstractCollection.addAll(AbstractCollection.java:344)
at
org.hibernate.collection.internal.PersistentSet.endRead(PersistentSet.java:344)
at
org.hibernate.engine.loading.internal.CollectionLoadContext.endLoadingCollection(CollectionLoadContext.java:251)
at
org.hibernate.engine.loading.internal.CollectionLoadContext.endLoadingCollections(CollectionLoadContext.java:238)
at
org.hibernate.engine.loading.internal.CollectionLoadContext.endLoadingCollections(CollectionLoadContext.java:211)
at org.hibernate.loader.Loader.endCollectionLoad(Loader.java:1156)
at
org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1125)
at org.hibernate.loader.Loader.processResultSet(Loader.java:972)
at org.hibernate.loader.Loader.doQuery(Loader.java:920)
at
org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:354)
at org.hibernate.loader.Loader.doList(Loader.java:2553)
at org.hibernate.loader.Loader.doList(Loader.java:2539)
at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2369)
at org.hibernate.loader.Loader.list(Loader.java:2364)
at
org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:126)
at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1682)
at org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:380)
at
org.grails.datastore.gorm.GormStaticApi$_withCriteria_closure11.doCall(GormStaticApi.groovy:305)
at
org.springsource.loaded.ri.ReflectiveInterceptor.jlrMethodInvoke(ReflectiveInterceptor.java:1270)
at com.sun.proxy.$Proxy47.doInSession(Unknown Source)
at
org.grails.datastore.mapping.core.DatastoreUtils.execute(DatastoreUtils.java:302)
at
org.grails.datastore.gorm.AbstractDatastoreApi.execute(AbstractDatastoreApi.groovy:37)
at
org.grails.datastore.gorm.GormStaticApi.withCriteria(GormStaticApi.groovy:304)
at org.eso.phase3.rm.Dataset.withCriteria(Dataset.groovy)
at org.eso.phase3.rm.Dataset$withCriteria.call(Unknown Source)
at ConsoleScript0.run(ConsoleScript0:4)
at
org.springsource.loaded.ri.ReflectiveInterceptor.jlrMethodInvoke(ReflectiveInterceptor.java:1270)
我真的不知道發生了什麼事情。任何想法？
條件中的文件抓取：'join''在域類和'fetchMode「文件中，org.hibernate.FetchMode.JOIN'將始終導致對相關結果的急切抓取。如果你想加入懶惰，你需要在領域類中獲取：'SELECT''（如果沒有指定，這是默認行爲），'fetchMode'作爲SELECT。請參閱[fetch]的文檔（https://grails.github.io/grails-doc/3.0.x/ref/Database%20Mapping/fetch.html）和[fetchMode]（https://grails.github.io/ grails-doc/3.0.x/guide/GORM.html） – dmahapatro
我之前做過，沒有改變，但我認爲我發現了這個問題。 我會爲這篇文章添加一個答案，並將在github上打開一張票。 感謝您的時間！ –