How to use native sql function with HQL query?

Question

I am trying to execute a query like the following, using HQL, that uses a native SQL function (dbms_lob.getlength):

def results = Attachment.executeQuery(
    'select id, originalFilename, dbms_lob.getlength(a.fileBytes), dateCreated, createUserName '+
    'from Attachment a where a.id not in '+
         '(select attachmentId from SpecVersion sv where sv.attachmentId is not null) '+
    'and a.dateCreated > sysdate - 30')

• The fileBytes column is a BLOB - I am trying to get the size of the BLOB content.

However, this results in the error below.

java.lang.IllegalStateException: No data type for node: org.hibernate.hql.ast.tree.MethodNode
 +-[METHOD_CALL] MethodNode: '('
 |  +-[METHOD_NAME] IdentNode: 'dbms_lob.getlength' {originalText=dbms_lob.getlength}
 |  \-[EXPR_LIST] SqlNode: 'exprList'
 |     \-[DOT] DotNode: 'attachment0_.file_bytes' {propertyName=fileBytes,dereferenceType=ALL,propertyPath=fileBytes,path=a.fileBytes,tableAlias=attachment0_,className=com.et.layoutmgr.grails.mapping.Attachment,classAlias=a}
 |        +-[ALIAS_REF] IdentNode: 'attachment0_.ATTACHMENT_ID' {alias=a, className=com.et.layoutmgr.grails.mapping.Attachment, tableAlias=attachment0_}
 |        \-[IDENT] IdentNode: 'fileBytes' {originalText=fileBytes}

        at org.hibernate.hql.ast.tree.SelectClause.initializeExplicitSelectClause(SelectClause.java:156)
        at org.hibernate.hql.ast.HqlSqlWalker.useSelectClause(HqlSqlWalker.java:857)
        at org.hibernate.hql.ast.HqlSqlWalker.processQuery(HqlSqlWalker.java:645)
        at org.hibernate.hql.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:685)
        at org.hibernate.hql.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:301)
        at org.hibernate.hql.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:244)
        at org.hibernate.hql.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:256)
        at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:187)
        at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:138)
        at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:101)
        at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:80)
        at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:124)
        at org.hibernate.impl.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:156)
        at org.hibernate.impl.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:135)
        at org.hibernate.impl.SessionImpl.createQuery(SessionImpl.java:1770)
        at org.codehaus.groovy.grails.orm.hibernate.metaclass.ExecuteQueryPersistentMethod$2.doInHibernate(ExecuteQueryPersistentMethod.java:81)
        at org.springframework.orm.hibernate3.HibernateTemplate.doExecute(HibernateTemplate.java:406)
        at org.springframework.orm.hibernate3.HibernateTemplate.executeFind(HibernateTemplate.java:343)
        at org.codehaus.groovy.grails.orm.hibernate.metaclass.ExecuteQueryPersistentMethod.doInvokeInternal(ExecuteQueryPersistentMethod.java:79)
        at org.codehaus.groovy.grails.orm.hibernate.metaclass.AbstractStaticPersistentMethod.invoke(AbstractStaticPersistentMethod.java:72)
        at org.codehaus.groovy.grails.orm.hibernate.metaclass.AbstractStaticPersistentMethod.invoke(AbstractStaticPersistentMethod.java:65)

Is something like this possible using HQL, or do I need to switch to using native SQL?

Answer 1

In Attachment domain add new field Long fileBytesLength and inside mapping closure add the formula for calculating the length of fileBytes field.

class Attachment {

    String createUserName
    String originalFilename

    byte[] fileBytes
    Long fileBytesLength

    Date dateCreated
    //Other Properties

    static mapping = {
        //Other mappings
        fileLength formula: "dbms_lob.getlength(fileBytes)"
    }
}

And then modify the query to:

def results = Attachment.executeQuery(
    'select id, originalFilename, fileBytesLength, dateCreated, createUserName '+
    'from Attachment a where a.id not in '+
         '(select attachmentId from SpecVersion sv where sv.attachmentId is not null) '+
    'and a.dateCreated > sysdate - 30')