How to use native sql function with HQL query?

问题:

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?

回答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')

回答2:

Well i achieved this by adding custom functions like this in an Overwritten dialect.

class MySqlDialect extends MySQL5InnoDBDialect {

    public MySqlDialect() {
        super();
        registerFunction("date_add_interval", new SQLFunctionTemplate(StandardBasicTypes.DATE, "date_add(?1, INTERVAL ?2 ?3)"));
        registerFunction("date_sub_interval", new SQLFunctionTemplate(StandardBasicTypes.DATE, "date_sub(?1, INTERVAL ?2 ?3)"));
        registerFunction("to_date", new SQLFunctionTemplate(StandardBasicTypes.DATE, "str_to_date(?1, ?2)"));
        registerFunction("minutes_diff", new SQLFunctionTemplate(StandardBasicTypes.LONG, "timestampdiff(MINUTE, ?1, ?2)"));
    }

    public String openBlobSelectQuote() {
        return "`";
    }

    public String closeBlobSelectQuote() {
        return "`";
    }
}

Update : Function Registration:

    registerFunction("getlength", new SQLFunctionTemplate(StandardBasicTypes.LONG, "dbms_lob.getlength(?1)"));

Your HQL Query:

def results = Attachment.executeQuery(
    'select id, originalFilename, 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')

回答3:

You can always use basic java jdbc connection in order to execute query. Create the java code for this and store it in src/java/.