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.execute         


        

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')

Answer 2

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/.

Answer 3

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')