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UserType for SQLData Types

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beelzebot

Post subject: UserType for SQLData Types

Posted: Wed Sep 22, 2004 5:04 pm

Newbie

Joined: Wed Sep 22, 2004 10:10 am
Posts: 15
Location: Darmstadt, Germany

Hibernate version:
2.1.6

Name and version of the database you are using:
Oracle 9i, JDBC Driver: classes12.zip

Hello everyone,

we have an Oracle 9i (9.2) DB which uses some UDTs, like the following:

Code:

create or replace type color as object (r number, g number,b number);

These are part of existing classes. Until now, these have been accessed using the SQLData interface. From searching through the Forum, I found several pointers to the UserType/CompositeUserType Interfaces, and tried to implement these. However, even after looking through the Reference, Hibernate in Action Chapter 6.1 and the APIdoc, I do not understand how to implement the two methods nullSafeGet() and nullsafeSet() in my case. Could anyone give me a hint what I have do do in these with my UDT?

The portion of the mapping file for the table thast has this color UDT looks like this:

Code:

    <property
        name="color"
        type="net.sf.hibernate.type.Color"
        column="COLOR">

        <meta attribute="field-description">
           @hibernate.property
            column="COLOR"
        </meta>    
    </property> 

Unfortunately, I keep getting Exceptions when trying to instantiate a Session., so I assume there is a mistake in the UserType, and more specific, in my implementations of the aforementioned methods.

I am not very happy with these UDTs, however, changing the DB schema is, very unfortunately, not an option, since several legacy apps use it.

Thanks in Advance & regards,

Thorsten

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michael

Post subject:

Posted: Wed Sep 22, 2004 5:54 pm

Hibernate Team

Joined: Tue Sep 09, 2003 2:10 pm
Posts: 3246
Location: Passau, Germany

Just look at some other already existing UserTypes - there are various in the Wiki Area on the website, in the Hibernate Unit Tests, etc.

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beelzebot

Post subject:

Posted: Thu Sep 23, 2004 11:18 am

Newbie

Joined: Wed Sep 22, 2004 10:10 am
Posts: 15
Location: Darmstadt, Germany

Thanks for the quick reply!

OK, I had a look at the various UserTypes that have been placed in the WIKI, and according to the patterns in these, I wrote ("sketched") these methods:

Code:

public Object nullSafeGet(ResultSet resultSet, String[] names,
                              java.lang.Object owner) throws HibernateException,
        SQLException {

        if (resultSet.wasNull()) { return null; }
        else {
            Color color = new Color();
            SQLInput stream = (SQLInput) resultSet.getBinaryStream("COLOR");
            color.r = stream.readDouble();
            color.g = stream.readDouble();
            color.b = stream.readDouble();
            return color;
        }
}

and

Code:

public void nullSafeSet(PreparedStatement statement, Object value,
                            int index) throws
        HibernateException, SQLException {

        if (value == null) {
            statement.setNull(index, 0);
        }
        else {
            Color color = (Color) value;
            SQLOutput stream;
            stream.writeDouble(color.r);
            stream.writeDouble(color.g);
            stream.writeDouble(color.b);

            statement.setBinaryStream(index, (InputStream) stream, 128);
        }
}

Is this, in principle, the right pattern? (I know what I am doing above dosn't actually work, as I have not yet found a way to get a SQLInput from a ResultSet and/or a SQLOutput from a PreparedStatement - but I assume there is some way.).

Thanks again & best regards,

Thorsten

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michael

Post subject:

Posted: Thu Sep 23, 2004 3:05 pm

Hibernate Team

Joined: Tue Sep 09, 2003 2:10 pm
Posts: 3246
Location: Passau, Germany

Looks alright to me

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