On Mar 4, 2008, at 3:39 PM, Werner Guttmann wrote:
Brett,
the sql mapping for the authors field of the class Book should read:
<sql name="author_id"
many-table="dw_books_authors"
many-key="book_isbn" />
Ok, I got this working, but troubles continue. Here's my complete sql-
mapping.xml:
<mapping>
<class name="ibm.xml.castor.Book" identity="isbn">
<map-to table="dw_books"/>
<field name="isbn" type="string">
<sql name="isbn" type="varchar" />
</field>
<field name="title" type="string">
<sql name="title" type="varchar" />
</field>
<field name="authors" type="ibm.xml.castor.Author"
collection="arraylist" required="true">
<sql name="author_id"
many-table="dw_books_authors"
many-key="book_isbn" />
</field>
</class>
<class name="ibm.xml.castor.Author" identity="id">
<map-to table="dw_authors" />
<field name="id" type="int">
<sql name="id" type="integer" />
</field>
<field name="firstName" type="string">
<sql name="first_name" type="varchar" />
</field>
<field name="lastName" type="string">
<sql name="last_name" type="varchar" />
</field>
<field name="books" type="ibm.xml.castor.Book"
collection="arraylist" required="true">
<sql name="book_isbn"
many-table="dw_books_authors"
many-key="author_id" />
</field>
</class>
</mapping>
Here's my test program:
public class SQLTester {
public static void main(String args[]) {
try {
JDOManager.loadConfiguration("jdo-conf.xml");
JDOManager jdoManager = JDOManager.createInstance("bmclaugh");
Database database = jdoManager.getDatabase();
database.begin();
Author author = new Author(1001, "Joseph", "Conrad");
Book book = new Book("1892295490", "Heart of Darkness", author);
database.create(book);
// database.create(author);
Book lookup = (Book)database.load(Book.class, "1892295490");
System.out.println("Located book is named " + lookup.getTitle());
System.out.println("Authors:");
for (Iterator i = lookup.getAuthors().iterator(); i.hasNext
(); ) {
Author bookAuthor = (Author)i.next();
System.out.println(" " + bookAuthor.getFirstName() + " " +
bookAuthor.getLastName());
}
// database.remove(lookup);
database.commit();
database.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
There are several things I'm seeing that don't make sense to me:
1. No entry is ever inserted into dw_books_authors. I don't
understand why the mapping isn't taking care of this. When I do
database.create(book), isn't that enough to trigger Castor persisting
the book, the author, and the relationship between them?
Additionally, I get no entries in the authors table.
2. Even if I add in the database.create(author) line -- which I don't
think I should need -- this still doesn't work. In that case, an
author is inserted into the authors table, but there's still nothing
in dw_books_authors.
3. Despite no entries in the dw_authors or dw_books_authors, when I
pull the lookup Book from the database, it DOES have a populated
Author object with the right author name. I can't see how there's
nothing in dw_authors or dw_book_authors, yet lookup can have a
correct author entry.
Any ideas? I'm really pulling my hair out over this; I finally got
the underscore thing corrected, and am running into some more
trouble. I welcome any help, or any questions that I can answer to
help you help me :-)
Thanks
---
Brett McLaughlin
Series Editor, Head First
O'Reilly Media, Inc.
Phone: (972) 722-6252
Fax: (972) 692-7958
E-Mail: [EMAIL PROTECTED]
