Multiple ForeignCollection of same type in ORMLite

Question

I'm using OrmLite on android for a structure simmilar to the following :

The Book class has a collection of primary BookArticle and a collection of secondary BookArticle :

    @DatabaseTable(tableName = "BookV1", daoClass = BookDaoImplV1.class)
public class Book implements IBook {

    @DatabaseField(id = true)
    private String id;

    @ForeignCollectionField(eager = false)
    private ForeignCollection<BookArticle> primaryArticles;

    @ForeignCollectionField(eager = false)
    private ForeignCollection<BookArticle> secondaryArticles;

    // constructor getters setters etc...

}

Then the BookArticle is declared as follow :

    @DatabaseTable(tableName = "BookArticleV1", daoClass = BookArticleDaoImplV1.class)
public class BookArticle implements IBookArticle {

    @DatabaseField(id = true)
    private String id;

    @DatabaseField
    private String title;

    @DatabaseField
    private String summary;

    // for ORM mapping only
    @DatabaseField(foreign = true, foreignAutoRefresh = true, columnName = BOOK_FIELDNAME, index = true)
    private Book book;

    // constructor getters setters etc..

}

now saving the BookArticles and Book with DAO works fine however when I want to fetch my Book entity from database and access either primary or secondary articles (after a refresh() ) I have a problem because both collections hold ALL the articles (both primary and secondary) that have the book's id in their 'book' column.

Obviously I would need these primary and secondary articles to be separated when fetched from DB.

I would have expected "foreignFieldName" to be the answer to my problem.

@ForeignCollectionField(eager = false, foreignFieldName = "secondaryArticles")
private ForeignCollection<BookArticle> secondaryArticles;

but apparently it does not work that way.

Is there a way for me to differenciate between these two collections ? Maybe using a simple annotation argument such as "owningFieldName" or similar that would get persisted in DB alongside the BookArticle data?

Many thanks for your help.

Alex

Answer 1

I ran into the same problem.

Not a real solution but you can try to use only one list with a boolean for switching between primary/secondary articles like this:

@DatabaseTable(tableName = "BookV1", daoClass = BookDaoImplV1.class)
public class Book implements IBook {

    @DatabaseField(id = true)
    private String id;

    @ForeignCollectionField(eager = false)
    private ForeignCollection<BookArticle> articles;

    // constructor getters setters etc...

}

And then for the BookArticle class

@DatabaseTable(tableName = "BookArticleV1", daoClass = BookArticleDaoImplV1.class)
public class BookArticle implements IBookArticle {

    @DatabaseField(id = true)
    private String id;

    @DatabaseField
    private String title;

    @DatabaseField
    private String summary;

    @DatabaseField
    private boolean isSecondary;

    // for ORM mapping only
    @DatabaseField(foreign = true, foreignAutoRefresh = true, columnName = BOOK_FIELDNAME, index = true)
    private Book book;

    // constructor getters setters etc..

}

Hoping to see a real answer

Answer 2

if you want to add multible ForeignerCollections form the same typ to one class, you have to add 2 fields for ORM-Mapping in the BookArticle class and link this in the Book class to the ORM-Mapping fields.

e.g

Book class

@ForeignCollectionField(eager = false, foreignFieldName = "primaryBook")
private ForeignCollection<BookArticle> primaryArticles;

@ForeignCollectionField(eager = false, foreignFieldName = "secondaryBook")
private ForeignCollection<BookArticle> secondaryArticles;

BookArticle class

// for ORM mapping primary Books
@DatabaseField(foreign = true, foreignAutoRefresh = true, columnName = BOOK_FIELDNAME, index = true)
private Book primaryBook;

// for ORM mapping secondary Books
@DatabaseField(foreign = true, foreignAutoRefresh = true, columnName = BOOK_FIELDNAME, index = true)
private Book secondaryBook;

When you call now bookDao.queryAll() and access the secondary Articles list, you will see the articles are correctly linked.

The disadvantage is, that you have 2 columes in the BookArticle Table for foreigner keys.

Greeting, Codenix