how to save an object with 'foreign object'

问题:

This is my database:

CREATE TABLE other (
    id integer primary key autoincrement not null,
    texto text
);

CREATE TABLE tabela (campoid INTEGER primary key autoincrement not null, 
                        camponome text not null, chave int,
                        foreign key (chave) references other(id));

and this is my classes:

@DatabaseTable(tableName = "tabela")
public class Bean {

    @DatabaseField(columnName = "campoid", generatedId = true)
    private int _id;

    @DatabaseField(columnName = "camponome")
    private String nome;

    @DatabaseField(foreign = true, columnName = "chave", canBeNull = false)
    private Part chave;
}

and other classe mapped

@DatabaseTable(tableName = "other")
public class Part {

    @DatabaseField(generatedId = true, columnName = "id")
    private Integer id;

    @DatabaseField(columnName = "texto")
    private String texto;
}

but when i save an Bean object, the Object 'part' does not save too :(

        Helper helper = OpenHelperManager.getHelper(this, Helper.class);
        Dao<Bean, Integer> dao = helper.getDao(Bean.class);

        Bean firstBean = new Bean();
        firstBean.setNome("first be persisted");

        Part part = new Part();
        part.setTexto("ANY TEXT");
        firstBean.setChave(part);

        dao.create(firstBean);

in my log:

07-13 00:25:26.602: D/BaseMappedStatement(3796): insert data with statement 'INSERT INTO tabela (camponome ,chave ) VALUES (?,?)' and 2 args, changed 1 rows

any idea?

回答1:

but when i save an Bean object, the Object 'part' does not save too :(

Right. ORMLite does not by default persist sub-objects when you create an object. You can turn on the foreignAutoCreate = true flag which will do that for you however. See the javadocs for foreignAutoCreate.

Your chave field should be defined then as:

@DatabaseField(foreign = true, columnName = "chave", canBeNull = false,
    foreignAutoCreate = true)
private Part chave;

If you want to do it by hand, you should:

partDao.create(firstBean.chave);
beanDao.create(firstBean);

You create the Part in the database first because you need the ID from the Part which will be saved into your bean.