Question

I have just started to read about ORMLite so I am still a beginner.
As far as I understand I can query objects using any of their persistent attributes.

For example, if I have the following classes:

@DatabaseTable
public class Bill {
  @DatabaseField String code;
  Client client; 
  List<Item> items;
}

@DatabaseTable
class Client {
  @DatabaseField String name;
}

@DatabaseTable
class Item {
  @DatabaseField String name;
}

(not sure how to annotate the client and items attributes in the class Bill).

In any case, a query like this will help me to obtain all the Bill objects with a particular code number:

QueryBuilder<Bill, String> queryBuilder = BillDao.queryBuilder();
Where<Bill, String> where = queryBuilder.where();
where.eq(BILL.NAME_CODE, "abc123");
PreparedQuery<Account> preparedQuery = queryBuilder.prepare();

My question is: what is the recommended way in ORMLite to write queries that have conditions in transitive relations of my model object ? for example “All the bills that include a particular item with a certain name”? or “All the clients that have bought an item with a certain name” ?.

Thanks in advance!.

Answer 1

Read Foreign Object Fields and Foreign Collections in ormLite docs.

Your relationship will be:

@DatabaseTable(tableName = "bills")
public class Bill {
    public static final String ACCOUNT_ID_FIELD_NAME = "client_id";
    @DatabaseField(generatedId = true)
    private int id;
    @DatabaseField(foreign = true, columnName = ACCOUNT_ID_FIELD_NAME)
    private Client client;
    @DatabaseField 
    private String code;
    Client client; 
    List<Item> items;

    public Bill(){

    }
    public Bill(Client client, String code){
        this.client = client;
        this.code = code;
    }

    public int getId(){
        return this.id;
    }
    public String getCode(){
        return this.code;
    }
}

@DatabaseTable(tableName = "clients")
class Client {
    public static final String NAME_FIELD_NAME = "name";
    public Client() {
        // all persisted classes must define a no-arg constructor with at least package visibility
    }
    public Client(String name) {
        this.name = name;
    }
    @DatabaseField(generatedId = true)
    private int id;
    @DatabaseField(columnName = NAME_FIELD_NAME, canBeNull = false) 
    private String name;

    public int getId(){
        return this.id;
    }
    public String getName(){
        return this.name;
    }
}

More information can be found in the code examples.