使用ORMLite for
Android,我需要构建一个按订单ID或客户名称返回订单的查询.请考虑以下类声明：
@DatabaseTable(tableName = "order")
public class Order {
@DatabaseField(generatedId = true)
private Long id;
@DatabaseField(foreign = true,canBeNull = false,foreignAutoRefresh = true,columnName = "customer_id")
private Customer customer;
// default constructor,getters and setters...
}
@DatabaseTable(tableName = "customer")
public class Customer {
@DatabaseField(generatedId = true)
private Long id;
@DatabaseField
private String name;
// default constructor,getters and setters...
}
我正在寻找的原始sql将是这样的：
SELECT
o.*
FROM
order o
JOIN customer c on
o.customer_id = c.id
WHERE
(o.id = ?) OR (c.name = ?)
使用ORMLite执行此操作的最佳方法是什么？
解决方法
ORMLite现在支持
simple join queries.
所以你的查询看起来像这样：
QueryBuilder<Customer,Integer> customerQb = customerDao.queryBuilder();
SelectArg nameSelectArg = new SelectArg();
// this gives the c.name = ?
customerQb.where().eq("name",nameSelectArg);
QueryBuilder<Account,Integer> orderQb = orderDao.queryBuilder();
SelectArg idSelectArg = new SelectArg();
// this gives the o.id = ?
orderQb.where().eq("id",idSelectArg);
orderQb.join(customerQb);
// then you set the args and run the query
nameSelectArg.setValue("jim");
idSelectArg.setValue(1);
List<Order> results = orderQb.join(customerQb).query();
