[英]GAE/J datastore : how to build an IN query with JDO
我正在尝试通过Google App Engine数据存储区中的键查询实体集合。 这是我尝试执行的查询,但没有成功:
Query query = pm.newQuery(Fix.class);
query.setFilter("__key__ IN param");
query.declareParameters("com.google.appengine.api.datastore.Key param");
query.execute(list); // list is an array of keys
我得到的错误是:
javax.jdo.JDOUserException: Portion of expression could not be parsed: IN param
是否可以通过JDO或通过密钥查找实体的低级API使用构建IN查询?
我想你可能会混淆了JDO和JPA语法:见例子此页
JPA:
select from Person where
favoriteFood IN ('cheeseburger', 'pizza', 'fried chicken')
order by favoriteFood, age
JDO:
Query q = pm.newQuery(
"select from Person where :p1.contains(favoriteFood) order by favoriteFood, age");
q.execute(Arrays.asList("cheeseburger", "pizza", "fried chicken"));
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