Criteria查询中的数学运算符 [英] Math operators in Criteria queries
问题描述
@Entity
public class MyTestClass {
/ * id和东西* /
私人整数aValue;
私人整数b值;
}
您可以使用HQL执行以下操作:
查询查询
= getCurrentSession()。createQuery(从MyTestClass中选择aValue * bValue);
列表< Double> resultList = query.list;
并计算结果。
是否有可能使用Criteria API做类似于此的事情?我仍然没有找到使用Criteria API使用数学运算的方法。我们有总和函数,如sum,avg等,但不是基本的数学运算符?解析方案
您可以创建一个新的属性在你的班级,这是计算的价值。只需指定该属性的公式属性即可。然后你可以在你的标准中包含这个属性。
< property name =productformula =aValue * bValue/ >公式(可选):一个SQL表达式,用于定义计算属性的值。
计算属性没有自己的列映射。
Given the mapped hibernate class:
@Entity
public class MyTestClass {
/* id and stuff */
private Integer aValue;
private Integer bValue;
}
you can do the following with HQL:
Query query
= getCurrentSession().createQuery("select aValue * bValue from MyTestClass");
List<Double> resultList = query.list;
and get the calculated result out.
Is it possible to do something similar to this with the Criteria API? I still haven't found a way to use math operations with the Criteria API. We have aggregate functions like sum, avg and so on, but not the basic math operators?
You can make a new property in your class that is this computed value. Just specify the formula attribute for that property. Then you can include this property in your Criteria.
<property name="product" formula="aValue*bValue" />
formula (optional): an SQL expression that defines the value for a computed property. Computed properties do not have a column mapping of their own.
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