使用Java和Hibernate HQL进行帐户余额验证

Question

我当前的“帐户余额”对象中具有以下属性：

long id;                     // Database ID
Date date;                   // date when this balance object was created
boolean currentBalanceFlag;  // indicates this is the most recent balance
float amount;                // the total sum currently in the account balance
float depositAmount;         // amount deposited that resulted in this objects amount 
float withdrawalAmount;      // amount withdrawn that resulted in this objects amount
Balance lastBalance;         // last balance object for traversing
User user;                   // owner of the balance
String note;                 // detailed description of transaction that resulted in current blanace

天平仅执行两个操作。 存款和取款。

问题是：

如何创建HQL查询，该查询将：

-将所有user的depositAmount
-求和所有user withdrawalAmount金额
-从第二求和中减去第一求和的结果
-将减法结果与currentBalanceFlag等于true Balance对象中的user amount进行比较

用伪代码：

resultAmount = select ( sum(depositAmount) - sum(withdrawalAmount) ) from Balance where user=user
amount = select amount from Balance where user=user and currentBalanceFlag=true

我想通过HQL查询从单次调用数据库获得最终的布尔结果：

resultAmount == amount

Answer 1

select (sum(flow.depositAmount) - sum(flow.withdrawalAmount) - current.amount) 
from Balance flow, Balance current
where flow.user=:user
and current.user=:user 
and current.currentBalanceFlag=true

这将返回所有流量的总和与当前余额之间的差。

附带说明，您不必检查数据的完整性。 除非您有成千上万的行，否则用SQL和计算当前余额应该足够快。