java 无法执行 JDBC 批量更新
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Could not execute JDBC batch update
提问by lassejl
i have a little trouble while making my first play application.
我在制作第一个播放应用程序时遇到了一些麻烦。
I got a class Meal which can have one or more MealEntries in it. One meal entry can be used by several meals (i.e if u eat 2 eggs for more than one meal). But im getting a exception.
我有一个类 Meal，其中可以包含一个或多个 MealEntries。一餐条目可用于多餐（即，如果您在多餐中吃 2 个鸡蛋）。但我有一个例外。
I can understand why i get the exception, but i cant figure how i can cure it.
我可以理解为什么会出现异常，但我无法弄清楚如何治愈它。
This is my exception:
这是我的例外：
Caused by: java.sql.BatchUpdateException: Duplicate entry '4' for key 'mealEntries_id'
at com.mysql.jdbc.PreparedStatement.executeBatchSerially(PreparedStatement.java:2020)
at com.mysql.jdbc.PreparedStatement.executeBatch(PreparedStatement.java:1451)
at com.mchange.v2.c3p0.impl.NewProxyPreparedStatement.executeBatch(NewProxyPreparedStatement.java:1723)
at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:70)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:268)
... 12 more
Meal Class:
膳食类：
public class Meal extends Model {
public String name;
public Date consumed;
@OneToMany
public List<MealEntry> mealEntries;
}
MealEntry Class:
膳食入门类：
public class MealEntry extends Model {
public int amount;
@OneToOne
public Unit unit;
@OneToOne
public FoodType type;
@OneToOne
public MealEntry with;
}
Thanks in advance
提前致谢
Edit:Tried to create a testcase, but ran into some other error. I'll try to explain: The exception happens when i try to create a second meal, using MealEntries that are also used by the first Meal.
编辑：试图创建一个测试用例，但遇到了其他一些错误。我将尝试解释：当我尝试使用第一餐也使用的 MealEntries 创建第二餐时，会发生异常。
采纳答案by lassejl
Thanks for the feedback, but i figured it out.
感谢您的反馈，但我想通了。
I changed my Meal to MealEntry relation to @ManyToMany and it solved the problem.
我将 Meal 更改为 MealEntry 与 @ManyToMany 的关系，它解决了问题。
回答by jzd
Looks like you have a database constraint that does not allow you to insert these duplicates. Update your database structure or find a way to represent the meal in the current structure.
看起来您有一个数据库约束，不允许您插入这些重复项。更新您的数据库结构或找到一种方法来表示当前结构中的膳食。
回答by mandubian
Give us a bit more information because without the requests you perform, it's not really easy to see why you have duplicates...
给我们更多信息，因为如果没有您执行的请求，就很难看出为什么会有重复...
