删除1年多以前的记录 [英] Delete records from more than 1 year ago

问题描述

我正在使用spring JPA Repositories在我的数据库中保存Twitter推文。推文的日期在MySQL数据库中保存为日期时间。现在我要删除所有超过一年的推文。我看到有函数 CURRENT_TIME ，我想到的是像 CURRENT_TIME - 360 。我知道这不是正确的语法，但我不知道如何做到这一点。以下是我所拥有的：

I'm saving twitter tweets in my database with spring JPA Repositories. The date of the tweet is saved as Datetime in the MySQL db. Now I want to delete all tweets that are older than one year. I saw there is the function CURRENT_TIME and I thought of something like CURRENT_TIME - 360. I know thats not the correct syntax but I have no idea how to do this. Here is what I have:

@Modifying
@Transactional
@Query("DELETE FROM Tweetpost t WHERE t.createdAt > ")
int removeOlderThan();

编辑已解决：

存储库：

@Modifying
    @Transactional
    @Query("DELETE FROM Tweetpost m WHERE m.createdAt < :date")
    int removeOlderThan(@Param("date") java.sql.Date date);

服务：

public void removeOldItems() {
        Calendar cal = Calendar.getInstance();
        cal.add(Calendar.DATE, -360);

        java.sql.Date oneYear = new java.sql.Date(cal.getTimeInMillis());

        tweetRepository.removeOlderThan(oneYear);


    }

推荐答案

为此您需要2个步骤。首先，你需要一个方法，将你想要删除消息的日期作为参数，你根本不需要 @Query 注释。

For this you need 2 steps. First of all you need a method that will take as a parameter the date of which you want to delete the messages and you dont need tha @Query annotation at all.

因此，在您的存储库中，您必须拥有类似

So in your repository you must have something like

    @Modifying
    public void deleteByCreatedAtBefore(Date expiryDate);

现在，在您的服务方法中，您将计算日期并像这样传递

Now in your service method, you will calculate the Date and pass it on like this

    public void performTweetCleanup(){
       //calculate date
       Calendar cal = Calendar.getInstance();
       Date today = cal.getTime();
       cal.add(Calendar.YEAR, -1);
       Date previousYear = cal.getTime();

       //call the method
       MyTweeterRepository.deleteByCreatedAtBefore(previousYear);
     }

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