分页以进行更新.是否有可能? [英] Pagination for update. Is it possible?

问题描述

它们是否存在一些处理分页以进行更新的方法? 例如，我有100行类型:

Are they exist some methods to handle pagination for update? For example i have 100 rows of type:

@Id
private Integer id;
@Column
private boolean flag;
@Column
private Date last;

开始时，它们看起来像:id，false，null

In start they looks like: id, false, null

我有持久性方法:

@Query("SELECT t FROM Test t WHERE (t.last < :processStart OR t.last IS NULL)")
Page<Test> find(Pageable pageable, @Param("processStart") Date processStart);

我需要10个，分别设置标志true和last = new Date()并将其保存回数据库.

I need take 10, set flag true and last = new Date() for each and save it back to DB.

实施方式如下:

Date start = new Date();
for (int i = 0; i < 10; i++) {
    Pageable request = new PageRequest(i, 10, SortDirectuin.ASC, "id");
    Page page = testPersistence.find(request, start);
    page.getContext().forEach(t -> {
        ..huge part of another operation..
        t.setFlag(true);
        t.setLast(new Date());
        testPersistence.save(t);
    });
}

首页上下文的ID应为:0..9; 第二:10..19;

First page context should be with id: 0..9; Second: 10..19;

但是在我的情况下，第二页返回的ID为:20..29;

But in my case second page returns with id: 20..29;

在分页结束时，我丢失了一半的数据. 返回:0..9、20..29、40..49，等等.

And in end of pagination i lost half of data. Returns: 0..9, 20..29, 40..49, etc.

如何防止这种情况?

推荐答案

我发明了一种自行车方法，并尝试对其进行解释:

I invented one bicycle method, and I try to explain it:

分页的工作方式如下:

1) row1 |        2) row1
   row2 | get1      row2
   row3 |           row3
   row4             row4 |
   row5             row5 | get2
   row6             row6 |
   row7             row7
   row8             row8
   row9             row9

但是在我的情况下，我的行已更改，并且它们不符合请求.所以分页看起来像:

But in my case my rows are changed and they do not comply with the request. So pagination looks like:

1) row1 |        2) row4
   row2 | get1      row5
   row3 |           row6
   row4             row7 |
   row5             row8 | get2
   row6             row9 |
   row7             
   row8             
   row9             

糟糕，我失去了一套分页周期.

Oops, i lose one pagination cycle set.

我的解决方案不是增量页面.并始终获得首页，外观如下:

My solution is not increment page. And get first page all time It will be looks like:

1) row1 |        2) row4 |       3) row7 |
   row2 | get1      row5 | get1     row8 | get1
   row3 |           row6 |          row9 |
   row4             row7
   row5             row8
   row6             row9
   row7             
   row8             
   row9            

在这种情况下，我不会丢失任何行. 但是我再说一遍，这是自行车解决方案，在另一种情况下可能不起作用.

In this case i don't lose any rows. But i repeat, it is so bicycle solution and it maybe does not work in another case.

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