英文:
How do I make sure that I insert SQL data in right order with Spring JPA?
问题
当我插入：
data1
data2
data3
data4
data5
..
..
..
dataN
使用以下代码将数据插入到MySQL数据库：
DataLogg dataLogg = new DataLogg(0, time, DO0, DO1, DO2, DO3, AI0, AI1, AI2, AI3, loggerIdValue, samplingTimeValue, pulseNumber, ControlView.selectedBreakPulseLimit, stopSignal, comment);
dataLoggRepository.saveAndFlush(dataLogg);
如果运气不好的话，数据插入的顺序可能是这样的：
data1
data2
data4
data3
dataN
..
..
..
data5
问题：
我如何保证插入行的顺序与读取行的顺序相同？我不希望数据以随机顺序显示。最新的数据需要在顶部，最旧的数据需要在底部。
英文:
When I insert:
data1
data2
data3
data4
data5
..
..
..
dataN
Into a MySQL database with this code:
DataLogg dataLogg = new DataLogg(0, time, DO0, DO1, DO2, DO3, AI0, AI1, AI2, AI3, loggerIdValue, samplingTimeValue, pulseNumber, ControlView.selectedBreakPulseLimit, stopSignal, comment);
dataLoggRepository.saveAndFlush(dataLogg);
It will insert data like this, if I have bad luck.
data1
data2
data4
data3
dataN
..
..
..
data5
Question:
How can I guarantee that the same order I insert the rows, I can read them as the same order as well? I don't want it in random order. The last data need to be at the top and the first data need to be at the bottom.
答案1
得分: 3
你问：
> 我怎样才能确保我插入行的顺序，我在读取它们时也能保持相同的顺序？
答案是，在 SQL 表中实际上没有内部的“顺序”。当查询时确保特定顺序的方式是在查询中使用 ORDER BY 子句，例如：
SELECT name
FROM yourTable
ORDER BY name;
英文:
You asked:
> How can I guarantee that the same order I insert the rows, I can read them as the same order as well?
The answer is that there is no internal "order" to a SQL table, for all intents and purposes. The way you ensure a certain order when querying is to use an ORDER BY clause with the query, e.g.
SELECT name
FROM yourTable
ORDER BY name;
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