Question

我有一流网,用户可以更新数据库中的表格。我想知道这样做的适当方法。如你在以下图像中看到的那样,红沙区是我通常掌握的数据,即:我需要更新<>>>>not。

enter image description here

Here are the steps that I need to take:

Don t update data if it exists
Delete data that is not in the user update
Add data from the user update that is not already in the table

我也需要审计这一表格,因此我将对此有所启发。我想从理论上知道,在表格上进行这种更新的最佳方式是什么?

thank you to Aaron who introduced the concept of merge.

下表数据显示:

foreignkey  model  primarykey
1            AA       1
1            AA1      2
1            AA3      3
23           B        4
22           C        5

用户将增加这方面的数据:

foreignkey  model  primarykey
1            A1       1
1            AA1      2
1            AA3      3
22           C        5

如你所知,第一行已经更新,第二行至最后一行完全删除。您能否帮助我再次发言?

Answer 1

是的,它有可能,它被称为一种合并。见“服务器”文件。 MERGE 声明。

If you don t want to perform any updates if the data already exists, then just don t add a WHEN MATCHED clause. USE WHEN NOT MATCHED BY SOURCE and WHEN NOT MATCHED BY TARGET to insert/delete the missing/removed rows.

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