如何限制mysql表中可以存储的行数? [英] How to limit number of rows can be store in mysql table?

问题描述

我需要将MySQL表中可以插入的行数限制为，仅10条.我只需要从MySQL实现此功能，即无需使用任何编程语言即可.

I need to limit the number of rows can be insert in a MySQL Table to 10 only. I need to implement this from MySQL only i.e without using any programming language.

我已经创建了一个实现 MAX_ROWS = 10 的表，但是它不起作用.

I have created a table with implementing MAX_ROWS = 10 but its not working.

请检查这些屏幕截图.

我很困惑该怎么做.如果有人会为我提供解决方案，那对我真的很有帮助.

I'm very confused how to do this. If someone will provide me the solution, that would be really helpful for me.

谢谢.

推荐答案

我认为MySQL没有提供这种内置功能.一种解决方案是您可以创建触发器.

I think there is no such inbuilt functionality providede by MySQL. One solution is that you can create trigger.

CREATE TRIGGER your_trigger_name
BEFORE INSERT ON your_table_name
FOR EACH ROW
BEGIN
    DECLARE cnt INT;

    SELECT count(*) INTO cnt FROM your_table_name;

    IF cnt = 10 THEN
        SIGNAL SQLSTATE '45000' SET MESSAGE_TEXT = 'You can store only 10 records.';
    END IF;
END;

在桌上尝试上面的触发器.将您的表名替换为您的表名.

Try above trigger on your table. Replace your table_name with your_table_name.

希望这会对您有所帮助.

Hope this will help you.

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