There was talk of adding a constraint feature to SVG 1.2 but it wasn't adopted, so you need to code constraints procedurally.

存在向 SVG 1.2 添加约束特性的观点，但是没有被采纳，所以您需要以程序的方式编写约束。

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This can take the form of adding a column, changing the data type for a column, adding a constraint, or even deleting a column.

这可以采用添加列、更改列的数据类型、添加约束或者甚至删除列的方式来实现。

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