rails "column "traffic_total" cannot be cast automatically "报错解决方案

其他 2019-01-25 21:41:20 阅读次数: 0

有时，rails修改字段类型的时候，会报一个不能转换的错误，比如varchar转float

错误代码如下：

PG::DatatypeMismatch: ERROR:  column "traffic_total" cannot be cast automatically to type double
HINT:  Specify a USING expression to perform the conversion.

这个时候有两种解决办法：

1.推荐做法

def change
    change_column :sim_cards, :traffic_total, 'double precision USING CAST(traffic_total AS double precision)'
end

2.删除字段，再添加

def change
    remove_column :sim_cards, :traffic_total
    add_column :sim_cards, :traffic_total, :float
end

推荐第一种，不会删除数据。

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转载自blog.csdn.net/bingfengjiyi23/article/details/78722607

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