Numberlong(x) 和 Numberlong(“x") 之间的差异 [英] Diference between Numberlong(x) and Numberlong("x")

问题描述

我在 MongoDB 数据库中存储了一些 XML 数据.一些数据存储为 Numberlong(1234)，另一些存储为 Numberlong("12353").示例:

I stored some XML data in MongoDB databse. Some of the data is stored as Numberlong(1234) and some other as Numberlong("12353"). Example:

"nodes_id" : [
    NumberLong(13879272),
    NumberLong(252524625),
    NumberLong(252524611),
    NumberLong(252524630),
    NumberLong(149809404),
    NumberLong(605181143),
    NumberLong("3068489546"),
    NumberLong("3059300418"),
    NumberLong(253351454),
    NumberLong(253351438),
    NumberLong(253348623),
    NumberLong(253351472)
]

这两种类型有什么区别吗?

Is there any difference between the two types?

推荐答案

NumberLong(253351454) 仅适用于足够小的数字，它们不需要......: shell 必须以某种方式在 JS 中表示它们，所以它只能表示

NumberLong(253351454) only works for numbers that are small enough that they don't need to be ... well, long: The shell must represent them in JS somehow, so it can only represent numbers that

对于较大的数字，需要文本表示，因为没有足够大的数据类型可用，因此 NumberLong("3059300418") 和 3059300418 >253351454.

For larger numbers, a textual representation is required because there's no large enough data type available, hence NumberLong("3059300418") with 3059300418 > 253351454.

换句话说，不，没有区别.这只是 shell 的限制，或者更一般地说，是 JS 和浮点数的限制.

In other words, no, there's no difference. It's just a limitation of the shell, or more generally speaking, of JS and floating point numbers.

警告:不要尝试用太大的数字调用构造函数，即不要尝试 db.foo.insert({"t" : NumberLong(1234657890132456789)});这个数字对于双精度来说太大了，它会导致舍入错误.上面的数字会被转换成NumberLong("1234657890132456704")，这显然是错误的.

Caveat: Don't try to invoke the constructor with a too large number, i.e. don't try db.foo.insert({"t" : NumberLong(1234657890132456789)}); Since that number is way too large for a double, it will cause roundoff errors. Above number would be converted to NumberLong("1234657890132456704"), which is wrong, obviously.

这篇关于Numberlong(x) 和 Numberlong(“x") 之间的差异的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！