从控制台将MongoDB字段的类型更改为整数 [英] Change the type of a MongoDB field to integer from its console

问题描述

我们有一个应用程序在MongoDB中存储来自C / C ++的一些配置值，并且能够重新启动（即它运行一段时间，有人中断应用程序，更改配置，然后再次运行应用程序，以及它从它停止的地方回来）。这就像布尔值和字符串配置的魅力一样。

We have an application that stores some configuration values from C/C++ in MongoDB and has the capability to be restarted (i.e. it runs for a while, someone interrupts the application, changes the configuration, then runs the app again, and it picks up where it left off). This works like a charm for boolean and string configurations.

但是我们有一些整数（在我们当前的C / C ++实现中 - 32位值）。当我使用MongoDB控制台修改这些整数值时，Mongo总是将它们存储为Number（在C / C ++实现中是可靠的）。我们将更改应用程序以获取期望整数的双值，但我想知道是否有办法强制Mongo从其JavaScript控制台存储整数。

But then we have some integers (in our current C/C++ implementation - 32 bit values). And when I use the MongoDB console to modify those integer values, Mongo always stores them back as Number (which is doulble in the C/C++ implementation). We will change the app to take double values where it expects integers but I was wondering if there is a way to force Mongo to store integers from its JavaScript console.

任何建议？

推荐答案

在C / C ++意义上，整数是实际上并不保证为32位值。 int 必须至少为16位，但通常与平台架构匹配（例如32或64位）。

In the C/C++ "sense of the word", ints are not actually guaranteed to be 32-bit values. An int must be at least 16-bits, but generally matches the platform architecture (eg. 32 or 64bit).

如@Jasd所述，JavaScript只有一个数字类型，它是一个浮点（C中的 double ）。

As mentioned by @Jasd, JavaScript does only have one numeric type which is a floating point (double in C).

从MongoDB shell开始，您应该可以使用函数 NumberInt（..）来获取 BSON 32位整数值或 NumberLong（..）获取BSON 64位整数。

From the MongoDB shell you should be able to use the functions NumberInt(..) to get a BSON 32-bit integer value or NumberLong(..) to get a BSON 64-bit integer.

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