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What's wrong with nullable columns in composite primary keys?
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Primary keys are for uniquely identifying rows. This is done by comparing all parts of a key to the input.
Per definition, NULL cannot be part of a successful comparison. Even a comparison to itself (NULL = NULL) will fail. This means a key containing NULL would not work.
Additonally, NULL is al...
Trusting all certificates with okHttp
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Just in case anyone falls here, the (only) solution that worked for me is creating the OkHttpClient like explained here.
Here is the code:
private static OkHttpClient getUnsafeOkHttpClient() {
try {
// Create a trust manager that does not...
Difference between . and : in Lua
...nly once. In this case, there's a clear difference between obj.method(obj, etc) and obj:method(etc).
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How to get a subset of a javascript object's properties
...og(picked); // { a: 5, c: 7 }
From Philipp Kewisch:
This is really just an anonymous function being called instantly. All of this can be found on the Destructuring Assignment page on MDN. Here is an expanded form
let unwrap = ({a, c}) => ({a, c});
let unwrap2 = function({a, ...
Bash Templating: How to build configuration files from templates with Bash?
...\}/defined $ENV{$1} ? $ENV{$1} : $&/eg' < template.txt
to replace all ${...} strings with corresponding enviroment variables (do not forget to export them before running this script).
For pure bash this should work (assuming that variables do not contain ${...} strings):
#!/bin/bash
while...
Genymotion, “Unable to load VirtualBox engine.” on Mavericks. VBox is setup correctly
...nces->Security and Privacy->General (You'll get a popup when you install VirtualBox).
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C++应用程序添加VBScript和JavaScript支持 - C/C++ - 清泛网移动版 - 专注IT技能提升
...endencies on MFC and can also be used in a console application.
First of all to call a script it is important to know that VBScript and JScript deal only with VARIANT parameters. This is the reason I created the CSafeArrayHelper class. The CSafeArray helper wrapper class allows you to create param...
C++应用程序添加VBScript和JavaScript支持 - C/C++ - 清泛网移动版 - 专注IT技能提升
...endencies on MFC and can also be used in a console application.
First of all to call a script it is important to know that VBScript and JScript deal only with VARIANT parameters. This is the reason I created the CSafeArrayHelper class. The CSafeArray helper wrapper class allows you to create param...
C++应用程序添加VBScript和JavaScript支持 - C/C++ - 清泛网移动版 - 专注IT技能提升
...endencies on MFC and can also be used in a console application.
First of all to call a script it is important to know that VBScript and JScript deal only with VARIANT parameters. This is the reason I created the CSafeArrayHelper class. The CSafeArray helper wrapper class allows you to create param...
C++应用程序添加VBScript和JavaScript支持 - C/C++ - 清泛网移动版 - 专注IT技能提升
...endencies on MFC and can also be used in a console application.
First of all to call a script it is important to know that VBScript and JScript deal only with VARIANT parameters. This is the reason I created the CSafeArrayHelper class. The CSafeArray helper wrapper class allows you to create param...