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Rails migration: t.references with alternative name?
...
You can do this all in the initial migration/column definition (at least currently in Rails 5):
t.references :transferable_as, index: true, foreign_key: {to_table: :courses}
t.references :same_as, index: true, foreign_key: {to_table: :cours...
using awk with column value conditions
...
All awk implementations support both "==" and "~".
– Ed Morton
Feb 7 '13 at 5:00
3
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Getting exact error type in from DbValidationException
...ity.Validation.DbEntityValidationResult} which gives me no information at all about what field it was unable to initialize.
Is there a way to get more info about this error?
...
Why is document.body null in my javascript?
...body hasn't been defined at this point yet. In general, you want to create all elements before you execute javascript that uses these elements. In this case you have some javascript in the head section that uses body. Not cool.
You want to wrap this code in a window.onload handler or place it after...
How is mime type of an uploaded file determined by browser?
...dden), and then if not found there, we defer to the system registry.
// Finally, we scan a secondary hard-coded list to catch types that we can
// deduce but that we also want to allow the OS to override.
The hard-coded lists come a bit earlier in the file: https://cs.chromium.org/chromium/src/net/...
Difference between namespace in C# and package in Java
...n java you have to import a class, not a package. It IS possible to import all classes in a package with an import package.* but that too imports the classes, not the package.
– Imus
May 23 '18 at 7:54
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ATL正则表达式库使用 - C/C++ - 清泛网 - 专注C/C++及内核技术
...f (!reUrl.Match( "http://search.microsoft.com/us/Search.asp?qu=atl&boolean=ALL#results",
&mcUrl))
{
// Unexpected error.
return 0;
}
for (UINT nGroupIndex = 0; nGroupIndex < mcUrl.m_uNumGroups;
++nGroupIndex)
{
const CAtlREMatchContext<>::RECHAR...
How to show line number when executing bash script
...ly executing.
If you need to know the line number where the function was called, try $BASH_LINENO. Note that this variable is an array.
For example:
#!/bin/bash
function log() {
echo "LINENO: ${LINENO}"
echo "BASH_LINENO: ${BASH_LINENO[*]}"
}
function foo() {
log "$@"
}
foo ...
String.replaceAll single backslashes with double backslashes
...he String \something\ into the String \\something\\ using replaceAll , but I keep getting all kinds of errors. I thought this was the solution:
...
Can I create more than one repository for github pages?
...tion, including options for using custom domain names.
(since April 2013, all username.github.com are now username.github.io)
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