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Possible to do a MySQL foreign key to one of two possible tables?
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What you're describing is called Polymorphic Associations. That is, the "foreign key" column contains an id value that must exist in one of a set of target tables. Typically the target tables are related in some way, such as being instances of some c...
Using querySelector with IDs that are numbers
...haracter 1 is U+0031, so you would escape it as \000031 or \31 .
Basically, to escape any numeric character, just prefix it with \3 and append a space character ( ). Yay Unicode!
So your code would end up as (CSS first, JS second):
#\31 {
background: hotpink;
}
document.getElementById(...
What is a stack trace, and how can I use it to debug my application errors?
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In simple terms, a stack trace is a list of the method calls that the application was in the middle of when an Exception was thrown.
Simple Example
With the example given in the question, we can determine exactly where the exception was thrown in the application. Let's have a lo...
How to refresh an IFrame using Javascript?
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answered Jan 14 '10 at 14:45
kjagiellokjagiello
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How do I check CPU and Memory Usage in Java?
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If you are looking specifically for memory in JVM:
Runtime runtime = Runtime.getRuntime();
NumberFormat format = NumberFormat.getInstance();
StringBuilder sb = new StringBuilder();
long maxMemory = runtime.maxMemory();
long allocatedMemory = runtime...
Pointers vs. values in parameters and return values
... function values, and interface values are implemented with pointers internally, and a pointer to them is often redundant.
Elsewhere, use pointers for big structs or structs you'll have to change, and otherwise pass values, because getting things changed by surprise via a pointer is confusing.
O...
What is the Scala identifier “implicitly”?
...Implicit Views). In this case, the compiler looks for implicit members, locally defined in the current or enclosing scopes, inherited, or imported, that are either Functions from the type of that the.prefix to a type with selection defined, or equivalent implicit methods.
scala> 1.min(2) // Int ...
Benefits of prototypal inheritance over classical?
So I finally stopped dragging my feet all these years and decided to learn JavaScript "properly". One of the most head-scratching elements of the languages design is it's implementation of inheritance. Having experience in Ruby, I was really happy to see closures and dynamic typing; but for the li...
What are the main disadvantages of Java Server Faces 2.0?
...ts which seem to make development much faster than with ASP.NET MVC, especially on AJAX-heavy sites. Integration testing looked very nice too.
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PHP parse/syntax errors; and how to solve them
...as T_STRING explains which symbol the parser/tokenizer couldn't process finally. This isn't necessarily the cause of the syntax mistake, however.
It's important to look into previous code lines as well. Often syntax errors are just mishaps that happened earlier. The error line number is just where ...