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Primary key/foreign Key naming convention [closed]
...e the USING syntax in SQL to save some typing and some boilerplate noise:
SELECT name, address, amount
FROM employees JOIN payroll USING (employee_id)
Another argument in favor of convention #2 is that it's the way the relational model was designed.
The significance of each column is
part...
How do you properly determine the current script directory in Python?
...ing to get.
It's unusual to be executing a script with exec/execfile; normally you should be using the module infrastructure to load scripts. If you must use these methods, I suggest setting __file__ in the globals you pass to the script so it can read that filename.
There's no other way to get th...
Are duplicate keys allowed in the definition of binary search trees?
...cluded. For example, the example algorithms in the MIT Algorithms book usually present examples without duplicates. It is fairly trivial to implement duplicates (either as a list at the node, or in one particular direction.)
Most (that I've seen) specify left children as <= and right children ...
Generic deep diff between two objects
... },
isFunction: function (x) {
return Object.prototype.toString.call(x) === '[object Function]';
},
isArray: function (x) {
return Object.prototype.toString.call(x) === '[object Array]';
},
isDate: function (x) {
return Object.prototype.toString.call(x) === '[ob...
django change default runserver port
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You can't run the development server programmatically, so a custom command won't work unless it calls the shell using something like call. If this solution works for you please make sure to mark it as solved.
– Pablo Albornoz
May 13 '1...
Pass a data.frame column name to a function
...(x[,column])
}
fun1(df, "B", max)
Alternatively, using [[ also works for selecting a single column at a time:
df <- data.frame(A=1:10, B=2:11, C=3:12)
fun1 <- function(x, column){
max(x[[column]])
}
fun1(df, "B")
...
Getting “cannot find Symbol” in Java project in Intellij
...
Select Build->Rebuild Project will solve it
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How to find out if you're using HTTPS without $_SERVER['HTTPS']
...PHP as a Fast-CGI application).
Also, Apache 1.x servers (and broken installations) might not have $_SERVER['HTTPS'] defined even if connecting securely. Although not guaranteed, connections on port 443 are, by convention, likely using secure sockets, hence the additional port check.
Additional n...
How can I inspect disappearing element in a browser?
...
An alternative method in Chrome:
Open devTools (F12).
Select the "Sources" tab.
While the element you want is displayed, press F8 (or Ctrl+/). This will break script execution and "freeze" the DOM exactly as it is displayed.
From this point, use Ctrl+Shift+C to select the elemen...
Update MongoDB field using value of another field
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The best way to do this is in version 4.2+ which allows using of aggregation pipeline in the update document and the updateOne, updateMany or update collection method. Note that the latter has been deprecated in most if not all languages drivers.
MongoDB 4.2+
Version 4.2 ...