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How do I perform the SQL Join equivalent in MongoDB?
...rect. The new $lookup operator added to the aggregation pipeline is essentially identical to a left outer join:
https://docs.mongodb.org/master/reference/operator/aggregation/lookup/#pipe._S_lookup
From the docs:
{
$lookup:
{
from: <collection to join>,
localField: <...
What are Aggregates and PODs and how/why are they special?
... virtual functions (10.3).
So, OK, let's parse this definition. First of all, any array is an aggregate. A class can also be an aggregate if… wait! nothing is said about structs or unions, can't they be aggregates? Yes, they can. In C++, the term class refers to all classes, structs, and unions....
GetProperties() to return all properties for an interface inheritance hierarchy
...e is no need for recursion or queues since GetInterfaces() already returns all of the interfaces implemented by a type. As noted by Marc, there is no hierarchy, so why should we have to "recurse" on anything?
– glopes
Aug 8 '15 at 16:54
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How do I clear all options in a dropdown box?
...
You can use the following to clear all the elements.
var select = document.getElementById("DropList");
var length = select.options.length;
for (i = length-1; i >= 0; i--) {
select.options[i] = null;
}
...
C++ project organisation (with gtest, cmake and doxygen)
...rs are the
basis for users to interact with what you offer and must be
installed. This means they have to be in a subdirectory (no-one wants
lots of headers ending up in top-level /usr/include/) and your
headers must be able to include themselves with such a setup.
└── prj
├── inclu...
How can I list all the deleted files in a Git repository?
...See Find and restore a deleted file in a Git repository
If you don't want all the information about which commit they were removed in, you can just add a grep delete in there.
git log --diff-filter=D --summary | grep delete
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How to find foreign key dependencies in SQL Server?
How can I find all of the foreign key dependencies on a particular column?
13 Answers
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View list of all JavaScript variables in Google Chrome Console
In Firebug, the DOM tab shows a list of all your public variables and objects. In Chrome's console you have to type the name of the public variable or object you want to explore.
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How to create the most compact mapping n → isprime(n) up to a limit N?
Naturally, for bool isprime(number) there would be a data structure I could query.
I define the best algorithm , to be the algorithm that produces a data structure with lowest memory consumption for the range (1, N], where N is a constant.
Just an example of what I am looking for: I could rep...
Remove sensitive files and their commits from Git history
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For all practical purposes, the first thing you should be worried about is CHANGING YOUR PASSWORDS! It's not clear from your question whether your git repository is entirely local or whether you have a remote repository elsewhere...