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mongoDB/mongoose: unique if not null
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Just a quick update to those researching this topic.
The selected answer will work, but you might want to consider using partial indexes instead.
Changed in version 3.2: Starting in MongoDB 3.2, MongoDB provides the
option to create partial indexes. Partial indexes offer a su...
Why do we need message brokers like RabbitMQ over a database like PostgreSQL?
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PostgreSQL 9.5
PostgreSQL 9.5 incorporates SELECT ... FOR UPDATE ... SKIP LOCKED. This makes implementing working queuing systems a lot simpler and easier. You may no longer require an external queueing system since it's now simple to fetch 'n' rows that no other sess...
Cross browser JavaScript (not jQuery…) scroll to top animation
...rollTo(document.body, 0, 600);
}
var scrollme;
scrollme = document.querySelector("#scrollme");
scrollme.addEventListener("click",runScroll,false)
function scrollTo(element, to, duration) {
if (duration <= 0) return;
var difference = to - element.scrollTop;
var perTick = difference...
Difference between Rebuild and Clean + Build in Visual Studio
..., right click on the desired project name in the Solution Explorer tab and select Set as StartUp project. The project name now appears in bold. Since the homework solutions typically have only one project, Build or Rebuild Solution is effectively the same as Build or Rebuild .
Compile just compiles...
Convert list of dictionaries to a pandas DataFrame
...o extract only the 0th and 2nd rows from data2 above, you can use:
rows_to_select = {0, 2}
for i in reversed(range(len(data2))):
if i not in rows_to_select:
del data2[i]
pd.DataFrame(data2)
# pd.DataFrame.from_dict(data2)
# pd.DataFrame.from_records(data2)
A B C D E
0 5...
What are all the user accounts for IIS/ASP.NET and how do they differ?
...nymous Authentication entry:
Ensure that "Application pool identity" is selected:
When you come to apply file and folder permissions you grant the Application Pool identity whatever rights are required. For example if you are granting the application pool identity for the ASP.NET v4.0 pool per...
How to add a custom button state
...tion indicated by @(Ted Hopp) works, but needs a little correction: in the selector, the item states need an "app:" prefix, otherwise the inflater won't recognise the namespace correctly, and will fail silently; at least this is what happens to me.
Allow me to report here the whole solution, with s...
How do you test private methods with NUnit?
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This should be the selected answer, as it is the only one which actually answers the question.
– bavaza
Dec 10 '13 at 16:04
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When to use Hadoop, HBase, Hive and Pig?
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Consider that you work with RDBMS and have to select what to use - full table scans, or index access - but only one of them.
If you select full table scan - use hive. If index access - HBase.
s...
How to organize a node app that uses sequelize?
... did not quite understand Sequelize, but to me doing things more than just selecting from one table wasn't really convenient. And where ordinarily you would use select from two or more tables, or a union in pure SQL, you would have to run separate queries, and with the async nature of Node it's just...