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Cron job every three days
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The answer is not correct because neither suggestion actually runs the job every 3 days. 0 0 */3 * * means run on the 1st, 4th, 7th, etc. (*/3 means 1-31/3 means 1,4,7...31) so the gap will be smaller at the end of the month. (It'll run 2 days in a row if the previous month had 3...
What happens when a duplicate key is put into a HashMap?
...laces the previous value associated with the given key in the map (conceptually like an array indexing operation for primitive types).
The map simply drops its reference to the value. If nothing else holds a reference to the object, that object becomes eligible for garbage collection. Additionall...
Check time difference in Javascript
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I know this is ancient, but where in all this gibberish does anything get read from form fields? All I see is some hard-coded example code. How do I get the difference between whatever times my user typed into my two input type="text" boxes, rather than between ...
Changing MongoDB data store directory
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The short answer is that the --dbpath parameter in MongoDB will allow you to control what directory MongoDB reads and writes it's data from.
mongod --dbpath /usr/local/mongodb-data
Would start mongodb and put the files in /usr/local/mongodb-data.
Depending on your distribution and...
Entity Framework - Code First - Can't Store List
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This is the only really correct answer IMHO. All the others require you to change your model, and that violates the principle that domain models should be persistence ignorant. (It is fine if you are using separate persistence and domain model...
Is there a function to make a copy of a PHP array to another?
...ewLarsson raises a point in the comments below. PHP has a special feature called "references". They are somewhat similar to pointers in languages like C/C++, but not quite the same. If your array contains references, then while the array itself is passed by copy, the references will still resolve to...
How do I convert Word files to PDF programmatically? [closed]
I have found several open-source/freeware programs that allow you to convert .doc files to .pdf files, but they're all of the application/printer driver variety, with no SDK attached.
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What's the use of session.flush() in Hibernate
...hanges to the database). By default, Hibernate will flush changes automatically for you:
before some query executions
when a transaction is committed
Allowing to explicitly flush the Session gives finer control that may be required in some circumstances (to get an ID assigned, to control the si...
Why does Google +1 record my mouse movements? [closed]
...0);
c = c * b % d;
if (previousMouseMoveHandler) previousMouseMoveHandler.call(arguments);
d is (screen.width * screen.width + screen.height) * 1000000, and c is a variable that starts out as 1.
All of this is wrapped in the scope of an anonymous function, which itself is immediately evaluated to...
Is it fine to have foreign key as primary key?
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Foreign keys are almost always "Allow Duplicates," which would make them unsuitable as Primary Keys.
Instead, find a field that uniquely identifies each record in the table, or add a new field (either an auto-incrementing integer or a GUID) to act as the p...