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E11000 duplicate key error index in mongodb mongoose
...nt with the sparse index to filter these null values from the unique index and avoid the error.
unique indexes
Sparse indexes only contain entries for documents that have the indexed field, even if the index field contains a null value.
In other words, a sparse index is ok with multiple documents...
What's the syntax for mod in java
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Careful with the terms mod and modular because n (mod m) IS ALWAYS >= 0 but not n % m. n % m is in the range > -m and < m. Although Java has a remainder operator for int and long types, it has no modulus function or operator. I.e., -12 % 10 = ...
Find running median from a stream of integers
...n left side to represent elements that are less than the effective median, and a min heap on right side to represent elements that are greater than the effective median.
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Integrating MySQL with Python in Windows
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Download page for python-mysqldb. The page includes binaries for 32 and 64 bit versions of for Python 2.5, 2.6 and 2.7.
There's also discussion on getting rid of the deprecation warning.
UPDATE: This is an old answer. Currently, I would recommend using PyMySQL. It's pure python, so it supp...
The input is not a valid Base-64 string as it contains a non-base 64 character
I have a REST service that reads a file and sends it to another console application after converting it to Byte array and then to Base64 string. This part works, but when the same stream is received at the application, it gets manipulated and is no longer a valid Base64 string. Some junk characters ...
Xcode/Simulator: How to run older iOS version?
...s in your binary you will not be able to run it on anything before iOS 4.0 and it will be rejected if you try and submit a binary like this.
You can still run the simulator from 3.2 onwards after upgrading.
In the iPhone Simulator try selecting Hardware -> Version -> 3.2
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Optional Methods in Java Interface
From my understanding if you implement an interface in java, the methods specified in that interface have to be used by the sub classes implementing the said interface.
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.keyCode vs. .which
... The answer below was written in 2010. Here many years later, both keyCode and which are deprecated in favor of key (for the logical key) and code (for the physical placement of the key). But note that IE doesn't support code, and its support for key is based on an older version of the spec so isn't...
MongoDB and “joins” [duplicate]
...ll only be evaluated when needed. A join (in a SQL database) on the other hand will resolve relationships and return them as if they were a single table (you "join two tables into one").
You can read more about DBRef here:
http://docs.mongodb.org/manual/applications/database-references/
There are ...
When is a function too long? [closed]
...t? I'm asking because I have a function with 60 lines (including comments) and was thinking about breaking it apart.
24 Ans...