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What good are SQL Server schemas?
I'm no beginner to using SQL databases, and in particular SQL Server. However, I've been primarily a SQL 2000 guy and I've always been confused by schemas in 2005+. Yes, I know the basic definition of a schema, but what are they really used for in a typical SQL Server deployment?
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Image fingerprint to compare similarity of many images
...produce a normative mapping of the image data - store this with each image and then compare just the fingerprints. This is a complex algorithm and not for the faint of heart.
a few simple solutions are possible:
Create a luminosity histogram for the image as a fingerprint
Create scaled down versi...
What is an undefined reference/unresolved external symbol error and how do I fix it?
...efined reference/unresolved external symbol errors? What are common causes and how to fix/prevent them?
34 Answers
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Prefer composition over inheritance?
...this case, it makes sense to extract it out as an interface / class / both and make it a member of both classes.
Update: Just came back to my answer and it seems now that it is incomplete without a specific mention of Barbara Liskov's Liskov Substitution Principle as a test for 'Should I be inher...
How do I debug an MPI program?
I have an MPI program which compiles and runs, but I would like to step through it to make sure nothing bizarre is happening. Ideally, I would like a simple way to attach GDB to any particular process, but I'm not really sure whether that's possible or how to do it. An alternative would be having ea...
How to know if two arrays have the same values
...have these two arrays: one is filled with information from an ajax request and another stores the buttons the user clicks on. I use this code (I filled with sample numbers):
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How to detect if a script is being sourced
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This seems to be portable between Bash and Korn:
[[ $_ != $0 ]] && echo "Script is being sourced" || echo "Script is a subshell"
A line similar to this or an assignment like pathname="$_" (with a later test and action) must be on the first line of the s...
Implementation difference between Aggregation and Composition in Java
I'm aware of the conceptual differences between Aggregation and Composition. Can someone tell me the implementation difference in Java between them with examples?
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Python class inherits object
...erit from object?
In Python 3, apart from compatibility between Python 2 and 3, no reason. In Python 2, many reasons.
Python 2.x story:
In Python 2.x (from 2.2 onwards) there's two styles of classes depending on the presence or absence of object as a base-class:
"classic" style classes: the...
Unit testing code with a file system dependency
...at you clean up after youself -- delete any temporary files you created -- and that you don't accidentally overwrite an existing file that happened to have the same filename as a temporary file you were using. Always use relative paths and not absolute paths.
It would also be a good idea to chdir(...