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How do I update if exists, insert if not (AKA “upsert” or “merge”) in MySQL?
...ON DUPLICATE KEY UPDATE. For example:
INSERT INTO `usage`
(`thing_id`, `times_used`, `first_time_used`)
VALUES
(4815162342, 1, NOW())
ON DUPLICATE KEY UPDATE
`times_used` = `times_used` + 1
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Error: Could not create the Java Virtual Machine Mac OSX Mavericks
...he Mac 10.9.4. I then ran the command java -v in Terminal and I get this message:
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How to generate string of a certain length to insert into a file to meet a file size criteria?
I have a requirement to test some load issues with regards to file size. I have a windows application written in C# which will automatically generate the files. I know the size of each file, ex. 100KB, and how many files to generate. What I need help with is how to generate a string less than or ...
How are GCC and g++ bootstrapped?
This has been bugging me for a while. How do GCC and g++ compile themselves?
1 Answer
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Why isn't there a Guid.IsNullOrEmpty() method
This keeps me wondering why Guid in .NET does not have IsNullOrEmpty() method (where empty means all zeros)
6 Answers
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Numpy: Divide each row by a vector element
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Iteration over std::vector: unsigned vs signed index variable
...rating forwards is almost identical. Just change the iterators / swap decrement by increment. You should prefer iterators. Some people tell you to use std::size_t as the index variable type. However, that is not portable. Always use the size_type typedef of the container (While you could get away wi...
Map and Reduce in .NET
... reduce functions. C# 3.5 and Linq already has it albeit under different names.
Map is Select:
Enumerable.Range(1, 10).Select(x => x + 2);
Reduce is Aggregate:
Enumerable.Range(1, 10).Aggregate(0, (acc, x) => acc + x);
Filter is Where:
Enumerable.Range(1, 10).Where(x => x % 2 == 0);
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Avoiding SQL injection without parameters
We are having another discussion here at work about using parametrized sql queries in our code. We have two sides in the discussion: Me and some others that say we should always use parameters to safeguard against sql injections and the other guys that don't think it is necessary. Instead they want ...
Create directories using make file
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This would do it - assuming a Unix-like environment.
MKDIR_P = mkdir -p
.PHONY: directories
all: directories program
directories: ${OUT_DIR}
${OUT_DIR}:
${MKDIR_P} ${OUT_DIR}
This would have to be run in the top-level directory - or the definition of ${OUT_...