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How to convert an entire MySQL database characterset and collation to UTF-8?
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Use the ALTER DATABASE and ALTER TABLE commands.
ALTER DATABASE databasename CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
ALTER TABLE tablename CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
Or if you're still on MySQL 5.5.2 or older which di...
How to print the full traceback without halting the program?
... are automatically reclaimed when garbage collection is enabled and they become unreachable, but it remains more efficient to avoid creating cycles.
On the other hand, by allowing you to access the traceback associated with an exception, Python 3 produce a less surprising result:
import traceb...
Java - get pixel array from image
...sue, the first method is absolutely not the way to go. The getRGB() method combines the alpha, red, green and blue values into one int and then returns the result, which in most cases you'll do the reverse to get these values back.
The second method will return the red, green and blue values direct...
Calculate business days
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Here's a function from the user comments on the date() function page in the PHP manual. It's an improvement of an earlier function in the comments that adds support for leap years.
Enter the starting and ending dates, along with an array of any holidays th...
What is the point of a private pure virtual function?
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The question in the topic suggest a pretty common confusion. The confusion is common enough, that C++ FAQ advocated against using private virtuals, for a long time, because confusion seemed to be a bad thing.
So to get rid of the confusion first: Yes, private virtual...
Why isn't sizeof for a struct equal to the sum of sizeof of each member?
... state that structure alignment is implementation-defined. Therefore each compiler may choose to align data differently, resulting in different and incompatible data layouts. For this reason, when dealing with libraries that will be used by different compilers, it is important to understand how th...
When do you use Java's @Override annotation and why?
...de a method for two benefits. Do it so that you can take advantage of the compiler checking to make sure you actually are overriding a method when you think you are. This way, if you make a common mistake of misspelling a method name or not correctly matching the parameters, you will be warned tha...
What requirement was the tuple designed to solve?
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When writing programs it is extremely common to want to logically group together a set of values which do not have sufficient commonality to justify making a class.
Many programming languages allow you to logically group together a set of otherwise unrelated v...
SqlException from Entity Framework - New transaction is not allowed because there are other threads
...ach (RivWorks.Model.NegotiationAutos.Client client in clientList)
{
var companyFeedDetailList = from a in _dbRiv.AutoNegotiationDetails where a.ClientID == client.ClientID select a;
// ...
}
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How can I check if a program exists from a Bash script?
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Answer
POSIX compatible:
command -v <the_command>
Example use:
if ! command -v COMMAND &> /dev/null
then
echo "COMMAND could not be found"
exit
fi
For Bash specific environments:
hash <the_command> # For regul...