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MySQL error: key specification without a key length
I have a table with a primary key that is a varchar(255). Some cases have arisen where 255 characters isn't enough. I tried changing the field to a text, but I get the following error:
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How to check for valid email address? [duplicate]
...TLD to alphanumeric right now (still haven't seen a TLD that has non-ASCII chars). Using this now: re.compile(r"[^@\s]+@[^@\s]+\.[a-zA-Z0-9]+$")
– gaefan
Aug 29 '15 at 15:39
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What do 'real', 'user' and 'sys' mean in the output of time(1)?
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(Ran out of chars in the prev comment so): More detail? Use perf [1], [2]. [1] perf.wiki.kernel.org/index.php/Main_Page [2] brendangregg.com/perf.html
– kaiwan
May 9 '15 at 7:46
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In C, do braces act as a stack frame?
...stack frame. Otherwise, you would not be able to do something like this:
char var = getch();
{
char next_var = var + 1;
use_variable(next_char);
}
If curly braces caused a true stack push/pop (like a function call would), then the above code would not compile because the ...
How to convert int to QString?
...t might very well work but internally, the operator+(const QString &s, char c) implementation is called, and the string wont contain the integer as number but its QChar::fromAscii(c) equivalent
– x29a
Jul 23 '15 at 8:19
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Type erasure techniques
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I would also consider (similar to void*) the use of "raw storage": char buffer[N].
In C++0x you have std::aligned_storage<Size,Align>::type for this.
You can store anything you want in there, as long as it's small enough and you deal with the alignment properly.
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How can I capitalize the first letter of each word in a string?
... If the optional second argument sep is absent or None, runs of whitespace characters are replaced by a single space and leading and trailing whitespace are removed, otherwise sep is used to split and join the words.
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Check if a string contains a string in C++
...lt;chrono>
std::string randomString( size_t len );
int main(int argc, char* argv[])
{
using namespace std::chrono;
const size_t haystacksCount = 200000;
std::string haystacks[haystacksCount];
std::string needle = "hello";
bool sink = true;
high...
Can I have multiple primary keys in a single table?
...r example:
CREATE TABLE userdata (
userid INT,
userdataid INT,
info char(200),
primary key (userid, userdataid)
);
Update: Here is a link with a more detailed description of composite primary keys.
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Legality of COW std::string implementation in C++11
...be seen in the following if COW were allowed: std::string a("something"); char& c1 = a[0]; std::string b(a); char& c2 = a[1]; c1 is a reference to a. You then "copy" a. Then, when you attempt to take the reference the second time, it has to make a copy to get a non-const reference since...