大约有 40,000 项符合查询结果（耗时：0.0398秒） [XML]
Is there a Boolean data type in Microsoft SQL Server like there is in MySQL? [duplicate]
...compared using a comparison operator such as =, <> or IS NULL. e.g.
SELECT
a.answer_body
FROM answers AS a
WHERE a.is_accepted = 0;
From a formatting perspective, a bit value is typically displayed as 0 or 1 in client software. When a more user-friendly format is required, and it can't ...
Why shouldn't I use mysql_* functions in PHP?
... 5.5 and above)
$link = mysql_connect('localhost', 'user', 'pass');
mysql_select_db('testdb', $link);
mysql_set_charset('UTF-8', $link);
With PDO: All you need to do is create a new PDO object. The constructor accepts parameters for specifying the database source PDO's constructor mostly takes fo...
Difference between string and text in rails?
... load varchar in one go, but store text (and blob) outside of the table. A SELECT name, amount FROM products could, be a lot slower when using text for name than when you use varchar. And since Rails, by default loads records with SELECT * FROM... your text-columns will be loaded. This will probably...
In Python, when to use a Dictionary, List or Set?
...om a sequence, and computing mathematical operations such as intersection, union, difference, and symmetric difference.
share
|
improve this answer
|
follow
|
...
Calling C++ class methods via a function pointer
...ion pointer and initialize to NULL
int (TMyClass::*pt2ConstMember)(float, char, char) const = NULL;
// C++
class TMyClass
{
public:
int DoIt(float a, char b, char c){ cout << "TMyClass::DoIt"<< endl; return a+b+c;};
int DoMore(float a, char b, char c) const
{ cout <&...
“Large data” work flows using pandas
...ns?
What will typical operations look like. E.g. do a query on columns to select a bunch of rows and specific columns, then do an operation (in-memory), create new columns, save these.
(Giving a toy example could enable us to offer more specific recommendations.)
After that processing, then what do...
In C/C++ what's the simplest way to reverse the order of bits in a byte?
...
This should work:
unsigned char reverse(unsigned char b) {
b = (b & 0xF0) >> 4 | (b & 0x0F) << 4;
b = (b & 0xCC) >> 2 | (b & 0x33) << 2;
b = (b & 0xAA) >> 1 | (b & 0x55) << 1;
retu...
Are there disadvantages to using a generic varchar(255) for all text-based fields?
...e , town , country , phone number etc, all of which are defined as VARCHAR(255) even though none of these fields will ever come close to having 255 characters. (If you're wondering, it's this way because Ruby on Rails migrations map String fields to VARCHAR(255) by default and I never bothe...
Why is “while ( !feof (file) )” always wrong?
...e is again std::cin, just as before.
POSIX, write(2) to flush a buffer:
char const * p = buf;
ssize_t n = bufsize;
for (ssize_t k = bufsize; (k = write(fd, p, n)) > 0; p += k, n -= k) {}
if (n != 0) { /* error, failed to write complete buffer */ }
The result we use here is k, the numb...
Any way to make a WPF textblock selectable?
How to allow TextBlock 's text to be selectable?
15 Answers
15
...