大约有 40,000 项符合查询结果（耗时：0.0383秒） [XML]
Insert into a MySQL table or update if exists
...
Check out REPLACE
http://dev.mysql.com/doc/refman/5.0/en/replace.html
REPLACE into table (id, name, age) values(1, "A", 19)
share
|
improve this answe...
Best Practices: Salting & peppering passwords?
...e that someone with some security experience supports this method. Would a MySQL AES_ENCRYPT($passwordHash, $serverSideKey) call also be an appropriate way of implementing this?
– foochow
Jun 27 '13 at 19:40
...
How to get disk capacity and free space of remote computer
...t Win32_LogicalDisk -ComputerName remotecomputer -Filter "DeviceID='C:'" |
Select-Object Size,FreeSpace
$disk.Size
$disk.FreeSpace
To extract the values only and assign them to a variable:
$disk = Get-WmiObject Win32_LogicalDisk -ComputerName remotecomputer -Filter "DeviceID='C:'" |
Foreach-Obje...
What's the “average” requests per second for a production web application?
...age 200-300 connections per second. Spiking to 800 connections per second.
MySQL handled 2,400 requests per second.
180 Rails instances. Uses Mongrel as the "web" server.
1 MySQL Server (one big 8 core box) and 1 slave. Slave is read only for statistics and reporting.
30+ processes for handling odd ...
Do I need to create indexes on foreign keys on Oracle?
...ance of an index may be unacceptable.
Most salient here would seem to be selectivity: if the values in the index would be highly duplicated then it may give better performance to drop the index (if possible) and allow a table scan.
...
Differences between utf8 and latin1
...w a bit Java).
Note that full 4-byte UTF-8 support was only introduced in MySQL 5.5. Before that version, it only goes up to 3 bytes per character, not 4 bytes per character. So, it supported only the BMP plane and not e.g. the Emoji plane. If you want full 4-byte UTF-8 support, upgrade MySQL to at...
How do I convert between big-endian and little-endian values in C++?
...wap_endian(T u)
{
static_assert (CHAR_BIT == 8, "CHAR_BIT != 8");
union
{
T u;
unsigned char u8[sizeof(T)];
} source, dest;
source.u = u;
for (size_t k = 0; k < sizeof(T); k++)
dest.u8[k] = source.u8[sizeof(T) - k - 1];
return dest.u;
}
us...
How to flatten tree via LINQ?
...IEnumerable<MyNode> Flatten(IEnumerable<MyNode> e) =>
e.SelectMany(c => Flatten(c.Elements)).Concat(new[] { e });
You can then filter by group using Where(...).
To earn some "points for style", convert Flatten to an extension function in a static class.
public static IEnume...
Android studio add external project to build.gradle
...ick module -> Open Module Settings -> Dependencies -> + (bottom), select Module Dependency, select your library from the list, click ok :)
– T.Coutlakis
Jan 11 '15 at 22:51
...
MySQL Update Inner Join tables query
I have no idea what the problem is. Using MySQL 5.0 I get a compile error when attempting to run the following MySQL update query:
...