大约有 40,000 项符合查询结果（耗时：0.0565秒） [XML]
Why do we always prefer using parameters in SQL statements?
...uld be
SELECT empSalary from employee where salary = 0 or 1=1
whereby all empSalaries would be returned.
Further, a user could perform far worse commands against your database, including deleting it If they wrote 0; Drop Table employee:
SELECT empSalary from employee where salary = 0; Drop Ta...
If table exists drop table then create it, if it does not exist just create it
...s case than not to cover, see locking note below).
Second RENAME ... atomically replaces table definition, refer to
MySQL manual
for details.
At last, DROP ... just cleans up the old table,
obviously.
Wrapping all statements with something like SELECT GET_LOCK('__upgrade', -1); ... DO RELEASE_LOCK...
Can you add new statements to Python's syntax?
... a hands-on approach here: I'm going to add an until statement to Python.
All the coding for this article was done against the cutting-edge Py3k branch in the Python Mercurial repository mirror.
The until statement
Some languages, like Ruby, have an until statement, which is the complement to whi...
Use of #pragma in C
...take some action, override some default, etc. that may or may not apply to all machines and operating systems.
See msdn for more info.
share
|
improve this answer
|
follow
...
Python: Tuples/dictionaries as keys, select, sort
...es and so on.
I'd like to organize them in a data structure in Python that allows for easy selection and sorting. My idea was to put them into a dictionary with tuples as keys, e.g.,
...
What are the calling conventions for UNIX & Linux system calls (and user-space functions) on i386 an
Following links explain x86-32 system call conventions for both UNIX (BSD flavor) & Linux:
4 Answers
...
Removing duplicate objects with Underscore for Javascript
...
.uniq/.unique accepts a callback
var list = [{a:1,b:5},{a:1,c:5},{a:2},{a:3},{a:4},{a:3},{a:2}];
var uniqueList = _.uniq(list, function(item, key, a) {
return item.a;
});
// uniqueList = [Object {a=1, b=5}, Object {a=2}, Object {a=3}, Object ...
How to read a single character from the user?
... except ImportError:
self.impl = _GetchUnix()
def __call__(self): return self.impl()
class _GetchUnix:
def __init__(self):
import tty, sys
def __call__(self):
import sys, tty, termios
fd = sys.stdin.fileno()
old_settings = termios.tcge...
How do I print the elements of a C++ vector in GDB?
...o have gdb 7 (I tested it on gdb 7.01) and some python pretty-printer. Installation process of these is described on gdb wiki.
What is more, after installing above, this works well with Eclipse C++ debugger GUI (and any other IDE using GDB, as I think).
...
Access nested dictionary items via a list of keys?
...ist, value):
getFromDict(dataDict, mapList[:-1])[mapList[-1]] = value
All but the last element in mapList is needed to find the 'parent' dictionary to add the value to, then use the last element to set the value to the right key.
Demo:
>>> getFromDict(dataDict, ["a", "r"])
1
>>&g...