大约有 19,000 项符合查询结果（耗时：0.0315秒） [XML]
MySQL foreign key constraints, cascade delete
... When creating the tables, you need to specify InnoDB or another MySQL engine that's capable of CASCADE operations. Otherwise the MySQL default, MyISAM, will be used and MyISAM does not support CASCADE operations. To do this, just add ENGINE InnoDB before the last ;.
–...
Are there disadvantages to using a generic varchar(255) for all text-based fields?
...ould always store 255 characters.
But since you tagged this question with MySQL, I'll mention a MySQL-specific tip: as rows are copied from the storage engine layer to the SQL layer, VARCHAR fields are converted to CHAR to gain the advantage of working with fixed-width rows. So the strings in mem...
Find running median from a stream of integers
...Add next item to one of the heaps
if next item is smaller than maxHeap root add it to maxHeap,
else add it to minHeap
Step 2: Balance the heaps (after this step heaps will be either balanced or
one of them will contain 1 more item)
if number of elements in one of the heaps is greater ...
那些我印象深刻的建议和教诲 - 杂谈 - 清泛网 - 专注C/C++及内核技术
...负有心人”和“蠢”之间可能连窗户纸都没有，只看个人如何面对了。
多用Google吧
我工作的第一天，项目经理把我叫去说：给你们讲讲JUnit, SVN，Ant, JBuilder的用法，明天开始用。这四样东西我以前都没有接触过，第一反应就是...
What are file descriptors, explained in simple terms?
...
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
sleep 14726 root cwd DIR 8,1 4096 1201140 /home/x
sleep 14726 root rtd DIR 8,1 4096 2 /
sleep 14726 root txt REG 8,1 35000 786587 /bin/sleep
sleep 14726 root mem REG 8,1 11864720 118650...
Build tree array from flat array in javascript
...que id,
parentId : the id of the parent node (which is 0 if the node is a root of the tree)
level : the level of depth in the tree
...
MySQL Results as comma separated list
...
The intent is fine and MySQL will allow this, but be careful (generally) with your use of GROUP BY. The items in the select list need to be valid aggregates in the context of the GROUP BY clause. In this case, p.name is not strictly valid. Any d...
Implement touch using Python?
...
# Current directory which is "walked through"
# | Directories in root
# | | Files in root Working directory
# | | | |
for root, _, filenames in os.walk('.'):
for fname in filenames:
pathname = os.path.join(root, fname)
try:
os.utime(p...
Why is SSE scalar sqrt(x) slower than rsqrt(x) * x?
...th on an Intel Core Duo, and while looking at various approaches to square root I've noticed something odd: using the SSE scalar operations, it is faster to take a reciprocal square root and multiply it to get the sqrt, than it is to use the native sqrt opcode!
...
How do I adb pull ALL files of a folder present in SD Card
...
If you want to pull a folder owned by root, start an adb root session (using $ adb root).
– MasterAM
Jun 12 '14 at 13:32
...