大约有 45,000 项符合查询结果（耗时：0.0331秒） [XML]
Is there a way to change the environment variables of another process in Unix?
...ocesses.
Suppose that you write your own shared library which implements 'char *getenv'. Then, you set up 'LD_PRELOAD' or 'LD_LIBRARY_PATH' env. vars so that both your processes are run with your shared library preloaded.
This way, you will essentially have a control over the code of the 'getenv' ...
Get table column names in MySQL?
...DESCRIBE my_table;
Or in newer versions you can use INFORMATION_SCHEMA:
SELECT COLUMN_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_SCHEMA = 'my_database' AND TABLE_NAME = 'my_table';
Or you can use SHOW COLUMNS:
SHOW COLUMNS FROM my_table;
...
Create unique constraint with null columns
...houtMenu row first and then link it to a menu if necessary. It also makes selecting all the favorites in one query very difficult: I'd have to do something weird like select all the menu links first, and then select all the Favorites whose IDs don't exist within the first query. I'm not sure if I ...
ElasticSearch, Sphinx, Lucene, Solr, Xapian. Which fits for which usage? [closed]
... SET NAMES utf8
# query before fetching rows to index
sql_query = SELECT *, id AS pid, CRC32(safetag) as safetag_crc32 FROM hb_posts
sql_attr_uint = pid
# pid (as 'sql_attr_uint') is necessary for sphinx
# this field must be unique
# that is why I like sphinx
# you ...
Memcached下一站：HandlerSocket！ - 更多技术 - 清泛网 - 专注C/C++及内核技术
...没有实际运行SQL，所以Binlog记录的是Row格式。
SQL原型：SELECT id, a, b FROM test.t WHERE id = 1 LIMIT 1
shell> telnet localhost 9999
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
P 1 test t PRIMARY id,a,b
0 1
1 = ...
Convert to absolute value in Objective-C
...+ programs too.)
(Alas, there is no habs(short) function. Or scabs(signed char) for that matter...)
Apple's and GNU's Objective-C headers also include an ABS() macro which is type-agnostic. I don't recommend using ABS() however as it is not guaranteed to be side-effect-safe. For instance, ABS(a+...
how to customize `show processlist` in mysql?
...
Newer versions of SQL support the process list in information_schema:
SELECT * FROM INFORMATION_SCHEMA.PROCESSLIST
You can ORDER BY in any way you like.
The INFORMATION_SCHEMA.PROCESSLIST table was added in MySQL 5.1.7. You can find out which version you're using with:
SELECT VERSION()
...
conditional unique constraint
... CheckActiveCount(
@Id INT
) RETURNS INT AS BEGIN
DECLARE @ret INT;
SELECT @ret = COUNT(*) FROM CheckConstraint WHERE Id = @Id AND RecordStatus = 1;
RETURN @ret;
END;
GO
ALTER TABLE CheckConstraint
ADD CONSTRAINT CheckActiveCountConstraint CHECK (NOT (dbo.CheckActiveCount(Id) > 1 AND...
What does the “__block” keyword mean?
...c NSInteger CounterStatic;
{
NSInteger localCounter = 42;
__block char localCharacter;
void (^aBlock)(void) = ^(void) {
++CounterGlobal;
++CounterStatic;
CounterGlobal = localCounter; // localCounter fixed at block creation
localCharacter = 'a'; // sets ...
What is the difference between decodeURIComponent and decodeURI?
...arators are encoded also because they are regarded as text and not special characters.
Now back to the difference between the decode functions, each function decodes strings generated by its corresponding encode counterpart taking care of the semantics of the special characters and their handling.
...