大约有 40,000 项符合查询结果（耗时：0.0398秒） [XML]
PostgreSQL “DESCRIBE TABLE”
... 'table' or \ds 'sequence' and so on)
The SQL standard way, as shown here:
select column_name, data_type, character_maximum_length, column_default, is_nullable
from INFORMATION_SCHEMA.COLUMNS where table_name = '<name of table>';
It's supported by many db engines.
...
Check if a string contains a number
...n, like this
>>> def hasNumbers(inputString):
... return any(char.isdigit() for char in inputString)
...
>>> hasNumbers("I own 1 dog")
True
>>> hasNumbers("I own no dog")
False
Alternatively you can use a Regular Expression, like this
>>> import re
>&g...
Int to Char in C#
What is the best way to convert an Int value to the corresponding Char in Utf16, given that the Int is in the range of valid values?
...
How do you print out a stack trace to the console/log in Cocoa?
...#import <UIKit/UIKit.h>
#import "AppDelegate.h"
int main(int argc, char *argv[])
{
@autoreleasepool {
int retval;
@try{
retval = UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
}
@catch (NSException *exception)
...
How to check if a char is equal to an empty space?
...
if (c == ' ')
char is a primitive data type, so it can be compared with ==.
Also, by using double quotes you create String constant (" "), while with single quotes it's a char constant (' ').
...
字符串指针变量与字符数组的区别 - C/C++ - 清泛网 - 专注C/C++及内核技术
... 设有定义字符型指针变量与字符数组的语句如下： char *pc ,str[100]; 则系统...使用字符串指针变量与字符数组的区别
（1）分配内存
设有定义字符型指针变量与字符数组的语句如下：
char *pc ,str[100];
则系...
Multiple INSERT statements vs. single INSERT with multiple VALUES
...t
One place where this information is leveraged is shown by @Lieven here
SELECT *
FROM (VALUES ('Lieven1', 1),
('Lieven2', 2),
('Lieven3', 3))Test (name, ID)
ORDER BY name, 1/ (ID - ID)
Because at compile time it can determine that the Name column has no duplicates it...
See all breakpoints in Visual Studio 2010+
...
In Visual Studio 2017, Ctrl+D duplicates the current selection and Ctrl+B adds a new breakpoint at the current line. Ctrl+F9 does nothing.
– Malcolm
May 7 '19 at 16:16
...
How can I pass a member function where a free function is expected?
...n<void(int, int)> fun)
{
fun(1, 1);
}
int main (int argc, const char * argv[])
{
...
aClass a;
auto fp = std::bind(&aClass::test, a, _1, _2);
function1(fp);
return 0;
}
share
|
...
How to select a single field for all documents in a MongoDB collection?
...nt such as:
db.student.find({}, {roll:1, _id:0})
The above statement will select all documents in the students collection, and the returned document will return only the roll field (and exclude the _id).
If we don't mention _id:0 the fields returned will be roll and _id. The '_id' field is always d...