大约有 22,000 项符合查询结果（耗时：0.0372秒） [XML]
PostgreSQL “DESCRIBE TABLE”
...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 constraint in MySQL is not working
...GER `test_before_insert` BEFORE INSERT ON `Test`
FOR EACH ROW
BEGIN
IF CHAR_LENGTH( NEW.ID ) < 4 THEN
SIGNAL SQLSTATE '12345'
SET MESSAGE_TEXT := 'check constraint on Test.ID failed';
END IF;
END$$
DELIMITER ;
Prior to MySQL 5.5 you had to cause an error, e.g. ca...
How do I measure time elapsed in Java? [duplicate]
...will be used for the JAMon monitor, hence the call to thisJoinPoint.toShortString()):
public aspect MonitorAspect {
pointcut monitor() : execution(* *.ClassToMonitor.methodToMonitor(..));
Object arround() : monitor() {
Monitor monitor = MonitorFactory.start(thisJoinPoint.toShortStr...
How To Check If A Key in **kwargs Exists?
... can see, if prefix is not contained in kwargs, then the default '' (empty string) is being stored in the local prefix variable. If it is given, then its value is being used.
This is generally a compact and readable recipe for writing wrappers for any kind of function: Always just pass-through argu...
Java: when to use static methods
...atic imports. Easier, shorter.
Adding methods: you really wanted the class String to have a removeSpecialChars() instance method, but it's not there (and it shouldn't, since your project's special characters may be different from the other project's), and you can't add it (since Java is somewhat san...
How do I expand a tuple into variadic template function's arguments?
...{
typedef void (T::*F)( Args... args );
public:
Message( const std::string& name,
T& obj,
F pFunc,
Args... args );
private:
virtual void doDispatch( );
T* pObj_;
F pFunc_;
std::tr1::tuple<Args...> args_;
};
//----------------------...
NOT IN vs NOT EXISTS
...der Details] contains any NULL ProductIds is to return no results. See the extra anti semi join and row count spool to verify this that is added to the plan.
If Products.ProductID is also changed to become NULL-able the query then becomes
SELECT ProductID,
ProductName
FROM Products p
WH...
Container-fluid vs .container
...s as you change the width of your window/browser by any amount, leaving no extra empty space on the sides ever, unlike how .container does. (Hence the naming: "fluid" as opposed to "digital", "discrete", "chunked", or "quantized").
.container resizes in chunks at several certain widths. In other wo...
What is stability in sorting algorithms and why is it important?
...r if you have two input lists A,B which are identical except list B has an extra entry, the outputs for a stable sort will be identical except that B has that same extra entry. And +1 for last pgph.
– greggo
Feb 10 '13 at 1:43
...
Get the first item from an iterable that matches a condition
...for x in the_iterable if x > 3), default_value)
Note that you need an extra pair of parentheses around the generator expression in this case − they are needed whenever the generator expression isn't the only argument.
I see most answers resolutely ignore the next built-in and so I assume tha...