大约有 30,000 项符合查询结果（耗时：0.0478秒） [XML]
What is the difference between id and class in CSS, and when should I use them? [duplicate]
Here I gave an id to the div element and it's applying the relevant CSS for it.
15 Answers
...
How to round a number to n decimal places in Java
What I would like is a method to convert a double to a string which rounds using the half-up method - i.e. if the decimal to be rounded is 5, it always rounds up to the next number. This is the standard method of rounding most people expect in most situations.
...
Return a “NULL” object if search result not found
..., you need to return a pointer, not a reference:
Attr *getAttribute(const string& attribute_name) const {
//search collection
//if found at i
return &attributes[i];
//if not found
return nullptr;
}
Otherwise, if you insist on returning by reference, then you shoul...
Why does Java have transient fields?
...ava.io.Serializable;
class NameStore implements Serializable{
private String firstName;
private transient String middleName;
private String lastName;
public NameStore (String fName, String mName, String lName){
this.firstName = fName;
this.middleName = mName;
...
MySQL select 10 random rows from 600K rows fast
...m AS r1 JOIN
(SELECT CEIL(RAND() *
(SELECT MAX(id)
FROM random)) AS id)
AS r2
WHERE r1.id >= r2.id
ORDER BY r1.id ASC
LIMIT 1
This supposes that the distribution of ids is equal, and that there can be gaps in the id list. See the ar...
@Basic(optional = false) vs @Column(nullable = false) in JPA
...and it turns out the annotation is ignored in actual usage (at least for a String field). (e.g. entityManager.persist calls).
So I went to the specification and read up about it.
Here is what the spec has to say:
http://download.oracle.com/otndocs/jcp/persistence-2.0-fr-oth-JSpec/
Basic(optiona...
Test if a variable is a list or tuple
...ometimes you need to behave differently if someone, for instance, passes a string. My preference there would be to explicitly check for str or unicode like so:
import types
isinstance(var, types.StringTypes)
N.B. Don't mistake types.StringType for types.StringTypes. The latter incorporates str ...
How to find largest objects in a SQL Server database?
...ceMB
FROM
sys.tables t
INNER JOIN
sys.indexes i ON t.object_id = i.object_id
INNER JOIN
sys.partitions p ON i.object_id = p.object_id AND i.index_id = p.index_id
INNER JOIN
sys.allocation_units a ON p.partition_id = a.container_id
WHERE
t.name NOT LIKE 'dt%' AND
i.o...
Real life example, when to use OUTER / CROSS APPLY in SQL
... FROM sys.parameters pa
WHERE pa.object_id = pr.object_id
ORDER BY pr.name) pa
ORDER BY pr.name,
pa.name
2) Calling a Table Valued Function for each row in the outer query
SELECT *
FROM sys.dm_exec_query_stats AS qs
CROSS APPLY s...
Best timestamp format for CSV/Excel?
...
For anyone using Ruby's strftime, the equivalent argument string is "%Y-%m-%d %H:%M:%S"
– madevident
Jan 27 '16 at 15:37
...