大约有 24,000 项符合查询结果（耗时：0.0491秒） [XML]
Can I have multiple primary keys in a single table?
...,'lax'),('mammal','whale'),
('bird','ostrich');
SELECT * FROM animals ORDER BY grp,id;
Which returns:
+--------+----+---------+
| grp | id | name |
+--------+----+---------+
| fish | 1 | lax |
| mammal | 1 | dog |
| mammal | 2 | cat |
| mammal | 3 | whale |
| bird ...
What is the difference between JOIN and JOIN FETCH when using JPA and Hibernate
...Worth mention that fetch has to be used if (using our example) you want to order by some Department attribute. Otherwise, (valid at least for PG) you might get ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list
– long
Apr 21 at 14:08
...
How to permanently set $PATH on Linux/Unix? [closed]
...directories like /usr/local/something/bin to PATH variable or defining JAVA_HOME. Used by PAM and SystemD.
/etc/environment.d/*.conf List of unique assignments, allows references. Perfect for adding system-wide directories like /usr/local/something/bin to PATH variable or defining JAVA_HOME. The co...
Using an if statement to check if a div is empty
...If a container has a very long HTML content?
– techie_28
Jun 17 '16 at 10:07
add a comment
|
...
Delete element in a slice
...
There are two options:
A: You care about retaining array order:
a = append(a[:i], a[i+1:]...)
// or
a = a[:i+copy(a[i:], a[i+1:])]
B: You don't care about retaining order (this is probably faster):
a[i] = a[len(a)-1] // Replace it with the last one. CAREFUL only works if you ha...
Is it Linq or Lambda?
...
This is LINQ (using query syntax):
var _Results = from item in _List
where item.Value == 1
select item;
This is also LINQ (using method syntax):
var _Results = _List.Where(x => x.Value == 1);
It's interesting to note that bo...
What are the performance characteristics of sqlite with very large database files? [closed]
... Another option is to keep the indexes, but pre-sort the data in index-order before you insert it.
– Steven Kryskalla
Feb 19 '14 at 23:42
1
...
Is the pImpl idiom really used in practice?
...hose benefits come at a cost: an extra level of indirection is required in order to access the implementation methods.
share
|
improve this answer
|
follow
|
...
iOS 7 TextKit - How to insert images inline with text?
...the following link for more details on customising the NSTextAttachment in order to resize the image.
http://ossh.com.au/design-and-technology/software-development/implementing-rich-text-with-images-on-os-x-and-ios/
In my example I resize the image to fit the width, in your case you may want to res...
What are major differences between C# and Java?
... visibility in Java which takes account of namespace (and inheritance)
The order of initialization in Java and C# is subtly different (C# executes variable initializers before the chained call to the base type's constructor)
Java doesn't have properties as part of the language; they're a convention ...