大约有 41,000 项符合查询结果（耗时：0.0645秒） [XML]
Getting and removing the first character of a string
...cters:
x <- 'hello stackoverflow'
substring(x, 2, nchar(x))
Idea is select all characters starting from 2 to number of characters in x. This is important when you have unequal number of characters in word or phrase.
Selecting the first letter is trivial as previous answers:
substring(x,1,1...
Map Tiling Algorithm
... this algorithm is to use a pre-processing step to find all edges and then select the correct smoothing tile according to the shape of the edge.
The first step would be to find all edges. In the example below the edge tiles marked with an X are all green tiles with a tan tile as one or more of thei...
How to map a composite key with JPA and Hibernate?
... way you write queries (making them more or less verbose):
with IdClass
select t.levelStation from Time t
with EmbeddedId
select t.timePK.levelStation from Time t
References
JPA 1.0 specification
Section 2.1.4 "Primary Keys and Entity Identity"
Section 9.1.14 "EmbeddedId Annotation"
Sect...
Why java classes do not inherit annotations from implemented interfaces?
...nterface and I would like to annotate the interface methods so Guice could select the right methods. Even if the annotation type is annotated with Inherited annotation implementing class doesn't inherit the annotation as stated in Inherited's java doc:
...
What's the difference between session.persist() and session.save() in Hibernate?
...st(entity);
session.getTransaction().commit();
session.close();
Result:
select nextval ('hibernate_sequence') // This is for vehicle Id generated : 36
insert into Employee_Vehicle ( Vehicle_Name, Vehicle_Id) values ( Honda, 36)
Note the result is same when you get an already persisted object an...
Image resizing client-side with JavaScript before upload to the server
...ed in a script tag)
You can use it as follows:
<input type="file" id="select">
<img id="preview">
<script>
document.getElementById('select').onchange = function(evt) {
ImageTools.resize(this.files[0], {
width: 320, // maximum width
height: 240 // maximum heigh...
How to navigate through the source code by parts in CamelCase (instead of whole words)?
...g and disabling the setting called "Honor "CamelHumps" words settings when selecting on double click".
– Paul Lammertsma
Jan 22 '15 at 13:14
9
...
Rails where condition using NOT NIL
..., so you really should just use the joins predicate:
Foo.joins(:bar)
Select * from Foo Inner Join Bars ...
But, for the record, if you want a "NOT NULL" condition simply use the not predicate:
Foo.includes(:bar).where.not(bars: {id: nil})
Select * from Foo Left Outer Join Bars on .. WHERE ...
“On-line” (iterator) algorithms for estimating statistical median, mode, skewness, kurtosis?
...oints you have, in theory you only have to partially sort, e.g. by using a selection algorithm. However, that doesn't help too much with billions of values. I would suggest using frequency counts, see the next section.
Median and Mode with Frequency Counts
If it is integers, I would count
frequenc...
Is there a use-case for singletons with database access in PHP?
...all one needs to maintain multiple database connections, multiple database selections, multiple database queries, multiple result sets in a given singleton is just keeping them in variables/arrays in the singleton as long as they are needed. This can be as simple as keeping them in arrays, though yo...