大约有 41,000 项符合查询结果（耗时：0.0454秒） [XML]
JPA getSingleResult() or null
... doesn't exist or update it if it does. To enable this, I have to findByIdAndForeignKey , if it returned null insert if not then update. The problem is how do I check if it exists? So I tried getSingleResult . But it throws an exception if the
...
MySQL: How to copy rows, but change a few fields?
... do it without having to specify the column names?
– Andrew
May 6 '10 at 18:00
4
Not that I'm awa...
Turning Sonar off for certain code
...uppressFBWarnings (added to avoid clashes with java.lang.SuppressWarnings) and also ignores it.
– Marcel Stör
Jul 17 '13 at 6:39
...
Check difference in seconds between two times
...
Assuming dateTime1 and dateTime2 are DateTime values:
var diffInSeconds = (dateTime1 - dateTime2).TotalSeconds;
In your case, you 'd use DateTime.Now as one of the values and the time in the list as the other. Be careful of the order, as the...
Ruby on Rails generates model field:type - what are the options for field:type?
I'm trying to generate a new model and forget the syntax for referencing another model's ID. I'd look it up myself, but I haven't figured out, among all my Ruby on Rails documentation links, how to find the definitive source.
...
How to convert a char to a String?
I have a char and I need a String . How do I convert from one to the other?
12 Answers
...
Responsive css background images
I have a website (g-floors.eu) and I want to make the background (in css I have defined a bg-image for the content) also responsive. Unfortunately I really don't have any idea on how to do this except for one thing that I can think of but it's quite a workaround. Creating multiple images and then us...
How to set default values in Rails?
...ove the default"
end
end
Because ActiveRecord autodiscovers your table and column properties, this will cause the same default to be set in any model using it in any standard Rails app.
However, if you only want default values set in specific cases -- say, it's an inherited model that shares a ...
is vs typeof
...
This should answer that question, and then some.
The second line, if (obj.GetType() == typeof(ClassA)) {}, is faster, for those that don't want to read the article.
(Be aware that they don't do the same thing)
...
Correct use of flush() in JPA/Hibernate
...formation about the flush() method, but I'm not quite clear when to use it and how to use it correctly. From what I read, my understanding is that the contents of the persistence context will be synchronized with the database, i. e. issuing outstanding statements or refreshing entity data.
...