大约有 40,000 项符合查询结果（耗时：0.0663秒） [XML]
Update multiple rows in same query using PostgreSQL
...
This is wrong... You will update all rows, even if it is not '123' nor '345'. You should use WHERE column_b IN ('123','456')...
– MatheusOl
Sep 14 '13 at 3:54
...
Query to list all stored procedures
What query can return the names of all the stored procedures in a SQL Server database
23 Answers
...
How do I correctly clone a JavaScript object?
... if you know its name, but I don't know of any way to discover it automatically.
Yet another snag in the quest for an elegant solution is the problem of setting up the prototype inheritance correctly. If your source object's prototype is Object, then simply creating a new general object with {} wil...
Installing Java 7 on Ubuntu
to install java I have always used the classic way from the terminal.
I would like to install java manually.
I placed the folder of the JDK on the desk and I set environment variables (PATH, CLASSPATH and JAVA_HOME).
From the terminal, if I type java -version I get printed
...
Image Greyscale with CSS & re-color on mouse-over?
...rayscale(100%);
/* Chrome 19+ & Safari 6+ */
-webkit-transition: all .6s ease;
/* Fade to color for Chrome and Safari */
-webkit-backface-visibility: hidden;
/* Fix for transition flickering */
}
img.grayscale:hover {
filter: none;
-webkit-filter: grayscale(0%);
}
sv...
Saving a Numpy array as an image
... Remember to scale the values to the right range for PNG, usually 0..255. The value ranges in neural networks are frequently 0..1 or -1..1.
– Tomáš Gavenčiak
Mar 31 '18 at 18:49
...
How to use Single TextWatcher for multiple EditTexts?
...idgets in my view layout. Is there a way to use a single TextWatcher for all three EditTexts ?
13 Answers
...
Coding Practices which enable the compiler/optimizer to make a faster program
...act.
Expect to be disappointed and to have to work very hard indeed for small performance improvements. Modern compilers for mature languages such as Fortran and C are very, very good. If you read an account of a 'trick' to get better performance out of code, bear in mind that the compiler writer...
Why doesn't django's model.save() call full_clean()?
...t curious if anyone knows if there's good reason why django's orm doesn't call 'full_clean' on a model unless it is being saved as part of a model form.
...
mongo group query how to keep fields
...are accumulated/funneled/reduced) doesn't make so much sense even theoretically. However, sorting before hand is actually inefficient compared to sorting each group within themselves since sorting algorithms are more complex than O(n). I wish there would be better ways in MongoDB.
...