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Swapping column values in MySQL
...work:
UPDATE swap_test s1, swap_test s2 SET s1.x=s1.y, s1.y=s2.x WHERE s1.id=s2.id;
Essentially, the 1st table is the one getting updated and the 2nd one is used to pull the old data from.
Note that this approach requires a primary key to be present.
This is my test schema:
CREATE TABLE `swap_t...
Aligning a float:left div to center?
...
you may need to add vertical-align:middle while using display:inline-block.
– ibsenv
May 24 '15 at 10:59
...
Node / Express: EADDRINUSE, Address already in use - Kill server
... currently running stacks here and there) it makes no sense to put that inside the exit event...
On crash, do process.on('uncaughtException', ..) and on kill do process.on('SIGTERM', ..)
That being said, SIGTERM (default kill signal) lets the app clean up, while SIGKILL (immediate termination) won...
Jackson - Deserialize using generic class
... the class as a parameter during runtime. Like this public <T> void deSerialize(Class<T> clazz { ObjectMapper mapper = new ObjectMapper(); mapper.readValue(jsonString, new TypeReference<Json<T>>() {}); }
– gnjago
...
Show or hide element in React
... around with React.js for the first time and cannot find a way to show or hide something on a page via click event. I am not loading any other library to the page, so I am looking for some native way using the React library. This is what I have so far. I would like to show the results div when th...
Rails 4 - Strong Parameters - Nested Objects
... the other hand if you want nested of multiple objects then you wrap it inside a hash… like this
params.require(:foo).permit(:bar, {:baz => [:x, :y]})
Rails actually have pretty good documentation on this: http://api.rubyonrails.org/classes/ActionController/Parameters.html#method-i-permit
...
JavaScript: Upload file
...e fetch optionally with await-try-catch
let photo = document.getElementById("image-file").files[0];
let formData = new FormData();
formData.append("photo", photo);
fetch('/upload/image', {method: "POST", body: formData});
async function SavePhoto(inp)
{
let user = { name:'john', age:...
Is it possible to have two partial classes in different assemblies represent the same class?
...view of the different flavours of MVC, MVP and whatnot: you'll find design ideas aplenty. I suppose you could also use Dependency Injection to tell the UI what kind of controls are viable for individual entities and attributes.
Your aim of separating concerns is great; but partial classes were int...
What is the most efficient way to create HTML elements using jQuery?
...hnique is the fastest. I speculate this is because jQuery doesn't have to identify it as an element and create the element itself.
You should really run benchmarks with different Javascript engines and weigh your audience with the results. Make a decision from there.
...
Find size of object instance in bytes in c#
...if you're working with serializable objects.
class Program
{
static void Main(string[] args)
{
A parent;
parent = new A(1, "Mike");
parent.AddChild("Greg");
parent.AddChild("Peter");
parent.AddChild("Bobby");
System.Runtime.Serialization.Form...