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JPA OneToMany not deleting child
...e JPA doesn't cater for it.
In part this is because JPA doesn't actually know if it should delete something removed from the collection. In object modeling terms, this is the difference between composition and "aggregation*.
In composition, the child entity has no existence without the parent. A c...
Python to print out status bar and percentage
...t modification: sys.stdout.write("[%-20s] %d%%" % ('='*int(20*j), 100*j)). Now the only change you need to make is to n=21 before the loop (more likely n=len(iterable)), then enumerate over the iterable object. I recommended this edit but it was rejected; apparently functionality "deviates from the ...
Generating v5 UUID. What is name and namespace?
...ducible UUID for each namespace using "uuid -v5 $ROOTUUID $NAMESPACENAME". Now you can create unique UUIDs for keys within a namespace using "uuid -v5 $NAMESPACEUUID $KEY". These UUIDs can be thrown into a single key-value store with high probability of avoiding collision. This process can be repea...
Difference between socket and websocket?
...kets in their implementation. Websockets are based on a standard protocol (now in final call, but not yet final) that defines a connection "handshake" and message "frame." The two sides go through the handshake procedure to mutually accept a connection and then use the standard message format ("fram...
Display current time in 12 hour format with AM/PM
...
Outmoded now. These formatting codes are now supplanted by the formatting codes of the DateTimeFormatter class, per JSR 310.
– Basil Bourque
Sep 3 '19 at 1:45
...
Python nonlocal statement
...: 2
# outer: 1
# global: 0
To this, using nonlocal, where inner()'s x is now also outer()'s x:
x = 0
def outer():
x = 1
def inner():
nonlocal x
x = 2
print("inner:", x)
inner()
print("outer:", x)
outer()
print("global:", x)
# inner: 2
# outer: 2
# global...
How to inherit from a class in javascript?
...
I have changed how I do this now, I try to avoid using constructor functions and their prototype property, but my old answer from 2010 is still at the bottom. I now prefer Object.create(). Object.create is available in all modern browsers.
I should not...
Convert NSArray to NSString in Objective-C
...rWords = [myString componentsSeparatedByString:@" "];
// yourWords is now: [@"This", @"is", @"a", @"test", @"string"]
if you need to split on a set of several different characters, use NSString’s componentsSeparatedByCharactersInSet:
NSString *yourString = @"Foo-bar/iOS-Blog";
NSArray *you...
How to concatenate two strings in C++?
...td::string greet = s + " World"; //concatenation easy!
Easy, isn't it?
Now if you need char const * for some reason, such as when you want to pass to some function, then you can do this:
some_c_api(s.c_str(), s.size());
assuming this function is declared as:
some_c_api(char const *input, si...
How do I parse an ISO 8601-formatted date?
... only) in ambiguous cases. So ONLY use it if you need to parse input of unknown format and are okay to tolerate occasional misreads.
– ivan_pozdeev
Apr 23 '15 at 23:34
2
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