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JPA EntityManager: Why use persist() over merge()?
...e example will help.
MyEntity e = new MyEntity();
// scenario 1
// tran starts
em.persist(e);
e.setSomeField(someValue);
// tran ends, and the row for someField is updated in the database
// scenario 2
// tran starts
e = new MyEntity();
em.merge(e);
e.setSomeField(anotherValue);
// tran ends ...
Use of Application.DoEvents()
... could click the same menu item or button that causes the same loop to get started. Now you have two nested loops executing DoEvents(), the previous loop is suspended and the new loop is starting from scratch. That could work, but boy the odds are slim. Especially when the nested loop ends and th...
Should I use single or double colon notation for pseudo-elements?
...f single colons will not be allowed for new pseudo-elements, shouldn't you start using double colons to get in the habit?
– andrewtweber
Jan 4 '16 at 19:02
...
What do I need to read to understand how git works? [closed]
...
Git From the Bottom Up is the starting point for understanding the architecture. Linus's talk complements it well.
– Paul
Nov 4 '08 at 13:50
...
How do I write outputs to the Log in Android?
...b.ardakaplan:RDALogger:1.0.0'
}
For initializing library, you should start like this (in Application.class or before first use)
RDALogger.start("TAG NAME").enableLogging(true);
And than you can log whatever you want;
RDALogger.info("info");
RDALogger.debug("debug");
RDALogger.v...
How to reset postgres' primary key sequence when it falls out of sync?
...sort to the ALTER SEQUENCE syntax i.e.
ALTER SEQUENCE table_name_id_seq RESTART WITH 1;
ALTER SEQUENCE table_name_id_seq RESTART; -- 8.4 or higher
But ALTER SEQUENCE is of limited use because the sequence name and restart value cannot be expressions.
It seems the best all-purpose solution is to ...
Web-scraping JavaScript page with Python
...simple example:
class MySpider(scrapy.Spider):
name = "jsscraper"
start_urls = ["http://quotes.toscrape.com/js/"]
def start_requests(self):
for url in self.start_urls:
yield SplashRequest(
url=url, callback=self.parse, endpoint='render.html'
)
d...
Try catch statements in C
...intf("Exception happened here\n");
} else {
// Normal code execution starts here
Test();
}
}
void Test() {
// Rough equivalent of `throw`
longjmp(s_jumpBuffer, 42);
}
This website has a nice tutorial on how to simulate exceptions with setjmp and longjmp
http://www.di.unipi.it/~...
Python dictionary: are keys() and values() always the same order?
...
Yes. Starting with CPython 3.6, dictionaries return items in the order you inserted them.
Ignore the part that says this is an implementation detail. This behaviour is guaranteed in CPython 3.6 and is required for all other Pyth...
Spring @Autowired usage
...peated all over. To me this seems to have the potential for errors.
I've started using auto-wiring almost exclusively at work because we depend so much on Spring integration anyway that the dependency issue is moot. I worked on a Spring MVC project that used auto-wiring extensively and was a littl...