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What is a stack trace, and how can I use it to debug my application errors?
...32 more
Caused by: java.sql.SQLException: Violation of unique constraint MY_ENTITY_UK_1: duplicate value(s) for column(s) MY_COLUMN in statement [...]
at org.hsqldb.jdbc.Util.throwError(Unknown Source)
at org.hsqldb.jdbc.jdbcPreparedStatement.executeUpdate(Unknown Source)
at com.mchange....
Xamarin 2.0 vs Appcelerator Titanium vs PhoneGap [duplicate]
...
References and links
http://www.theregister.co.uk/Print/2013/02/25/cross_platform_abstraction/
http://kevinwhinnery.com/post/22764624253/comparing-titanium-and-phonegap
http://forums.xamarin.com/discussion/1003/your-opinion-about-several-crossplatform-frameworks#Comment_3334
http://azdevelop.azur...
How do I merge two dictionaries in a single expression in Python (taking union of dictionaries)?
...z = {**x, **y}
In Python 2, (or 3.4 or lower) write a function:
def merge_two_dicts(x, y):
z = x.copy() # start with x's keys and values
z.update(y) # modifies z with y's keys and values & returns None
return z
and now:
z = merge_two_dicts(x, y)
In Python 3.9.0a4 or greater...
How to debug Lock wait timeout exceeded on MySQL?
... query id 124164167 10.64.89.145 viget updating
DELETE FROM file WHERE file_id in ('6dbafa39-7f00-0001-51f2-412a450be5cc' )
Foreign key constraint fails for table `backoffice`.`attachment`:
,
CONSTRAINT `attachment_ibfk_2` FOREIGN KEY (`file_id`) REFERENCES `file` (`file_id`)
Trying to delete or u...
What are the most interesting equivalences arising from the Curry-Howard Isomorphism?
...ing, and reduction rules, as usual in C-H. See: en.wikipedia.org/wiki/Modal_logic and cs.cmu.edu/~fp/papers/mscs00.pdf
– RD1
Jul 30 '10 at 11:13
2
...
How does Java handle integer underflows and overflows and how would you check for it?
...int left, int right) {
if (right < 0 && right != Integer.MIN_VALUE) {
return willSubtractionOverflow(left, -right);
} else {
return (~(left ^ right) & (left ^ (left + right))) < 0;
}
}
public static boolean willSubtractionOverflow(int left, int right) {...
Secure hash and salt for PHP passwords
...This answer was written in 2008.
Since then, PHP has given us password_hash and password_verify and, since their introduction, they are the recommended password hashing & checking method.
The theory of the answer is still a good read though.
TL;DR
Don'ts
Don't limit what character...
Optimise PostgreSQL for fast testing
...elsewhere. If and only if you're doing to turn fsync off can also turn full_page_writes off, as it no longer does any good then. Beware that fsync=off and full_page_writes apply at the cluster level, so they affect all databases in your PostgreSQL instance.
For production use you can possibly use s...
Is git's semi-secret empty tree object reliable, and why is there not a symbolic name for it?
...n value").
Note: Git 2.25.1 (Feb. 2020) proposes in commit 9c8a294:
empty_tree=$(git mktree </dev/null)
# Windows:
git mktree <NUL
And adds:
As a historical note, the function now known as repo_read_object_file() was taught the empty tree in 346245a1bb ("hard-code the empty tree object...
Using Kafka as a (CQRS) Eventstore. Good idea?
...sage will be processed once and only once. 2. ) I don't like anything like _V2 in service code, so either you will backup to archive and recreate old events to their new versions (you still have the original truth), or