大约有 44,000 项符合查询结果（耗时：0.0223秒） [XML]
When to use enumerateObjectsUsingBlock vs. for
...each invocation of the block with an autorelease pool (as of OS X 10.10 at least). This explains the performance difference compared to for in which doesn't do that.
– Pol
Dec 5 '14 at 19:31
...
JavaScript: Create and save file [duplicate]
...o save the file before creating it is not possible. But it is possible, at least in Chrome, to generate files using just JavaScript. Here is an old example of mine of creating a CSV file. The user will be prompted to download it. This, unfortunately, does not work well in other browsers, especially ...
IISExpress returns a 503 error from remote machines
...ate 4 on windows 8. This was my first come back to MS VS since studies (at least 8 years) and now I'm sure that linux rules. On django this kind of setup took me 10min of searching documentation.
turn off firewall for testing
netsh advfirewall set allprofiles state off
setup bindings in my ...
PersistentObjectException: detached entity passed to persist thrown by JPA and Hibernate
...d tricky, so it's a dirty workaround in your case. You need to remember at least that when you pass an entity object to merge, it stops being attached to the transaction and instead a new, now-attached entity is returned. This means that if anyone has the old entity object still in their possession,...
NOT IN vs NOT EXISTS
...contributed to the 10 mins, but the other option taking 4 secs explains, atleast to me that NOT EXISTS is far better or at least that IN and EXISTS are not exactly the same and always worth a check before going ahead with code.
...
Difference between “read commited” and “repeatable read”
... data.
under REPEATABLE READ the second SELECT is guaranteed to display at least the rows that were returned from the first SELECT unchanged. New rows may be added by a concurrent transaction in that one minute, but the existing rows cannot be deleted nor changed.
under SERIALIZABLE reads the second...
creating a strikethrough text?
... API or version are useful. If there is any rule in stackoverflow which at least recommed it, I will do it without problems.
– Ignacio Alorre
Aug 25 '17 at 5:53
3
...
Replace comma with newline in sed on MacOS?
...'
You need a backslash-escaped literal newline to get to sed.
In bash at least, $'' strings will replace \n with a real newline, but then you have to double the backslash that sed will see to escape the newline, e.g.
echo "a,b" | sed -e $'s/,/\\\n/g'
Note this will not work on all shells, but w...
How do you create a random string that's suitable for a session ID in PostgreSQL?
...out 1020 bits, just reading the file once from end to end would result, at least, in about 100 times more mis-read UUIDs than duplicates. Storage, network, power, and other hardware and software errors would undoubtedly be thousands of times more frequent than UUID duplication problems.
source: wi...
What's the difference between identifying and non-identifying relationships?
...or an identifying relationship.
Yes, a book can not be written without at least one author, but the author(it's foreign key) of the book is NOT IDENTIFYING the book in the books table!
You can remove the author (FK) from the book row and still can identify the book row by some other field (ISBN, I...