大约有 20,000 项符合查询结果（耗时：0.0331秒） [XML]
Why doesn't the example compile, aka how does (co-, contra-, and in-) variance work?
...ranslating their example to use your construct:
val x = new Slot[String]("test") // Make a slot
val y: Slot[Any] = x // Ok, 'cause String is a subtype of Any
y.set(new Rational(1, 2)) // Works, but now x.get() will blow up
If you feel I'm not understanding your question (a dis...
What are the best PHP input sanitizing functions?
...scape_string. Also the enclosing quotes, but everybody does it, and if you test what you do, you end up with a SQL syntax error with this omission. The real dangerous part is handled with mysql_real_escape_string.
– Savageman
Jun 27 '10 at 14:27
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What is the most efficient/elegant way to parse a flat table into a tree?
...BLE AS m JOIN MyTree AS t ON m.ParentId = t.Id
)
SELECT * FROM MyTree;
I tested recursive queries in MySQL 8.0 in my presentation Recursive Query Throwdown in 2017.
Below is my original answer from 2008:
There are several ways to store tree-structured data in a relational database. What you s...
Difference between git checkout --track origin/branch and git checkout -b branch origin/branch
...
@Green The test you do is with origin/new-branch instead of origin/branch. Are you aware of that?
– Robert Siemer
Apr 13 '19 at 22:02
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Rebasing and what does one mean by rebasing pushed commits
...ID (in this case, a, b, c, and d). You'll notice that d is currently the latest commit (or HEAD) of the master branch.
Here, we have two branches: master and my-branch. You can see that master and my-branch both contain commits a and b, but then they start to diverge: master contains c and d, whil...
What's the difference between a catalog and a schema in a relational database?
...per host computer (or virtual OS). Multiple clusters is commonly done, for testing and deploying new versions of Postgres (ex: 9.0, 9.1, 9.2, 9.3, 9.4, 9.5).
If you did have multiple clusters, imagine the diagram above duplicated.
Different port numbers allow the multiple clusters to live side-by...
How to remove/delete a large file from commit history in Git repository?
...han 100M my-repo.git
Any files over 100MB in size (that aren't in your latest commit) will be removed from your Git repository's history. You can then use git gc to clean away the dead data:
$ git gc --prune=now --aggressive
The BFG is typically at least 10-50x faster than running git-filter-br...
How to parse an RSS feed using JavaScript?
...'#rss-viewer')[0].innerHTML = aDocumentFragmentOfAllEntries.innerHTML;
Test Data
Using this question's feed, which as of this writing gives:
<?xml version="1.0" encoding="utf-8"?>
<feed xmlns="http://www.w3.org/2005/Atom" xmlns:creativeCommons="http://backend.userland.com/creativeComm...
Convert JavaScript string in dot notation into an object reference
...
@Mr.B. the latest version of Lodash has a third, optional, argument for defaultValue. The _.get() method returns the default value if _.get() resolves to undefined, so set it to whatever you want and watch for the value you set.
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How important is the order of columns in indexes?
...tioned in one Answer.
So, what order should be used?
Start with column(s) tested with =, in any order.
Then tack on one range column.
For example, the very-low selectivity column must come first in this:
WHERE deleted = 0 AND the_datetime > NOW() - INTERVAL 7 DAY
INDEX(deleted, the_datetime)
...