大约有 43,000 项符合查询结果（耗时：0.0273秒） [XML]
Likelihood of collision using most significant bits of a UUID in Java
...ostSignificantBits() how likely is it to get a collision. It cuts off the least significant bits, so there is a possibility that you run into a collision, right?
...
PostgreSQL - max number of parameters in “IN” clause?
...y an answer to the present question, however it might help others too.
At least I can tell there is a technical limit of 32767 values (=Short.MAX_VALUE) passable to the PostgreSQL backend, using Posgresql's JDBC driver 9.1.
This is a test of "delete from x where id in (... 100k values...)" with th...
Foreign key constraints: When to use ON UPDATE and ON DELETE
... do not have advanced constraints like you would have in postgreSQL but at least the foreign key constraints are quite advanced.
We'll take an example, a company table with a user table containing people from theses company
CREATE TABLE COMPANY (
company_id INT NOT NULL,
company_name VAR...
MongoDB: Combine data from multiple collections into one..how?
...ollection('freelancers').aggregate( // 1. Use any collection containing at least one document.
[
{ $limit: 1 }, // 2. Keep only one document of the collection.
{ $project: { _id: '$$REMOVE' } }, // 3. Remove everything from the document.
// 4. Lookup collections to union together.
...
How to determine if a record is just created or updated in after_save
...
This might has changed. At least in Rails 4, the after_save callback runs after the after_create or after_update callback (see guides.rubyonrails.org/active_record_callbacks.html).
– Mark
Jul 16 '14 at 14:16
...
How to randomly select rows in SQL?
...
should have at least replaced 1 with 5 :)
– roman m
Feb 24 '09 at 6:40
add a comment
|
...
unique object identifier in javascript
...
neither of i would recomend to do this also, at least not for every object, you can do the same just with the objects you handle. unfortunately most of the time we have to use external javascript libraries, and unfortunately not every one of them are well programed so avoi...
Is there any particular difference between intval and casting to int - `(int) X`?
...needing no conversion, regardless of the base argument (as of PHP 5.3.5 at least). This behavior isn't the most obvious, as noted in the comments on the PHP doc page and shamelessly reiterated here:
$test_int = 12;
$test_string = "12";
$test_float = 12.8;
echo (int) $test_int; // 12
ec...
Is there a 'box-shadow-color' property?
...ox-shadow: 1px 2px 3px;
color: #a00;
Support
Safari 6+
Chrome 20+ (at least)
Firefox 13+ (at least)
IE9+ (IE8 doesn't support box-shadow at all)
Demo
div {
box-shadow: 0 0 50px;
transition: 0.3s color;
}
.green {
color: green;
}
.red {
color: red;
}
div:hover {...
Regex expressions in Java, \\s vs. \\s+
...re times
X+ X, one or more times
X{n} X, exactly n times
X{n,} X, at least n times
X{n,m} X, at least n but not more than m times
Reluctant quantifiers
X?? X, once or not at all
X*? X, zero or more times
X+? X, one or more times
X{n}? X, exactly n times
X{n,}? X, at least n times
X{n,m}? ...