大约有 6,884 项符合查询结果（耗时：0.0132秒） [XML]
What is the difference between Views and Materialized Views in Oracle?
...t statement used by the view joins many tables, or uses joins based on non-indexed columns, the view could perform poorly.
Materialized views
They are similar to regular views, in that they are a logical view of your data (based on a select statement), however, the underlying query result set has ...
Add new methods to a resource controller in Laravel
...nds \Illuminate\Routing\Router {
protected $resourceDefaults = array('index', 'create', 'store', 'show', 'edit', 'update', 'destroy', 'delete');
/**
* Add the show method for a resourceful route.
*
* @param string $name
* @param string $base
* @param string $...
SQL Server: What is the difference between CROSS JOIN and FULL OUTER JOIN?
... often faster when there are few matches between the two tables, as use of indexes means it doesn't bother reading all the rows on one of the tables. a full outer join must always read all rows in both tables (or the relevant indexes). In the case where indexes are not enough, or an underlying heap ...
How to get the separate digits of an int number?
...you would like to maintain the order of the digits from least significant (index[0]) to most significant (index[n]), the following updated getDigits() is what you need:
/**
* split an integer into its individual digits
* NOTE: digits order is maintained - i.e. Least significant digit is at index[...
Unique constraint that allows empty values in MySQL
...
Yes, you can do this. See the MySQL reference (version 5.5).
A UNIQUE index creates a constraint such that all values in the index must be distinct. An error occurs if you try to add a new row with a key value that matches an existing row. For all engines, a UNIQUE index allows multiple NULL v...
Select row with most recent date per user
...posted by Justin, may be more optimal. The accepted answer uses a backward index scan on the primary key of the table, followed by a limit, followed by a sequence scan of the table. Therefore, the accepted answer can be greatly optimized with an additional index. This query could be optimized by an ...
Python list subtraction operation
...ting and using bisect:
ys = sorted(y)
def bisect_contains(seq, item):
index = bisect.bisect(seq, item)
return index < len(seq) and seq[index] == item
[item for item in x if bisect_contains(ys, item)]
If your items are neither hashable nor comparable, then you're stuck with the quadra...
How do I pass command line arguments to a Node.js program?
...ine arguments.
// print process.argv
process.argv.forEach(function (val, index, array) {
console.log(index + ': ' + val);
});
This will generate:
$ node process-2.js one two=three four
0: node
1: /Users/mjr/work/node/process-2.js
2: one
3: two=three
4: four
...
Dictionary returning a default value if the key does not exist [duplicate]
... DictionaryWithDefault object is upcast to a plain Dictionary, calling the indexer will use the base Dictionary implementation (throwing an exception if missing) rather than the subclass's implementation.
share
|
...
Why does a RegExp with global flag give wrong results?
...
A RegExp object with the g flag keeps track of the lastIndex where a match occurred, so on subsequent matches it will start from the last used index, instead of 0. Take a look:
var query = 'Foo B';
var re = new RegExp(query, 'gi');
var result = [];
result.push(re.test('Foo Ba...