大约有 40,000 项符合查询结果（耗时：0.0459秒） [XML]
What is the difference between char, nchar, varchar, and nvarchar in SQL Server?
...on as illustrated below.
DECLARE @T TABLE
(
C1 VARCHAR(20) COLLATE Chinese_Traditional_Stroke_Order_100_CS_AS_KS_WS,
C2 NVARCHAR(20)COLLATE Chinese_Traditional_Stroke_Order_100_CS_AS_KS_WS
)
INSERT INTO @T
VALUES (N'中华人民共和国',N'中华人民共和国'),
(N'abc',N'abc')...
How to import CSV file data into a PostgreSQL table?
...rticle.
Solution paraphrased here:
Create your table:
CREATE TABLE zip_codes
(ZIP char(5), LATITUDE double precision, LONGITUDE double precision,
CITY varchar, STATE char(2), COUNTY varchar, ZIP_CLASS varchar);
Copy data from your CSV file to the table:
COPY zip_codes FROM '/path/to/csv/ZI...
Setting the selected value on a Django forms.ChoiceField
...e initial value when you instantiate the form:
form = MyForm(initial={'max_number': '3'})
share
|
improve this answer
|
follow
|
...
Is it better in C++ to pass by value or pass by constant reference?
...r iterators and for function objects (lambdas, classes deriving from std::*_function).
This was especially true before the existence of move semantics. The reason is simple: if you passed by value, a copy of the object had to be made and, except for very small objects, this is always more expensive...
Preserving order with LINQ
...
so because OrderBy is a stable sort, then: seq.OrderBy( _ => _.Key ) will put the elements in to exactly the same order as seq.GroupBy( _ => _.Key ).SelectMany( _ => _ ). Is that correct?
– dmg
Feb 1 '16 at 22:11
...
How to avoid 'cannot read property of undefined' errors?
...tive "in", but allows paths.
var testObject = {a: {b: {c: 'walrus'}}};
if(_.has(testObject, 'a.b.c')) {
//Safely access your walrus here
}
share
|
improve this answer
|
f...
Error handling with node.js streams
...eam module
instantiate ( or inherit from) the Transform class
implement a _transform method which takes a (chunk, encoding, callback).
The chunk is your data. Most of the time you won't need to worry about encoding if you are working in objectMode = true. The callback is called when you are done...
Unique fields that allow nulls in Django
...pty string by providing your own customized model form for Foo with a clean_bar method that turns the empty string into None:
class FooForm(forms.ModelForm):
class Meta:
model = Foo
def clean_bar(self):
return self.cleaned_data['bar'] or None
class FooAdmin(admin.ModelAdmin...
When and why will a compiler initialise memory to 0xCD, 0xDD, etc. on malloc/free/new/delete?
...oc().
0xBAADF00D Bad Food Memory allocated by LocalAlloc() with LMEM_FIXED,but
not yet written to.
0xFEEEFEEE OS fill heap memory, which was marked for usage,
but wasn't allocated by HeapAlloc() or LocalAlloc().
...
How should a model be structured in MVC? [closed]
...a mock database dependency in your model):
class Database {
protected $_conn;
public function __construct($connection) {
$this->_conn = $connection;
}
public function ExecuteObject($sql, $data) {
// stuff
}
}
abstract class Model {
protected $_db;
public fu...