大约有 47,000 项符合查询结果（耗时：0.0527秒） [XML]
What's the $unwind operator in MongoDB?
...oDB employs an "NoSQL" approach to data storage, so perish the thoughts of selects, joins, etc. from your mind. The way that it stores your data is in the form of documents and collections, which allows for a dynamic means of adding and obtaining the data from your storage locations.
That being sai...
How to change the CHARACTER SET (and COLLATION) throughout a database?
...re schema to utf8. Hope this helps!
-- Change DATABASE Default Collation
SELECT DISTINCT concat('ALTER DATABASE `', TABLE_SCHEMA, '` CHARACTER SET utf8 COLLATE utf8_unicode_ci;')
from information_schema.tables
where TABLE_SCHEMA like 'database_name';
-- Change TABLE Collation / Char Set
SELECT...
Windows 7 SDK installation failure
...or modification.
Condition 1: If the Visual C++ Compilers checkbox is selected when the
Windows SDK 7.1 is installed, repaired, or modified after Visual
Studio 2010 SP1 has been installed, the error may be encountered and
some selected components may not be installed.
Workaround: Cl...
MySQL remove all whitespaces from the entire column
...
Working Query:
SELECT replace(col_name , ' ','') FROM table_name;
While this doesn't :
SELECT trim(col_name) FROM table_name;
share
|
im...
SSL Connection / Connection Reset with IISExpress
...rtificate:
On Start, type -> mmc.exe
File -> Add/Remove Snap-in...
Select Certificates -> Add> -> Computer account -> Local computer
Check under Certificates > Personal > Certificates
Make sure the localhost certificate that exist has a friendly name "IIS Express Developmen...
Find a Pull Request on Github where a commit was originally created
...can just go to github and enter the SHA into the search bar, make sure you select the "Issues" link on the left.
UPDATED 13 July 2017
Via the Github UI there is a now a really easy way to do this. If you are looking at a commit in the list of commits in a branch in the UI, click on the link to the...
How to implement custom JsonConverter in JSON.NET to deserialize a List of base class objects?
...o match a divierd class based on the class given to the serilaizer
/// Selected class will be the first class to match all properties in the json object.
/// </summary>
public class KnownTypeConverter : JsonConverter
{
public override bool CanConvert(Type objectType)
...
Get lengths of a list in a jinja2 template
... Thanks @AlexMartelli. In addition we could use inline syntax like {{ form.select_field(size=5 if form.select_field.choices|count > 5 else form.select_field.choices|count) }}
– Filipe Bezerra de Sousa
Jun 28 at 23:52
...
Android: allow portrait and landscape for tablets, but force portrait on phone?
...h their bools.xml files.
values-sw600dp
First of all, from the Project tab select the Project (rather than Android) filter in the navigator.
Then right click the app/src/main/res directory. Choose New > Android Resource Directory.
Select Smallest Screen Width, and then press the >> button....
python pandas remove duplicate columns
...,False,True].
Pandas allows one to index using boolean values whereby it selects only the True values. Since we want to keep the unduplicated columns, we need the above boolean array to be flipped (ie [True, True, False] = ~[False,False,True])
Finally, df.loc[:,[True,True,False]] selects only the...