大约有 40,000 项符合查询结果（耗时：0.0340秒） [XML]
How do I sort an NSMutableArray with custom objects in it?
...sortedArray = [drinkDetails sortedArrayUsingComparator:^NSComparisonResult(id a, id b) {
NSDate *first = [(Person*)a birthDate];
NSDate *second = [(Person*)b birthDate];
return [first compare:second];
}];
Performance
The -compare: and block-based methods will be quite a bit faster, in...
Ways to save enums in database
...ack |
This way, when you want to change your cards to use Kissing Kings New Deck Order you can change it for display purposes without throwing away all your data:
| Suit | SuitID | Rank | Color | CardOrder |
|------------|--------------|---------------|--------|-----------|...
git: fatal: Could not read from remote repository
... @user61629: I know I'm late to the party, but you should consider using private/public key pairs instead of passwords.
– code_dredd
Apr 22 '16 at 22:06
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MongoDB and “joins” [duplicate]
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As of Mongo 3.2 the answer to this question is no longer correct. The new $lookup operator added to the aggregation pipeline is essentially identical to a left outer join:
https://docs.mongodb.org/master/reference/operator/aggregation/lookup/#pipe._S_lookup
From the docs:
{
$lookup:
...
Rails new vs create
Why is there a need to define a new method in RESTful controller, follow it up with a create method?
4 Answers
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Postgres unique constraint vs index
...read this in the doc:
ADD table_constraint [ NOT VALID ]
This form adds a new constraint to a table using the same syntax as CREATE TABLE, plus the option NOT VALID, which is currently only allowed for foreign key constraints. If the constraint is marked NOT VALID, the potentially-lengthy initial c...
How to copy a collection from one database to another in MongoDB
...b.<collection_name>.find().forEach(function(d){ db.getSiblingDB('<new_database>')['<collection_name>'].insert(d); });
Please note that with this, the two databases would need to share the same mongod for this to work.
Besides this, you can do a mongodump of a collection from on...
Disable/enable an input with jQuery?
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Just for the sake of new conventions && making it adaptable going forward (unless things change drastically with ECMA6(????):
$(document).on('event_name', '#your_id', function() {
$(this).removeAttr('disabled');
});
and
$(document...
How set the android:gravity to TextView from Java side in Android
...xtView ta = (TextView) findViewById(R.layout.text_view);
LayoutParams lp = new LayoutParams();
lp.gravity = Gravity.CENTER_HORIZONTAL;
ta.setLayoutParams(lp);
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How do you query for “is not null” in Mongo?
...ue. This includes documents that do not contain the field.
So in your provided case following query going to return all the documents with imageurl field exists and having not null value:
db.mycollection.find({ 'imageurl' : { $exists: true, $ne: null } });
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