大约有 18,361 项符合查询结果（耗时：0.0209秒） [XML]
Preventing Laravel adding multiple records to a pivot table
...condition like this one :
if (! $cart->items->contains($newItem->id)) {
$cart->items()->save($newItem);
}
Or/and you can add unicity condition in your database, it would throw an exception during an attempt of saving a doublet.
You should also take a look at the more straightf...
SQL Server indexes - ascending or descending, what difference does it make?
...y Optimiser's point of view.
For the table definition
CREATE TABLE T1( [ID] [int] IDENTITY NOT NULL,
[Filler] [char](8000) NULL,
PRIMARY KEY CLUSTERED ([ID] ASC))
The Query
SELECT TOP 10 *
FROM T1
ORDER BY ID DESC
Uses an ordered scan with scan direction BAC...
MySQL Multiple Joins in one query?
... dashboard_data.headline, dashboard_data.message, dashboard_messages.image_id, images.filename
FROM dashboard_data
INNER JOIN dashboard_messages
ON dashboard_message_id = dashboard_messages.id
INNER JOIN images
ON dashboard_messages.image_id = images.image_id
However be ...
When to use EntityManager.find() vs EntityManager.getReference() with JPA
...ormal) where I use the EntityManager.getReference(LObj.getClass(), LObj.getId()) to get a database entity and then pass the returned object to be persisted in another table.
...
Rest with Express.js nested router
...
You can nest routers by attaching them as middleware on an other router, with or without params.
You must pass {mergeParams: true} to the child router if you want to access the params from the parent router.
mergeParams was introduced in Express 4.5.0 (Jul 5 2014)...
How to count occurrences of a column value efficiently in SQL?
...
SELECT age, count(age)
FROM Students
GROUP by age
If you need the id as well you could include the above as a sub query like so:
SELECT S.id, S.age, C.cnt
FROM Students S
INNER JOIN (SELECT age, count(age) as cnt
FROM Students
GROUP BY ag...
How to transfer some data to another Fragment?
...lass implements Serializable {
private static final long serialVersionUID = -2163051469151804394L;
private int id;
private String created;
}
In you FromFragment:
Bundle args = new Bundle();
args.putSerializable(TAG_MY_CLASS, myClass);
Fragment toFragment = new ToFragment();
toFragment...
How do you obtain a Drawable object from a resource id in android package?
...o use the code below (or something like it) to get an object from the android.R.drawable.* package?
6 Answers
...
How to break a line of chained methods in Python?
...l parenthesis:
subkeyword = (
Session.query(Subkeyword.subkeyword_id, Subkeyword.subkeyword_word)
.filter_by(subkeyword_company_id=self.e_company_id)
.filter_by(subkeyword_word=subkeyword_word)
.filter_by(subkeyword_active=True)
.one()
)
...
Check Whether a User Exists
...
You can also check user by id command.
id -u name gives you the id of that user.
if the user doesn't exist, you got command return value ($?)1
And as other answers pointed out: if all you want is just to check if the user exists, use if with id directl...