问题
I'm trying to upgrade my project L5.1 -> L5.2. In upgrade guide there's one thing which isn't clear for me:
The
listsmethod on the Collection, query builder and Eloquent query builder objects has been renamed topluck. The method signature remains the same.
That's ok, rename refactoting from lists() to pluck() isn't a problem. But what with useful pluck() method which was in L5.0 and L5.1?
From the 5.0 documentation:
Retrieving A Single Column From A Row
$name = DB::table('users')->where('name', 'John')->pluck('name');
What is the alternative for old pluck() method in L5.2?
UPDATE:
Example:
var_dump(DB::table('users')->where('id', 1)->pluck('id'));
L5.1:
// int(1)
L5.2:
// array(1) { [0]=> int(1) }
回答1:
The current alternative for pluck() is value().
回答2:
laravel pluck returns an array
if your query is:
$name = DB::table('users')->where('name', 'John')->pluck('name');
then the array is like this (key is the index of the item. auto incremented value):
[
1 => "name1",
2 => "name2",
.
.
.
100 => "name100"
]
but if you do like this:
$name = DB::table('users')->where('name', 'John')->pluck('name','id');
then the key is actual index in the database.
key||value
[
1 => "name1",
2 => "name2",
.
.
.
100 => "name100"
]
you can set any value as key.
回答3:
In Laravel 5.1+, you can use the value() instead of pluck.
To get first occurence, You can either use
DB::table('users')->value('name');
or use,
DB::table('users')->where('id', 1)->pluck('name')->first();
回答4:
In the original example, why not use the select() method in your database query?
$name = DB::table('users')->where('name', 'John')->select("id");
This will be faster than using a PHP framework, for it'll utilize the SQL query to do the row selection for you. For ordinary collections, I don't believe this applies, but since you're using a database...
Larvel 5.3: Specifying a Select Clause
来源:https://stackoverflow.com/questions/34405138/laravel-5-2-pluck-method-returns-array