(laravel 文档阅读记录)
model
model casting
模型(App\Models\Flag::Illuminate\Database\Eloquent\Model)
创建模型 $flag = new Flag(); 或 $flag = Flag::resolveInstance();
$request->input('date') 可以是 "2021-01-05 01:00:00" 字符串,
通过 Carbon::parse($request->input('date') ?? now_local())
,
它可以被转化为 CarbonInterface::DateTimeInterface
模型的属性可能由 $request->input('date') 获得
$flag = Flag::resolveInstance();
$flag->fill([
'user_id' => $event->assessment->user_id,
'date_id' => $event->assessment->date_id,
'name' => 'technical_focus',
'value' => $assessment->getAnswer('technical_focus'),
'recorded_by_id' => $event->assessment->user_id,
]);
$flag->utcDate()->associate($event->assessment->utc_date_id); // a date can has many flags. 这里设定了 flags table 条目的 utc_date_id 栏位
$flag->save();
给一个模型的属性指定类型 (cast type, 比如 timestamp),方便后续模型操作 1
relationship
a Model 是一个对象
a Relation 是一个对象
$post = Post::find(1);
$comments = $post->comments;
// 这里是初始化了一个 Relation 对象, 让它完成了一次
`SELECT * FROM Comments WHERE post_id=1;`
的 SQL query, 找到很多条目了之后组装成一个 Collection 赋值给 $comments
模型和 relationship 的关系是什么?一个 one-to-many relationship 里,比如 post hasMany comments ,那么:
1
$post 就会自带很多方法或 property 比如
use App\Models\Post;
$comments = Post::find(1)->comments;
foreach ($comments as $comment) {
// ...
}
2
Eloquent will automatically determine the proper foreign key column for the Comment model. By convention, Eloquent will take the "snake case" name of the parent model and suffix it with _id
. So, in this example, Eloquent will assume the foreign key column on the Comment model is post_id.
Once the relationship method has been defined, we can access the collection of related comments by accessing the comments
property.
3
Since all relationships also serve as query builders, you may add further constraints to the relationship query by calling the comments method and continuing to chain conditions onto the query.
$comment = Post::find(1)->comments()
->where('title', 'foo')
->first();
4
什么是 query builder
(initial query 1 )
relationship 提供的 methods 是 query builder 1
Since relationships also serve as powerful query builders, defining relationships as methods provides powerful method chaining and querying capabilities.
$user->posts()->where('active', 1)->get();
relationship
Database tables are often related to one another. For example, a blog post may have many comments or an order could be related to the user who placed it.
1
load a relationship
The relationship won't be loaded after associating the id 是什么意思 1? 是指在 A->B 情况里, 若 B is not loaded 则 B 默认为 null
建立模型间关系: 一对多 or 多对多
建立一个 ‘模型间关系’ 的方法是:
多对多关系: sync, 它接受 model 作为参数 sync sync(what)
一对多关系: asscociate, 参数是 model 或 model id int associate(what)
relationship one-to-many relationship
a blog post has many comments
a comment belongs to a post
在 comments table 里有 post_id 栏位
relationship - 通过 belongsTo relationship
父模型更新子模型
在 a model 的视角,
通过 belongsTo relationship, a model "找到" 自己的子模型(实际上找到的是 $post->comments() 这个 relationship)并通过它追加一个属于自己的子模型(构成了新一个 belongsTo relationship, 保存在隐形的联表里? 因为一对多关系不需要显式的联表)。
use App\Models\Comment;
use App\Models\Post;
$comment = new Comment(['message' => 'A new comment.']);
$post = Post::find(1);
$post->comments()->save($comment);
The save method will automatically add the appropriate post_id value to the new Comment model 1. 至此 comment model 处理完毕了,存储在 comments table 的时候 post_id 栏位有值 —— 否则 post_id 栏位 缺值(所谓的未设置外键 ?),这是不对的。
子模型自我更新
在 a child model 的视角,
通过 belongsTo relationship, a child model "关联到 a new parent model" 即 a child model 为自己设定了 parentModel_id 栏位
// user belongs to an account
use App\Models\Account;
$user->account()->associate(Account::find(10));
$user->save();
// 这个叫做 to assign a child model to a new parent model, you may use the `associate` method. In this example, the User model defines a belongsTo relationship to the Account model. This `associate` method will set the foreign key on the child model.
// (对此 user, 更新了 users table 里的它的 account_id 栏位)
// a new parent model 是 account
// comment belongs to a post
use App\Models\Post;
$comment->post()->associate(Post::find(10));
$comment->save();
// a new parent model 是 post
// (对此 comment, 更新了 comments table 里的它的 post_id 栏位)
migration
Schema Builder 数据结构
https://laravel.com/docs/5.0/schema
https://laravel.com/docs/master/migrations#available-column-t...
boolean
integer
unsignedInteger (non-negative)
decimal
misc
doctrine/dbal and config/database.php
1
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