php 如何通过laravel中的外键检索记录的完整数据？
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How to retrieve full data of record by its foreign key in laravel?
提问by user2551866
I've been trying to figure out the proper way to get all the data from a record via a foreign key. I have simple app where users can add books to their "bookshelf".
我一直试图找出通过外键从记录中获取所有数据的正确方法。我有一个简单的应用程序，用户可以在其中将书籍添加到他们的“书架”中。
Here are my tables:
这是我的表：
USERS
用户
ID | NAME |
BOOKS
图书
ID | PAGES | NUMBER_OF_CHAPTERS
BOOKSHELF
书架
ID | USER_ID (foreign key to `users.id`) |
BOOKSHELF_BOOKS
书架_BOOKS
ID | BOOKSHELF_ID (foreign key to `bookshelf.id`) | BOOKS_ID (foreign key to `books.id`)
In my Eloquent Models, a bookshelfhasMany books and bookshelf_booksbelongsTo a bookshelfand I have set those up in my models.
在我的Eloquent模型中， a bookshelfhasMany books 和bookshelf_booksBeingsTo abookshelf并且我已经在我的模型中设置了这些。
What happens is users create a "bookshelf" and add books to it from the list of books.
发生的事情是用户创建一个“书架”并从书籍列表中向其中添加书籍。
I'm at the point where I need to render the bookshelf with the user's books.
我现在需要用用户的书籍渲染书架。
When I retrieve my bookshelf books with a call like Bookshelf::find($id)->books, the books that belong to that bookshelf return just fine..but only columns from the bookshelf table. So I get in return the bookshelf id, the user id, and the book id.
当我使用 Bookshelf::find($id)->books 之类的调用检索我的书架书籍时，属于该书架的书籍返回得很好……但只有书架表中的列。所以我得到书架 id、用户 id 和书 id 的回报。
What I want to have returned is all the data of the book itself when i query for books in the bookshelf, not just it's id. E.G. [{"book_id":1, "pages":364, "number_of_chapters":14},{"book_id":2, "pages":211, "number_of_chapters":9}].
当我在书架中查询书籍时，我想要返回的是书籍本身的所有数据，而不仅仅是它的 id。EG [{"book_id":1, "pages":364, "number_of_chapters":14},{"book_id":2, "pages":211, "number_of_chapters":9}]。
I've been scratching my head all day trying to figure out how to take this "join" one step further in Laravel/Eloquent ORM.
我整天都在挠头，试图弄清楚如何在 Laravel/Eloquent ORM 中更进一步地进行这种“加入”。
Would love any help with this, thanks!!
希望得到任何帮助，谢谢！！
回答by Laurence
Just eager load the relationship
Change
改变
Bookshelf::find($id)->books
to
到
Bookshelf::with('books')->find($id)->books
回答by Kylie
What about just doing it manually, and building your own array.
仅手动执行并构建自己的阵列怎么样。
$bookshelf = Bookshelf::find($id)->books;
$thebooks = array();
foreach($bookshelf as $val){
$book = Book::find($val->book_id);
$thebooks[] = $book;
}
Then just return $thebooksto the View. Which will be an array of book models.
然后只需返回$thebooks视图。这将是一系列书籍模型。
回答by user1669496
What you have should be correct.
你所拥有的应该是正确的。
$bookshelf = Bookshelf::find($id)->books;
$bookshelf = Bookshelf::find($id)->books;
To get your books, you would create a loop...
为了得到你的书，你会创建一个循环......
@foreach($bookshelf->books as $book)
{{ $book->name }}
{{ $book->title }}
@endforeach
To take this further, if you had an Author model which your books would belongTo(), you could even do something like..
更进一步，如果你有一个 Author 模型，你的书belongTo()会这样做，你甚至可以做类似的事情。
@foreach($bookshelf->books as $book)
{{ $book->name }}
{{ $book->title }}
{{ $book->author->name }}
@endforeach
回答by Raj Jagani
Try this query
试试这个查询
SELECT b.id, b.pages, b.number_of_chapters
FROM bookshelf bs
JOIN bookshelf_books bsb ON bsb.bookshelf_id = bs.id
JOIN books b ON b.id = bsb.books_id
WHERE bs.id = "Id of bookshelf"
回答by Vishnu Kant Maurya
SELECT *
FROM BOOKSHELF_BOOKS
JOIN BOOKSHELF ON BOOKSHELF_BOOKS.BOOKSHELF_ID = BOOKSHELF.ID
JOIN USERS.ID = BOOKSHELF.USER_ID
Try this sql statement, it will work.
试试这个 sql 语句，它会起作用。
