結合來自兩個不同模型 MongoDB 的兩個不同查詢的結果

Question

所以首先我有一個查詢來查找用戶借過的書，它將使用 Borrow 模型進行搜索

const bookqueryinitial = await Borrow.find({borrower_Id : String(_id), borrowStatus: req.query.status}).sort({"borrowDate": -1 }).skip(skip).limit(pageSize);

它會返回這樣的結果

[
   {
     _id: new ObjectId("628ebcc10944a1223397b057"),
     borrower_Id: '6278d1b6b4b7659470572e19',
     borrowedbook_Id: '62710ac63ad1bfc6d1703162',
     borrowStatus: 'pending',
     borrowDate: 2022-05-25T23:33:21.849Z,
     __v: 0
   },
   {
     _id: new ObjectId("628d9c0b9a3dc72f4aa72f1a"),
     borrower_Id: '6278d1b6b4b7659470572e19',
     borrowedbook_Id: '62710ac63ad1bfc6d170314d',
     borrowStatus: 'pending',
     borrowDate: 2022-05-25T03:01:31.416Z,
    __v: 0
    }
 ]

接下來是我將映射結果的borrowedbook_Ids並將它們存儲在一個數組中

const booksinsidequery = bookqueryinitial.map(bookids=>{
      return bookids.borrowedbook_Id
    })

然后我將搜索存儲在數組中的 id 並在 Book 模型中搜索這些 id

 const bookquery = await Book.find({ '_id': { $in: booksinsidequery } });

\\and the result is somethign like this

 [
   {
    _id: new ObjectId("62710ac63ad1bfc6d170314d"),
     title: "Girl who kicked the Hornet's Nest",
     author: 'Larsson, Steig',
     genre: [ 'fiction' ],
     publisher: '',
     dateOfPublication: 2017-10-25T00:00:00.000Z,
     noOfCopies: 14,
     type: 'Article',
     form: 'Fiction',
     isbn: '978-69793-4824559-56755-9',
     dateAdded: 2003-04-23T00:00:00.000Z,
     noOfBookmarks: [ [Object] ],
     noOfLikes: [],

   },
   {
     _id: new ObjectId("62710ac63ad1bfc6d1703162"),
     title: 'We the Nation',
     author: 'Palkhivala',
     genre: [ 'philosophy' ],
     publisher: '',
     dateOfPublication: 2011-11-22T00:00:00.000Z,
     noOfCopies: 94,
     type: 'Book',
     form: 'Non-fiction',
     isbn: '978-65685-4156343-802140-8',
     dateAdded: 2010-06-08T00:00:00.000Z,
     noOfLikes: [],
     noOfBookmarks: []
   }
 ]

現在在將查詢結果發送到客戶端之前，我想將我的初始查詢從 Borrow 模型綁定到我的 Book 模型，最終結果應該是這樣的

 [
   {
    _id: new ObjectId("62710ac63ad1bfc6d170314d"),
     title: "Girl who kicked the Hornet's Nest",
     author: 'Larsson, Steig',
     genre: [ 'fiction' ],
     publisher: '',
     dateOfPublication: 2017-10-25T00:00:00.000Z,
     noOfCopies: 14,
     type: 'Article',
     form: 'Fiction',
     isbn: '978-69793-4824559-56755-9',
     dateAdded: 2003-04-23T00:00:00.000Z,
     noOfBookmarks: [ [Object] ],
     noOfLikes: [],

     //added properties based on matched condition  (Borrow.borrowedbook_Id === Book._id)
     borrowStatus: 'pending',
     borrowDate: 2022-05-25T03:01:31.416Z,
   },
   {
     _id: new ObjectId("62710ac63ad1bfc6d1703162"),
     title: 'We the Nation',
     author: 'Palkhivala',
     genre: [ 'philosophy' ],
     publisher: '',
     dateOfPublication: 2011-11-22T00:00:00.000Z,
     noOfCopies: 94,
     type: 'Book',
     form: 'Non-fiction',
     isbn: '978-65685-4156343-802140-8',
     dateAdded: 2010-06-08T00:00:00.000Z,
     noOfLikes: [],
     noOfBookmarks: [],
     
   //added properties based on matched condition  (Borrow.borrowedbook_Id === Book._id)
     borrowStatus: 'pending',
     borrowDate: 2022-05-25T23:33:21.849Z,
   }
 ]

我怎樣才能獲得這些結果？

Answer 1

您可以使用 MongoDB 提供的聚合框架來實現這一點。

根據您的數據，這里是一個示例： https ://mongoplayground.net/p/DQJIbcqBDKM

• Lookup ：運算符幫助您連接不同集合之間的數據，匹配的數據將在一個數組中。 在這種情況下，稱為借用

• Unwind ：將為指定數組上的每個項目創建一個文檔

• Addfields ：允許您創建新屬性，在這種情況下，您想要的兩個屬性“borrowStatus”和“borrowDate”

• Project ：此操作符允許您在下一階段隱藏或顯示數據。 在這種情況下，0 意味着我們將隱藏一個特定的屬性