[英]How can I query a particular ID with sequelize.js so I can update it
我正在开发图书库API,用户可以在其中借用和更新。
这是我借书的逻辑:
BorrowBooks(req, res) {
Book.findOne({
where: {
title: req.body.booktitle,
author: req.body.author,
}
})
.then(book => {
if (!book) {
res.status(404).send({
message: "Book not found!"
})
} else {
return Borrower
.create({
booktitle: req.body.booktitle,
borrowDate: Date.now(),
returnDate: null,
userId: req.params.userId,
})
.then(borrower => {
res.status(200).send(borrower)
book.update({
count: book.count - 1,
});
})
.catch((e) => {
return res.status(400).send(e)
})
}
});
},
要退还书,我需要以下内容:
returnBooks(req, res) {
Book.findOne({
where: {
title: req.body.title,
author: req.body.author,
}
})
.then((book) => {
if (!book) {
return res.status(400).send({
message: "There is no book like that!"
})
} else {
book.update({
count: book.count + 1,
})
Borrower.findOne({
where: {
id: req.params.userId,
booktitle: req.body.title,
}
})
.then((returnedBook) => {
returnedBook.update({
returnDate: Date.now()
})
.then(() => res.status(200).send({
message: "book successfully returned",
returnedBook
}))
})
}
})
}
对于一本书,这行得通(我认为),但是,如果用户借用了两本书或更多书,而我尝试退还,则无法使用。
它如何工作,以便返回更多借来的书实例。 它如何注意到借来的新书的新ID?
如果我尝试退还第二本书,则会引发以下错误?
Unhandled rejection TypeError: Cannot read property 'update' of null
at Borrower.findOne.then (C:\Users\okonjiemmanuel\Desktop\hellobooks\server\controllers\book.js:142:23)
at tryCatcher (C:\Users\okonjiemmanuel\Desktop\hellobooks\node_modules\bluebird\js\release\util.js:16:23)
at Promise._settlePromiseFromHandler (C:\Users\okonjiemmanuel\Desktop\hellobooks\node_modules\bluebird\js\release\promise.
js:512:
您是否尝试过使用.findAll?
http://docs.sequelizejs.com/class/lib/model.js~Model.html#static-method-findAll
Book.findAll({
where: {
title: req.body.title,
author: req.body.author
}
})
根据您是否要使用实例模型或原始值,您必须传递一些选项。 即:原始:真实
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