为什么 Knex 将空值插入我的 table 数据库？

Question

我有一个通过 express 连接的 SQLite 数据库，并且有控制器使用 express 路由连接前端和后端。

Table database

  return knex.schema.createTable('stocks', (table)  => {
          table.string('ticker')
          table.date('date')
          table.integer('open')
          table.integer('close')
          table.integer('high')
          table.integer('last')
          table.integer('volume')
        })
        .then(() => {
         
          console.log('Table \'stocks\' created')
        })
        .catch((error) => {
          console.error(`There was an error creating table: ${error}`)
        })
      }
    })
    .then(() => {
      // Log success message
      console.log('Ayree')
    })
    .catch((error) => {
      console.error(`There was an error setting up the database: ${error}`)
    })

Knex Insert Rows

exports.booksCreate = async (req, res) => {
  // Add new book to database
  knex('stocks')
    .insert({ // insert new record, a book
      "ticker": req.body.ticker,
      'date': req.body.date,
      'open': req.body.open,
      'close': req.body.close,
      'high': req.body.high,
      'last': req.body.last,
      'volume': req.body.volume,
    })
    .then(() => {
      // Send a success message in response
      res.json({ message: ` \'${req.body.ticker}\' added at ${req.body.date} created.` })
    })
    .catch(err => {
      // Send a error message in response
      res.json({ message: `There was an error creating ${req.body.ticker}  ${err}` })
    })
}

React Front End

// Create Bookshelf component
export const Bookshelf = () => {
  // Prepare states
   const [stock, setStock] = useState([])
   const [stockApi, setStockApi] = useState([])
  const [loading, setLoading] = useState(true)

  // Fetch all books on initial render
  useEffect(() => {
   
    getStockData();
    handleBookCreate();
  }, [])


  //StockData
const getStockData = ()  => { 
    axios
    .get("http://api.marketstack.com/v1/intraday/latest?access_key=72ad8c2f489983f30aaedd0181414b43&symbols=AAPL"       )
    .then( da => {
       setStock(da.data.data[0]) 
        console.log(da.data.data[0])
    } )
} 

// Create new book
  const handleBookCreate = () => {
    // Send POST request to 'books/create' endpoint
    axios
      .post('http://localhost:4001/books/create', { 
        ticker: stock.symbol,
        date: stock.date,
        open: stock.open,
        close: stock.close,
        high: stock.high,
        last: stock.last,
        volume: stock.volume,
      })
      .then(res => {
        console.log(res.data)

        // Fetch all books to refresh
        // the books on the bookshelf list
        fetchBooks()
      })
      .catch(error => console.error(`There was an error creating the ${stock} book: ${error}`))
  }

这里的问题出在前端，当我使用 stock.symbol 时，我得到一个空值，但是当我用“文本”替换 stock.symbol 时，我得到值文本。我在这里做错了什么？谢谢！

P.S - 这是常量库存

close: 115.08
date: "2020-10-09T00:00:00+0000"
exchange: "IEXG"
high: 116.4
last: 114.97
low: 114.5901
open: 116.25
symbol: "AAPL"
volume: 82322071
__proto__: Object

Answer 1

经过一段时间阅读 HTTP 调用及其执行方式。这个解决方案对我有用。

 useEffect( () => {

const fetchData = async ( ) => { 

  const getit =  await getStockData(); setStock(getit); 
    handleBookCreate(getit); 
    } 
         fetchData();

  }, [])

基本上在初始渲染 useEffect 上，进行 API 调用 getStockData() 并且等待将在承诺执行后设置库存 setStock 挂钩。只有这样 stock 才会包含 handleBookCreate() 向服务器路由器发送 POST 请求以执行在我的 table 数据库中插入记录的功能所需的数据。

为什么 Knex 将空值插入我的 table 数据库？

Why does Knex insert null values into my table database?

mysql

node.js

reactjs

express

knex.js