Express + Sqlite3：如何让语句按一定顺序执行？

Question

我正在尝试使用

node

命令执行以下脚本来创建一个表，并在其中插入一个项目。但是，由于某种原因，我的代码在创建表之前就将项目插入表中。我尝试交换语句的索引，但它们仍然以相同的顺序执行。当我使用

sqlite3

打开数据库并手动输入命令时，一切都按预期进行。有没有办法指定我的脚本中哪个语句先执行？

index.js

const express = require("express");
const cors = require("cors");
const sqlite3 = require("sqlite3").verbose();
const app = express();

app.use(cors());

let db = new sqlite3.Database("./database.db", err => {
    try {
        console.log("Successful connection to the database");
    } catch {
        console.error(err.message);
    }
});

statements = ["CREATE TABLE IF NOT EXISTS Products (product TEXT, price INTEGER);", "INSERT INTO Products (product, price) VALUES ('Apple', 5.99);"]
statements.forEach(statement => db.run(statement, err => {
    try {
        console.log(statement + ": successful!");
    } catch {
        console.error(err.message);
    }
}));

app.listen(3000, () => {
    console.log("Connection: http://localhost:3000/")
})

输出：

Connection: http://localhost:3000/
Successful connection to the database
INSERT INTO Products (product, price) VALUES ('Apple', 5.99);: successful!
CREATE TABLE IF NOT EXISTS Products (product TEXT, price INTEGER);: successful!

Answer 1

我认为这是因为 foreach 语句中的 db.run 是异步的。试试这个：

const express = require("express");
const cors = require("cors");
const sqlite3 = require("sqlite3").verbose();
const app = express();

app.use(cors());
// connect to database
let db = new sqlite3.Database("./database.db", err => {
    if (err) { // if fail connection don't create table
        console.error(err.message);
    } else {
        console.log("Successful connection to the database");

        // Create table first
        db.run("CREATE TABLE IF NOT EXISTS Products (product TEXT, price INTEGER);", err => {
            if (err) {
                console.error(err.message);
            } else {
                console.log("Table created successfully");

                // Insert data after table creation
                db.run("INSERT INTO Products (product, price) VALUES ('Apple', 5.99);", err => {
                    if (err) {
                        console.error(err.message);
                    } else {
                        console.log("Data inserted successfully");
                    }
                });
            }
        });
    }
});
app.listen(3000, () => {
    console.log("Connection: http://localhost:3000/")
})