expo-sqlite 返回 undefined 不是 excuteSql 函数中的对象

Posted 2023-03-13

【中文标题】expo-sqlite 返回 undefined 不是 excuteSql 函数中的对象

【英文标题】：expo-sqlite returning undefined is not an object in excuteSql function

【发布时间】：2021-05-22 05:56:46

【问题描述】：

我有这段代码应该让用户登录

反应原生应用

每次点击

登录按钮

总是显示这个错误

undefined 不是对象（评估 'tx.executeSql("SELECT * FROM Student WHERE email = ? AND password = ?", [student.email, student.password]).then'）

这是我写的代码

    //The database connection
    import * as SQLite from 'expo-sqlite';
//const db = SQLite.openDatabase('db.db');
//import SQLite from "react-native-sqlite-storage";
//SQLite.DEBUG(true);
//SQLite.enablePromise(true);

const database_name = "mySchool.db";
const database_version = "1.0";
const database_displayname = "Biometric attendance base";
const database_size = 200000;

const db = SQLite.openDatabase(database_name, database_version, database_name, database_size)

export default db;

    // Import db connection for use
    import db from '../Database';
    getStudent = () => 
        const student = 
          password: this.state.password,
          email: this.state.email,
        ;

        db.transaction((tx) => 
          tx.executeSql("SELECT * FROM Student WHERE email = ? AND password = ?", [
            student.email,
            student.password,
          ], ).then(([tx, results]) => 
            alert(results);
            if (results.rows.length > 0) 
              let row = results.rows.item(0);
              this.props.navigation.navigate('StudentLogin',  data: row );
              //resolve(row);
             else 
              alert('Incorrect email and password comnbination');
            
          );
        );

这是我点击登录按钮时将运行的代码

【问题讨论】：

你能console.log(results) 并展示输出吗

并显示您的db 的声明位置

它是在顶部导入的。

好的，然后将db记录到控制台，然后发布结果

已更新问题。实际上，我正在使用snack.expo.io 来创建应用程序。所以我不知道在哪里可以找到console.log

【参考方案1】：

Referenze

db.transaction((tx) => 
tx.executeSql("SELECT * FROM Student WHERE email = ? AND password = ?", [
    student.email,
    student.password,
], (tx, results) => 
    console.log(result);
)
);