Ionic 2数据库类型错误：executeSql

Question

我一直在试图制作一个简单的表格，然后在其中插入数据以开发一种理解，即Ionic 2框架如何工作，但我遇到了问题并无法解决问题。我尝试了不同的谷歌解决方案，但他们都没有工作。

注：我是新来的Ionic 2和最初的本地Android开发人员。

import { Component } from '@angular/core'; 
import { IonicPage, NavController, NavParams, ToastController, Platform } from 'ionic-angular'; 
import { SQLite, SQLiteObject } from '@ionic-native/sqlite'; 
/** 
* Generated class for the AddProductsPage page. 
* 
* See http://ionicframework.com/docs/components/#navigation for more info 
* on Ionic pages and navigation. 
*/ 
@IonicPage() 
@Component({ 
    selector: 'page-add-products', 
    templateUrl: 'add-products.html', 

}) 
export class AddProductsPage { 
    productName: string; 
    sqlstorage: SQLite; 
    items: Array<Object>; 
    db: SQLiteObject; 
    mesg: string; 
    constructor(public navCtrl: NavController, public navParams: NavParams, private toastCtrl: ToastController, public platform: Platform) { 


    this.platform.ready().then(() => { 
     this.sqlstorage = new SQLite(); 

     this.sqlstorage.create({ name: "test.db", location: "default" }).then(() => { 
     console.log("SuccessDB"); 
     this.db.executeSql("CREATE TABLE IF NOT EXISTS product (ProductID INTEGER PRIMARY KEY AUTOINCREMENT, ProductName TEXT)", []); 
     // this.createTables(); 
     }, (err) => { 
     console.log("DB !!! ", err); 
     }); 
    }); 
    } 
    presentToast() { 
    let toast = this.toastCtrl.create({ 
     message: this.mesg, 
     duration: 3000, 
     position: 'top' 
    }); 

    toast.onDidDismiss(() => { 
     console.log('Dismissed toast'); 
    }); 

    toast.present(); 
    } 
    addProduct() { 


    this.addItem("insert into product (productName) values(?)", this.productName); 
    this.findAll(); 
    } 

    public createTables() {  
    this.db.executeSql("CREATE TABLE IF NOT EXISTS product (ProductID INTEGER PRIMARY KEY AUTOINCREMENT, ProductName TEXT)", []); 
    } 

    public addItem(q: string, param: string) { 
    this.db.executeSql(q, param).then((data) => { 
     console.log("Success"); 
    }, (e) => { 
     console.log("Error : " + JSON.stringify(e.err)); 
    }); 
    } 

    public findAll() { 
    this.db.executeSql("SELECT * FROM items", []).then((data) => { 
     this.items = []; 
     if (data.rows.length > 0) { 
     for (var i = 0; i < data.rows.length; i++) { 
      this.items.push(data.rows.item(i)); 
      this.mesg = data.rows.item(i); 
      console.log(this.mesg); 
     } 
     } 
    }, (e) => { 
     this.mesg = "Errot: " + JSON.stringify(e); 
     console.log("Errot: " + JSON.stringify(e)); 
    }); 
    this.presentToast(); 
    } 
} 

继承人从装置的故障

OPEN database: test.db SQLitePlugin.js:175 
new transaction is waiting for open operation SQLitePlugin.js:106 
OPEN database: test.db - OK 
ERROR 
Error {rejection: TypeError, promise: t, zone: r, task: t} 
message: "Uncaught (in promise): TypeError: Cannot call method 'executeSql' of undefined↵TypeError: Cannot call method 'executeSql' of undefined↵ at AddProductsPage.createTables (file:///android_asset/www/build/main.js:58248:17)↵ at file:///android_asset/www/build/main.js:58226:23↵ at t.invoke (file:///android_asset/www/build/polyfills.js:3:9283)↵ at Object.inner.inner.fork.onInvoke (file:///android_asset/www/build/main.js:4649:37)↵ at t.invoke (file:///android_asset/www/build/polyfills.js:3:9223)↵ at r.run (file:///android_asset/www/build/polyfills.js:3:4452)↵ at file:///android_asset/www/build/polyfills.js:3:14076↵ at t.invokeTask (file:///android_asset/www/build/polyfills.js:3:9967)↵ at Object.inner.inner.fork.onInvokeTask (file:///android_asset/www/build/main.js:4640:37)↵ at t.invokeTask (file:///android_asset/www/build/polyfills.js:3:9888)" 
promise: t 
rejection: TypeError 
stack: (...) 
get stack: function() { [native code] } 
set stack: function() { [native code] } 
task: t 
zone: r 
__proto__: d 
main.js:1584 
defaultErrorLogger main.js:1584 
ErrorHandler.handleError main.js:1644 
IonicErrorHandler.handleError main.js:117966 
onError.subscribe.next main.js:5278 
schedulerFn main.js:4351 
SafeSubscriber.__tryOrUnsub main.js:15685 
SafeSubscriber.next main.js:15632 
Subscriber._next main.js:15572 
Subscriber.next main.js:15536 
Subject.next main.js:18926 
EventEmitter.emit main.js:4337 
NgZone.triggerError main.js:4709 
inner.inner.fork.onHandleError main.js:4670 
t.handleError polyfills.js:3 
r.runGuarded polyfills.js:3 
(anonymous function) polyfills.js:3 
n.microtaskDrainDone polyfills.js:3 
o 

编辑：

代码错误而无法执行插入查询。 （addProduct方法在点击触发器上执行。）

import { Component } from '@angular/core'; 
import { IonicPage, NavController, NavParams, ToastController, Platform } from 'ionic-angular'; 
import { SQLite, SQLiteObject } from '@ionic-native/sqlite'; 
/** 
* Generated class for the AddProductsPage page. 
* 
* See http://ionicframework.com/docs/components/#navigation for more info 
* on Ionic pages and navigation. 
*/ 
@IonicPage() 
@Component({ 
    selector: 'page-add-products', 
    templateUrl: 'add-products.html', 

}) 
export class AddProductsPage { 
    productName: string; 
    sqlstorage: SQLite; 
    items: Array<Object>; 
    db: SQLiteObject; 
    mesg: string; 
    constructor(public navCtrl: NavController, public navParams: NavParams, private toastCtrl: ToastController, public platform: Platform) { 


    this.platform.ready().then(() => { 
     this.sqlstorage = new SQLite(); 
     this.sqlstorage.create({ 
     name: 'data.db', 
     location: 'default' 
     }).then((db: SQLiteObject) => { 
     this.db = db; 
     console.log("Opened"); 

     db.executeSql("CREATE TABLE IF NOT EXISTS product (ProductID INTEGER PRIMARY KEY AUTOINCREMENT, ProductName TEXT)", []); 
     db.executeSql("insert into product (ProductID,ProductName) values(3,'jhkj')", []); 

     }).catch(e => { 
     console.log(e); 
     }); 
    }); 
    } 
    presentToast() { 
    let toast = this.toastCtrl.create({ 
     message: this.mesg, 
     duration: 3000, 
     position: 'top' 
    }); 

    toast.onDidDismiss(() => { 
     console.log('Dismissed toast'); 
    }); 

    toast.present(); 
    } 


    addProduct() { 
     // this.sqlstorage = new SQLite(); 


// this.sqlstorage.create({ 
    // name: 'data.db', 
    // location: 'default' 
    // }).then((db: SQLiteObject) => { 
    // console.log("Opened"); 
    return new Promise((resolve, reject) => { 
     this.db.executeSql("insert into product (productName) values(?)", this.productName).then((data) => { 
     resolve(data); 
     console.log("resolve"); 
     }, (error) => { 
     reject(error); 
     console.log("reject"); 
     }); 
    }); 
    // this.addItem("insert into product (productName) values(?)", this.productName, db); 
    // this.findAll(db); 
    // }).catch(e => { 
    // console.log(e); 
    // }); 

    } 

    public createTables() { 
    this.db.executeSql("CREATE TABLE IF NOT EXISTS product (ProductID INTEGER PRIMARY KEY AUTOINCREMENT, ProductName TEXT)", []); 
    } 

    public addItem(q: string, param: string, db: SQLiteObject) { 
    db.executeSql(q, param).then((data) => { 
     console.log("Success"); 
    }, (e) => { 
     console.log("Error : " + JSON.stringify(e.err)); 
    }); 
    } 

    public findAll(db: SQLiteObject) { 
    db.executeSql("SELECT * FROM product", []).then((data) => { 
     this.items = []; 
     if (data.rows.length > 0) { 
     for (var i = 0; i < data.rows.length; i++) { 
      this.items.push(data.rows.item(i)); 
      this.mesg = data.rows.item(i); 
      console.log(this.mesg); 
     } 
     } 
    }, (e) => { 
     this.mesg = "Errot: " + JSON.stringify(e); 
     console.log("Errot: " + JSON.stringify(e)); 
    }); 
    this.presentToast(); 
    } 
} 

Answer 1

由于您尝试使用未初始化的SQLiteObject数据库，因此发生该错误。当你使用SQLite的create方法时，它会返回一个SQLiteObject，你可以用它来执行你的SQL查询。这里是一个例子 -

this.sqlite.create({ 
     name: 'data.db', 
     location: 'default' 
    }).then((db: SQLiteObject) => { 
     console.log("Opened");   
     db.executeSql("CREATE TABLE IF NOT EXISTS product (ProductID INTEGER PRIMARY KEY AUTOINCREMENT, ProductName TEXT)", []); 
    }).catch(e => { 
     console.log(e);   
    });