android.database.sqlite.SQLiteException：不能从0版本升级只读数据库1

Question

我得到的android：android.database.sqlite.SQLiteException

无法升级只读数据库从版本0到1：/data/data/com.tuto.ListViewApp2_SQLite/databases/countryDB

当我运行模拟器它不启动，它说“不幸appName已停止”，所以任何机构可以帮助我吗？

这是我的MainActivity类别：

package com.tuto.ListViewApp2_SQLite; 

import com.tuto.ListViewApp2_SQLite.R; 

import android.app.Activity; 
import android.database.Cursor; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteDatabase.CursorFactory; 
import android.os.Bundle; 
import android.provider.BaseColumns; 
import android.widget.ListView; 
import android.widget.SimpleCursorAdapter; 

public class MainActivity extends Activity { 

    private CountryDB countryDatabase = null; 
    private Cursor countries = null; 
    private ListView lvCountries = null; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     //Create the database helper 
     CursorFactory factory = null; 
     countryDatabase = new CountryDB(this, "countryDB", factory); 

     String[] columnNames = {"Name", "Pop", "Area", BaseColumns._ID}; 
     lvCountries = (ListView) findViewById(R.id.lvCountries); 

     int[] targetLayoutIDs = {R.id.textName, R.id.textPop, R.id.textArea}; 

     SQLiteDatabase db = countryDatabase.getReadableDatabase(); 
     countries = db.query("countries", columnNames, null, null, null, null, null); 
     SimpleCursorAdapter adapter = new SimpleCursorAdapter(this, R.layout.country_item, 
       countries, columnNames, targetLayoutIDs, 0);  
     lvCountries.setAdapter(adapter); 
    } 

    @Override 
    protected void onPause() { 
     super.onPause(); 
     countryDatabase.close(); 
    } 
} 

这我SQLiteOpenHelper的子类：

package com.tuto.ListViewApp2_SQLite; 

import android.content.Context; 
import android.database.sqlite.SQLiteDatabase; 
import android.database.sqlite.SQLiteDatabase.CursorFactory; 
import android.database.sqlite.SQLiteOpenHelper; 

public class CountryDB extends SQLiteOpenHelper { 

    private static final int DB_VERSION = 1; 
    private static final String COUNTRY_TABLE_NAME = "countries"; 

    public CountryDB(Context context, String name, CursorFactory factory) { 
     super(context, name, factory, DB_VERSION); 
    } 

    @Override 
    public void onCreate(SQLiteDatabase dbCountries) { 
     createTable(dbCountries); 
    } 

    @Override 
    public void onUpgrade(SQLiteDatabase dbCountries, int oldVersion, int newVersion) { 
     String dropSQL = "DROP TABLE IF EXISTS " + COUNTRY_TABLE_NAME +";"; 
     dbCountries.execSQL(dropSQL); 
     createTable(dbCountries); 
    } 

    private void createTable(SQLiteDatabase dbCountries){ 
     String createSQL = "CREATE TABLE "+COUNTRY_TABLE_NAME+" ("+ 
       "_id INTEGER PRIMARY KEY AUTOINCREMENT, "+ 
       "Name TEXT, "+ 
       "Pop TEXT, "+ 
       "Area TEXT);"; 
     dbCountries.execSQL(createSQL); 

     String insertSQL = "INSERT INTO " + COUNTRY_TABLE_NAME + 
       " (Name, Pop, Area) " + 
       "SELECT 'South Korea' AS NAME, '41,769,726' AS Pop, '1,068,296' AS Area"+ 
       " UNION SELECT 'Australia', '21,766,711', '2,967,893'" + 
       " UNION SELECT 'India' , '1,189,172,906', '1,269,338',+" + 
       " UNION SELECT 'United States', '313,232,044', '3,718,691';"; 
     dbCountries.execSQL(insertSQL); 

    } 
} 

Answer 1

您的insertSQL未执行并失败。这就是为什么你的数据库没有升级。插入查询在第二个最后一个语句中有一个逗号和一个加号，导致查询无效。

尝试这个 -

String insertSQL = "INSERT INTO " + COUNTRY_TABLE_NAME + 
       " (Name, Pop, Area) " + 
       "SELECT 'South Korea' AS NAME, '41,769,726' AS Pop, '1,068,296' AS Area"+ 
       " UNION SELECT 'Australia', '21,766,711', '2,967,893'" + 
       " UNION SELECT 'India' , '1,189,172,906', '1,269,338'" + 
       " UNION SELECT 'United States', '313,232,044', '3,718,691';"; 

Answer 2

你有一个只读的文件系统已经数据库。它的版本是0.你试图升级到版本1.问题是它的只读，所以你不能改变它。最简单的解决方案是卸载并重新安装应用程序，以摆脱旧的。或者检查旧数据库的存在并将其先删除。其中任何一个都会丢失数据，但基于您的onUpgrade代码，无论如何您都可以使用它。