無法打開數據庫寫作

Question

我試圖從數據庫中獲取某些內容或向崩潰的數據庫寫入內容時，我的數據庫出現了一些問題，這些數據庫是在我的應用程序中實現的。我還發現了導致崩潰的線條，但我真的不知道如何解決它。

下面是我的數據庫代碼+錯誤訊息

public class DatabaseHelper extends SQLiteOpenHelper { 

    // Logcat tag 
    private static final String LOG = "DatabaseHelper"; 

    // Database Version 
    private static final int DATABASE_VERSION = 1; 

    // Database Name 
    private static final String DATABASE_NAME = "routeLogBook"; 

    // Table Names 
    private static final String TABLE_DRIVE = "drive"; 
    private static final String TABLE_ROUTE = "route"; 
    private static final String TABLE_CAR = "car"; 
    private static final String TABLE_FUEL = "fuel"; 
    private static final String TABLE_FUELCALC = "fuelcalc"; 

    // Drive 
    private static final String KEY_DRIVE_ID = "did"; 
    private static final String KEY_DRIVE_BEGIN = "begin"; 
    private static final String KEY_DRIVE_END = "end"; 
    private static final String KEY_DRIVE_CAR = "car"; 

    // Route 
    private static final String KEY_ROUTE_ID = "rid"; 
    private static final String KEY_ROUTE_DATE = "date"; 
    private static final String KEY_ROUTE_LATITUDE = "latitude"; 
    private static final String KEY_ROUTE_LONGITUDE = "longitude"; 
    private static final String KEY_ROUTE_DRIVE = "drive"; 

    // Car 
    private static final String KEY_CAR_ID = "cid"; 
    private static final String KEY_CAR_NAME = "name"; 
    private static final String KEY_CAR_MARQUE = "marque"; 
    private static final String KEY_CAR_FUEL = "fuel"; 

    // Fuel 
    private static final String KEY_FUEL_ID = "fid"; 
    private static final String KEY_FUEL_FUEL = "fuel"; 


    // Table Create Statements 
    // Drive table create statement 
    private static final String CREATE_TABLE_DRIVE = "CREATE TABLE " 
      + TABLE_DRIVE + "(" 
      + KEY_DRIVE_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," 
      + KEY_DRIVE_BEGIN + " TEXT," 
      + KEY_DRIVE_END + " TEXT," 
      + KEY_DRIVE_CAR + " INTEGER," 
      + " FOREIGN KEY (" + KEY_DRIVE_CAR 
      + ") REFERENCES " + TABLE_CAR + " (" + KEY_CAR_ID + ")" + ");"; 

    // Route table create statement 
    private static final String CREATE_TABLE_ROUTE = "CREATE TABLE " 
      + TABLE_ROUTE + "(" 
      + KEY_ROUTE_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," 
      + KEY_ROUTE_DATE + " TEXT," 
      + KEY_ROUTE_LATITUDE + " TEXT," 
      + KEY_ROUTE_LONGITUDE + " TEXT," 
      + KEY_ROUTE_ID + " INTEGER," 
      + " FOREIGN KEY (" + KEY_ROUTE_DRIVE 
      + ") REFERENCES " + TABLE_DRIVE + " (" + KEY_DRIVE_ID + ")" + ");"; 

    // Car table create statement 
    private static final String CREATE_TABLE_CAR = "CREATE TABLE " 
      + TABLE_CAR + "(" 
      + KEY_CAR_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," 
      + KEY_CAR_NAME + " TEXT," 
      + KEY_CAR_MARQUE + " TEXT," 
      + KEY_CAR_FUEL + " INTEGER," 
      + " FOREIGN KEY (" + KEY_CAR_FUEL 
      + ") REFERENCES " + TABLE_FUEL + " (" + KEY_FUEL_ID + ")" + ");"; 

    // Fuel table create statement 
    private static final String CREATE_TABLE_FUEL = "CREATE TABLE " 
      + TABLE_FUEL + "(" + KEY_FUEL_ID 
      + " INTEGER PRIMARY KEY AUTOINCREMENT," + KEY_FUEL_FUEL + " TEXT" 
      + ");"; 

    // FuelCalc table create statement 
    // TODO 

    public DatabaseHelper(Context context) { 
     super(context, DATABASE_NAME, null, DATABASE_VERSION); 
    } 

    @Override 
    public void onOpen(SQLiteDatabase db) { 
     super.onOpen(db); 
     if (!db.isReadOnly()) { 
      // Enable foreign key constraints 
      db.execSQL("PRAGMA foreign_keys=ON;"); 
     } 
    } 

    @Override 
    public void onCreate(SQLiteDatabase db) { 

     // creating required tables 
     db.execSQL(CREATE_TABLE_FUEL); 
     db.execSQL(CREATE_TABLE_CAR); 
     db.execSQL(CREATE_TABLE_DRIVE); This one and the one the line below are the cause of the crashes i think 
     db.execSQL(CREATE_TABLE_ROUTE); 

    } 

    @Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
     // on upgrade drop older tables 
     db.execSQL("DROP TABLE IF EXISTS " + CREATE_TABLE_FUEL); 
     db.execSQL("DROP TABLE IF EXISTS " + CREATE_TABLE_CAR); 
     db.execSQL("DROP TABLE IF EXISTS " + CREATE_TABLE_DRIVE); 
     db.execSQL("DROP TABLE IF EXISTS " + CREATE_TABLE_ROUTE); 

     // create new tables 
     onCreate(db); 
    } 


    // close database 
    public void closeDB() { 
     SQLiteDatabase db = this.getReadableDatabase(); 
     if (db != null && db.isOpen()) 
      db.close(); 
    } 
} 

錯誤日誌，

01-23 13:12:33.530: E/SQLiteOpenHelper(880): Couldn't open routeLogBook for writing (will try read-only): 
01-23 13:12:33.530: E/SQLiteOpenHelper(880): android.database.sqlite.SQLiteException: Can't downgrade database from version 2 to 1 

Answer 1

android.database.sqlite.SQLiteException: Can't downgrade database from version 2 to 1 

您的設備有2版本的數據庫文件，而你的代碼試圖打開一個數據庫與版本1.您不提供onDowngrade()回調，以便拋出異常。

只需刪除舊數據庫即可創建新數據庫。卸載應用程序將刪除數據庫文件。