如何在android中升级数据库版本？

Question

我想升级我的数据库版本4. 我在清单文件 改变版本的代码和我的数据库openhelper是

@Override 
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
     DTLog.w("Old Version" + oldVersion, "new Version" + newVersion); 
     DTLog.w("UPDATING DB", "Updating database"); 

     if (oldVersion == 1 && newVersion == 2) { 
      db.execSQL("ALTER TABLE moduleRecord ADD COLUMN subtitle1 TEXT"); 
      db.execSQL("ALTER TABLE moduleRecord ADD COLUMN subtitle2 TEXT"); 
      db.delete("moduleRecord", null, null); 

     } 
     else if ((oldVersion == 2&&newVersion == 3)) { 
      db.execSQL("CREATE TABLE " 
        + "moduleDesc" 
        + "(deleteable INTEGER,createable INTEGER,updateable INTEGER,name TEXT,label TEXT,labelfields TEXT,fields TEXT);"); 

     } else { 
      db.execSQL("DROP TABLE IF EXISTS " + "moduleRecord"); 
      db.execSQL("DROP TABLE IF EXISTS " + "ModuleName"); 
      db.execSQL("DROP TABLE IF EXISTS " + "EventStatus"); 
      db.execSQL("DROP TABLE IF EXISTS " + "moduleDesc"); 
      onCreate(db); 
     } 
    } 

，我得到的是

 07-31 12:01:15.267: W/System.err(632): 
android.database.sqlite.SQLiteException: no such table: moduleDesc: , 
while compiling: insert into moduleDesc(deleteable,createable,updateable,name,label,labelfields,fields) 
values(?,?,?,?,?,?,?) 
    07-31 12:01:15.267: W/System.err(632): 
at android.database.sqlite.SQLiteCompiledSql.native_compile(Native Method) 
    07-31 12:01:15.267: W/System.err(632): 

at android.database.sqlite.SQLiteCompiledSql.compile(SQLiteCompiledSql.java:92) 
    07-31 12:01:15.267: W/System.err(632): 

at android.database.sqlite.SQLiteCompiledSql.<init>(SQLiteCompiledSql.java:65) 
    07-31 12:01:15.267: W/System.err(632): 

at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:83) 

谁能告诉错误我如何升级数据库

Answer 1

我相信你的问题可能是你有if语句循环。如果用户拥有应用程序的版本1或版本2，并且想要升级到最新版本（我相信是4），该怎么办？

在这种情况下，它将简单地通过if循环并进入最终else，它试图删除表moduleDesc，只有在用户计划从版本1或2升级到版本3时才创建该表。

因此，总之，检查您的if语句并迎合所有条件。

Answer 2

你不需要在mainfest文件中改变你可以改变你的SQL数据库类。检查下面的代码，你必须改变DATABASE_VERSION = 7;

public static final String TABLE_COMMENTS = "contacts"; 
public static final String COLUMN_ID = "_id"; 
public static final String COLUMN_COMMENT = "account"; 
public static final String COLUMN_USER_ID = "contactJids"; 
public static final String COLUMN_USER_NAME = "contactNames"; 

private static final String DATABASE_NAME = "contacts.db"; 
private static final int DATABASE_VERSION =7; 

// Database creation sql statement 
private static final String DATABASE_CREATE = "create table " 
     + TABLE_COMMENTS + "(" + COLUMN_ID  + " integer primary key autoincrement, " 
           + COLUMN_COMMENT + " text not null, " 
           + COLUMN_USER_ID + " text not null, " 
           + COLUMN_USER_NAME + " text not null);"; 

public MySQLiteHelper(Context context) { 
    super(context, DATABASE_NAME, null, DATABASE_VERSION); 
} 
@Override 
public void onCreate(SQLiteDatabase database) { 
    database.execSQL(DATABASE_CREATE); 
} 

@Override 
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
    Log.w(MySQLiteHelper.class.getName(), 
      "Upgrading database from version " + oldVersion + " to " 
        + newVersion + ", which will destroy all old data"); 
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_COMMENTS); 
    onCreate(db); 
} 

    }