感谢您澄清onUpgrade()将不支持删除/删除语句@Pentium 10
对于那些你想知道的确切时刻谁当onUpgrade()被调用,它是一个过程调用getReadableDatabase()或getWriteableDatabase()。
对于那些不清楚如何确保它被触发的答案是:当提供给SqLiteOpenHelper的构造函数的数据库版本更新为时,会触发它。下面是一个例子
public class dbSchemaHelper extends SQLiteOpenHelper {
private String sql;
private final String D_TAG = "FundExpense";
//update this to get onUpgrade() method of sqliteopenhelper class called
static final int DB_VERSION = 2;
static final String DB_NAME = "fundExpenseManager";
public dbSchemaHelper(Context context) {
super(context, DB_NAME, null, DB_VERSION);
// TODO Auto-generated constructor stub
}
现在... onUpgrade()
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
sql = "ALTER TABLE " + fundExpenseSchema.Expense.TABLE_NAME + " ADD COLUMN " + fundExpenseSchema.Expense.FUNDID + " INTEGER";
arg0.execSQL(sql);
}
你知道迈克,它已经过了一年。你真的应该接受其中一个答案 – Noah 2011-10-18 13:42:32
最后看到:09年9月7日在17:35 – 2012-12-05 06:34:41
年,但迈克不要叫'onUpgrade()' – 2013-08-01 06:52:15