Android 升级 SQLite - 表未修改

Question

我在升级 SQLite 时遇到问题。我正在使用 SQLiteOpenHelper，我只是添加了一列，更改了数据库版本，但问题是，新列没有显示（没有制作）。据我所见，正确调用了 OnCreate 和 OnUpgrade ，但我不知道为什么不制作新表。我只在表“smeri”中添加了最后一列“在线”

public class DatabaseHandler extends SQLiteOpenHelper {

private static final int DATABASE_VERSION = 16;

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

// Contacts table name
private static final String TABLE_NAME_mainpoints = "mainpoints";
private static final String TABLE_NAME_smeri = "smeri";
private static final String TABLE_NAME_povezave = "povezave";

// Contacts Table Columns names
private static final String KEY1_ID = "ID";
private static final String KEY1_X = "X";
private static final String KEY1_Y = "Y";

private static final String KEY2_ID = "ID";
private static final String KEY2_ime = "Ime";
private static final String KEY2_tezavnost = "Tezavnost";
private static final String KEY2_opis = "Opis";
private static final String KEY2_avtor = "Avtor";
private static final String KEY2_datum = "Datum";
private static final String KEY2_online = "Online";

private static final String KEY3_IDsmeri = "IDsmeri";
private static final String KEY3_IDtocke = "IDtocke";
private static final String KEY3_vrstaTocke = "vrstaTocke";

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

@Override
public void onCreate(SQLiteDatabase db) {
    Log.e("log_tag", "ON CREATE!!!!!!!!");

    String CREATE_mainpoints_TABLE = "CREATE TABLE " + TABLE_NAME_mainpoints + "("
            + KEY1_ID + " INTEGER PRIMARY KEY,"
            + KEY1_X + " INTEGER,"
            + KEY1_Y + " INTEGER" + ")";
    db.execSQL(CREATE_mainpoints_TABLE);


    String CREATE_smeri_TABLE = "CREATE TABLE " + TABLE_NAME_smeri + "("
            + KEY2_ID + " INTEGER PRIMARY KEY,"
            + KEY2_ime + " TEXT,"
            + KEY2_tezavnost + " TEXT,"
            + KEY2_opis + " TEXT,"
            + KEY2_avtor + " TEXT,"
            + KEY2_datum + " TEXT,"
            + KEY2_online + " INTEGER" + ")";
    Log.e("log_tag", ""+CREATE_smeri_TABLE);
    db.execSQL(CREATE_smeri_TABLE);

    String CREATE_povezave_TABLE = "CREATE TABLE " + TABLE_NAME_povezave + "("
            + KEY3_IDsmeri + " INTEGER,"
            + KEY3_IDtocke + " INTEGER,"
            + KEY3_vrstaTocke + " INTEGER " + ")";
    db.execSQL(CREATE_povezave_TABLE);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    // Drop older table if existed
    Log.e("log_tag", "ON UPGRADE!!!!!!!!");
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME_mainpoints);
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME_smeri);
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME_povezave);

    // Create tables again
    onCreate(db);
}

Answer 1

使用此代码：

 public class DatabaseHandler extends SQLiteOpenHelper {

        private static final int DATABASE_VERSION = 16;

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

        // Contacts table name
        private static final String TABLE_NAME_mainpoints = "mainpoints";
        private static final String TABLE_NAME_smeri = "smeri";
        private static final String TABLE_NAME_povezave = "povezave";

        // Contacts Table Columns names
        private static final String KEY1_ID = "ID";
        private static final String KEY1_X = "X";
        private static final String KEY1_Y = "Y";

        private static final String KEY2_ID = "ID";
        private static final String KEY2_ime = "Ime";
        private static final String KEY2_tezavnost = "Tezavnost";
        private static final String KEY2_opis = "Opis";
        private static final String KEY2_avtor = "Avtor";
        private static final String KEY2_datum = "Datum";
        private static final String KEY2_online = "Online";

        private static final String KEY3_IDsmeri = "IDsmeri";
        private static final String KEY3_IDtocke = "IDtocke";
        private static final String KEY3_vrstaTocke = "vrstaTocke";

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

        @Override
        public void onCreate(SQLiteDatabase db) {
            Log.e("log_tag", "ON CREATE!!!!!!!!");

            String CREATE_mainpoints_TABLE = "CREATE TABLE " + TABLE_NAME_mainpoints + "("
                    + KEY1_ID + " INTEGER PRIMARY KEY,"
                    + KEY1_X + " INTEGER,"
                    + KEY1_Y + " INTEGER" + ")";
            db.execSQL(CREATE_mainpoints_TABLE);


            String CREATE_smeri_TABLE = "CREATE TABLE " + TABLE_NAME_smeri + "("
                    + KEY2_ID + " INTEGER PRIMARY KEY,"
                    + KEY2_ime + " TEXT,"
                    + KEY2_tezavnost + " TEXT,"
                    + KEY2_opis + " TEXT,"
                    + KEY2_avtor + " TEXT,"
                    + KEY2_datum + " TEXT,"
                    + KEY2_online + " INTEGER" + ")";
            Log.e("log_tag", ""+CREATE_smeri_TABLE);
            db.execSQL(CREATE_smeri_TABLE);

            String CREATE_povezave_TABLE = "CREATE TABLE " + TABLE_NAME_povezave + "("
                    + KEY3_IDsmeri + " INTEGER,"
                    + KEY3_IDtocke + " INTEGER,"
                    + KEY3_vrstaTocke + " INTEGER " + ")";
            db.execSQL(CREATE_povezave_TABLE);
        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            // Drop older table if existed
            try{
                if(oldVersion<16){
                    db.execSQL("ALTER TABLE " + TABLE_NAME_smeri +" ADD column "+KEY2_online+ " INTEGER "); 
                }   
            }catch(SQLException e){
                e.printStackTrace();
            }

            }
        }

Answer 2

确保将表名放在引号中

db.execSQL("DROP TABLE IF EXISTS '" + TABLE_NAME_mainpoints +"'");

Answer 3

你可以试试加栏

db.execSQL("alter table smeri add column Online int");