Android SQLiteHelper with auto upgrade and downgrade

SQLiteHelper.java

private class SQLiteHelper extends SQLiteOpenHelper {
	public DatabaseOperations(Context context) {
		super(context, DatabaseSchemas.DATABASE_NAME, null, DatabaseSchemas.DATABASE_VERSION);
	}

	public void onCreate(SQLiteDatabase db) {
		//Create all tables
		db.execSQL(DatabaseSchemas.Table.CREATION_SQL);
	}

	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		//Make all table names in a List. This saves a lot of effort.
		List<String> tableList = new ArrayList<>();
		Cursor c = db.query(
				"sqlite_master",
				new String[]{
						"name"
				},
				"type = ? AND name != ?",
				new String[]{
						"table",
						"android_metadata"
				}, null, null, "name", null);
		if (c != null) {
			if (c.moveToFirst()) {
				while (! c.isAfterLast()) {
					tableList.add(c.getString(c.getColumnIndex("name")));
					c.moveToNext();
				}
			}
			c.close();
		}
		//backup the content of old database.
		for (int i = 0; i < tableList.size(); i++) {
			db.execSQL("ALTER TABLE " + tableList.get(i) + " RENAME TO " + "old" + tableList.get(i));
		}
		//create new tables
		db.execSQL(DatabaseSchemas.Table.CREATION_SQL);
		//exclude any tables that no longer present
		//WARNING: possible data loss
		List<String> ntableList = new ArrayList<>();
		c = db.query(
				"sqlite_master",
				new String[]{
						"name"
				},
				"type = ? AND name != ? AND name NOT LIKE ?",
				new String[]{
						"table",
						"android_metadata",
						"old%"
				}, null, null, "name", null);
		if (c != null) {
			if (c.moveToFirst()) {
				while (! c.isAfterLast()) {
					ntableList.add(c.getString(c.getColumnIndex("name")));
					c.moveToNext();
				}
			}
			c.close();
		}
		tableList.retainAll(ntableList);
		//move data into new tables
		for (int i = 0; i < tableList.size(); i++) {
			List<String> columns = GetColumns(db, "old" + tableList.get(i));
			columns.retainAll(GetColumns(db, tableList.get(i)));
			String cols = TextUtils.join(",", columns);
			db.execSQL(String.format("INSERT INTO %s (%s) SELECT %s FROM old%s", tableList.get(i), cols, cols, tableList.get(i)));
			db.execSQL("DROP TABLE " + "old" + tableList.get(i));
		}


	}

	@Override
	public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		//basically the same stuff, so we just call onUpgrade here
		onUpgrade(db, oldVersion, newVersion);
	}


	private List<String> GetColumns(SQLiteDatabase db, String tableName) {
		List<String> columns = null;
		Cursor c = null;
		try {
			c = db.query(tableName, null, null, null, null, null, null);
			if (c != null) {
				columns = new ArrayList<String>(Arrays.asList(c.getColumnNames()));
			}
		} catch (Exception e) {
			Log.e(tableName, e.getMessage(), e);
			e.printStackTrace();
		} finally {
			if (c != null)
				c.close();
		}
		return columns;
	}

}