Android -在哪里添加PRAGMA synchronous=OFF

Question

我有一个创建数据库和插入数据到表中的代码，当我的应用程序第一次安装时。我想添加"PRAGMA synchronous=OFF“以提高插入速度。在下面的代码中，我应该在哪里添加"PRAGMA synchronous=OFF“？

public class DataBaseHelper extends SQLiteOpenHelper {
    private static final String DATABASE_NAME = "scheduleDB";
    private static final int DB_VERSION = 1;

    Context context;

    public DataBaseHelper(Context context) {
        super(context, DATABASE_NAME, null, DB_VERSION);
        this.context = context;
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        try {                
            db.execSQL("CREATE TABLE time (id INTEGER PRIMARY KEY AUTOINCREMENT, arrival VARCHAR(10), departure VARCHAR(10));");    
            insertTime(db,"city");
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        try {
            onCreate(db);
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }


    public void insertTime(SQLiteDatabase database, String table) {
        BufferedReader br = null;
        String line;

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
            database.beginTransactionNonExclusive();
        } else {
            database.beginTransaction();
        }

        try {                
            br = new BufferedReader(new InputStreamReader(context.getAssets().open("time.txt")));
            while ((line = br.readLine()) != null) {                    
                String query = "INSERT INTO "+table+" (arrival, departure) VALUES (?,?)";
                SQLiteStatement statement = database.compileStatement(query);

                String[] time = line.split(",");

                for(int i = 1, n = time.length; i < n; i+=2) { 
                    statement.clearBindings();
                    statement.bindString(1,time[i-1]);//arrival
                    statement.bindString(2,time[i]);//departure
                    statement.execute();
                }
            }
            br.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            database.setTransactionSuccessful();
            database.endTransaction();
            if (br != null) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}