Android sqlite 数据库在java代码中的增删改查

 private void queryPerson(PersonSQLiteOpenHelper personSQLiteOpenHelper) {        SQLiteDatabase sqLiteDatabase = personSQLiteOpenHelper.getReadableDatabase();        Cursor cursor = sqLiteDatabase.query("person", new String[]{"id", "name", "age"}, null, null, null, null, null, null);        while(cursor.moveToNext()) {            int id = cursor.getInt(cursor.getColumnIndex("id"));            String name = cursor.getString(cursor.getColumnIndex("name"));            int age = cursor.getInt(cursor.getColumnIndex("age"));            System.out.println("id = " + id);            System.out.println("name = " + name);            System.out.println("age = " + age);            System.out.println("————————————————————————————————");        }    }    private void deletePerson(PersonSQLiteOpenHelper personSQLiteOpenHelper) {        SQLiteDatabase sqLiteDatabase = personSQLiteOpenHelper.getWritableDatabase();        sqLiteDatabase.delete("person", "id=?", new String[]{"2"});        sqLiteDatabase.close();    }    /**     * 模拟事务     */    private void transactionTest(){        SQLiteDatabase sqLiteDatabase = SQLiteDatabase.openOrCreateDatabase("/data/data/com.wuyou.sqlitetest/databases/person.db",null);        //首先打开一个事务        sqLiteDatabase.beginTransaction();        try {            sqLiteDatabase.execSQL("update person set age = 44 where id=1");            //模拟事务失败            String x = null;            x.equals("");            sqLiteDatabase.execSQL("update person set age = 11 where id=4");            //标记事务成功            sqLiteDatabase.setTransactionSuccessful();        }catch (Exception e){            System.out.println("处理事务的时候出现异常 ");        } finally {            //最终标记事务完成            sqLiteDatabase.endTransaction();            sqLiteDatabase.close();        }    }    /**     * 添加一个人     *     * @param sqLiteOpenHelper     */    public void addPerson(SQLiteOpenHelper sqLiteOpenHelper) {        SQLiteDatabase database = sqLiteOpenHelper.getWritableDatabase();        ContentValues contentValues = new ContentValues();        contentValues.put("name", "wuyou");        contentValues.put("age", 21);        database.insert("person", null, contentValues);        database.close();    }    public void updatePerson(SQLiteOpenHelper sqLiteOpenHelper) {        SQLiteDatabase database = sqLiteOpenHelper.getWritableDatabase();        ContentValues contentValues = new ContentValues();        contentValues.put("name", "zhangsan");        contentValues.put("age", 33);        database.update("person", contentValues, "id=?", new String[]{"1"});        database.close();    }
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