在PHP中，高效的数据库操作通常涉及以下几个方面：

1. **选择合适的数据库抽象层（DAL）**：
- 可以使用PHP自带的`PDO`（PHP Data Objects）或者`MySQLi`扩展来操作数据库。它们提供了更安全、更快的接口来执行SQL语句。
- 如果你在开发大型应用，可以考虑使用ORM（对象关系映射）工具，如`Doctrine`、`Eloquent`（Laravel的一部分）或`CakePHP`的`ORM`，它们可以简化数据库操作，并提供额外的功能，如数据映射和查询构建。

2. **使用预处理语句和绑定参数**：
- 使用`PDO`或`MySQLi`时，应该始终使用预处理语句和绑定参数来防止SQL注入攻击。这也能提高代码的可读性和可维护性。

3. **优化SQL语句**：
- 确保SQL语句是高效的，可以通过分析和使用索引来优化查询。避免使用`SELECT *`，而是明确指定需要的列。
- 使用`JOIN`而不是子查询，通常JOIN操作效率更高。
- 使用`EXPLAIN`来分析SQL语句的执行计划，找出性能瓶颈。

4. **使用事务**：
- 对于需要保持数据一致性的操作，可以使用事务来确保一组操作要么全部执行，要么全部不执行。

5. **缓存策略**：
- 对于频繁访问的数据，可以使用缓存来减少数据库的访问次数。可以使用内存缓存（如`APC`、`Memcached`或`Redis`）或者数据库自身的缓存机制。

6. **错误处理**：
- 正确处理数据库操作中的错误，避免应用程序崩溃。使用`try...catch`语句来捕捉异常，并提供合理的错误信息。

7. **性能监控和日志记录**：
- 定期监控数据库的性能，记录执行时间较长的查询，以便进一步优化。

8. **使用数据库特有的功能**：
- 了解并使用数据库特有的功能，如MySQL的````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````````