||1: Creating good maps demands a lot of time and money. ||2: Google has taken about eight years to build up its expertise: it has sent cars along the world’s roads and maintains a fleet of aeroplanes. ||3: Nokia’s mappers (who have been issuing reminders that they offer web-based maps for the iPhone) have a longer pedigree still. ||4: Apple, which has bought three mapmaking firms in the past three years and is supplied with data by TomTom, a Dutch company, has plenty of money to throw at catching up on maps, but it will take time. ||5: "Over two to three years," estimates Martin Garner of CCS Insight, a research firm, "Apple can get up to good enough."

||1:编写优秀的地图应用需要很长的时间和大量的资金。||2:谷歌研发了八年左右才具备这方面的专长：该公司往世界各地派遣了道路勘测车辆，并且保有一批用于地图测绘的飞机。||3: 诺基亚的地图绘制历史更是源远流长（其制图人一直在提醒用户：诺基亚为 iPhone 提供基于网页的地图应用）。 ||4: 苹果在过去的三年里收购了三家地图绘制公司，还有荷兰公司 TomTom 为其提供数据。要想在地图应用方面后来居上，苹果有足够的资金；但这毕竟需要时间。 ||5: 研究公司 CCS Insight 的 Martin Garner 估计："再过两到三年，苹果的地图应用就能达到一个不错的水准。"

The mappers ’ aim is to find out how nerve cells collaborate to process information.

制图者的目标是找出神经细胞是如何共同处理信息的。

Rails migrations allow direct SQL for unsupported extensions (such as stored procedures or constraints), while some ORM mappers don’t.

Rails迁移允许对不支持的扩展（例如存储过程或约束）直接使用SQL，而有些ORM映射器不支持。

Object relational mappers are heavyweight for certain types of applications.

对象关系映射程序对于某些类型的应用程序是重量级的。

Your Rails 3 application can use one of a number of compatible object-relational mappers (ORM), template engines, and test frameworks.

您的Rails3应用程序可以使用一些兼容的对象关系映射器（ORM）、模板引擎和测试框架。

Instead of using a Reader class that reads an XML configuration, you can add the mappers to the Configuration object, as shown in Listing 9.

我们不再使用Reader类来读取XML配置，而是要向Configuration对象添加映射程序，如清单9所示。