Force.com as a Platform
Force.com is different from other PaaS solutions in its focus on business applications. Force.com is a part of Salesforce.com, which started as a SaaS customer relationship management (CRM) vendor. But Force.com is not CRM. It provides the infrastructure commonly needed for any business application, customizable for the unique requirements of each business through a combination of code and configuration. This infrastructure is delivered to you as a service on the Internet.
Because you are reading this book, you have probably developed a few business applications in your time. Consider the features you implemented and reimplemented in multiple applications, the unglamorous plumbing, wiring, and foundation work. Some examples are security, user identity, logging, profiling, integration, data storage, transactions, workflow, collaboration, and reporting. This infrastructure is essential to your applications but expensive to develop and maintain. Business application developers do not code their own relational database kernels, windowing systems, or operating systems. This is basic infrastructure, acquired from software vendors or the open source community and then configured to meet user requirements. What if you could do the same for your application infrastructure? This is the premise of Force.com.
The following subsections list differentiating architectural features of Force.com with brief descriptions.
Multitenancy
Multitenancy is an abstract concept, an implementation detail of Force.com, but one with tangible benefits for developers. Figure 1.1 shows a conceptual view of multitenancy. Customers access shared infrastructure, with metadata and data stored in the same logical database.
The multitenant architecture of Force.com consists of the following features:
Shared infrastructure—All customers (or tenants) of Force.com share the same infrastructure. They are assigned an independent logical environment within the Force.com platform.
At first, some might be uncomfortable with the thought of handing their data to a third party where it is comingled with that of competitors. Salesforce’s whitepaper on its multitenant technology includes the technical details of how it works and why your data is safe from loss or spontaneous appearance to unauthorized parties.
Single version—Only one version of the Force.com platform is in production. The same platform is used to deliver applications of all sizes and shapes, used by 1 to 100,000 users, running everything from dog-grooming businesses to the Japanese national post office.
Continuous, zero-cost improvements—When Force.com is upgraded to include new features or bug fixes, the upgrade is enabled in every customer’s logical environment with zero to minimal effort required.
Salesforce can roll out new releases with confidence because it maintains a single version of its infrastructure and can achieve broad test coverage by leveraging tests, code, and configurations from its production environment. Salesforce’s internal process for regression testing the platform using its customers has a name fitting its aggressive role: The Hammer. You, the customer, are helping maintain and improve Force.com in a systematic, measurable way as a side effect of simply using it. This deep feedback loop between Force.com and its users is something impractical to achieve with on-premises software. Additionally, detailed communication of release schedules and contents, opt-in features, and the critical update system for backward-incompatible changes help keep customers and developers well informed and applications stable.
Note
Find more details on “The Hammer” at http://blogs.developerforce.com/engineering/2013/05/here-comes-the-hammer.html.
Relational Database
The heart of Force.com is the relational database provided as a service. The relational database is the most well understood and widely used way to store and manage business data. Business applications typically require reporting, transactional integrity, summarization, and structured search, and implementing those on nonrelational data stores requires significant effort. Force.com provides a relational database to each tenant, one that is tightly integrated with every other feature of the platform. There are no Oracle licenses to purchase, no tablespaces to configure, no Java Database Connectivity (JDBC) drivers to install, no Object-Relational Mapping (ORM) to wrangle, no Data Definition Language (DDL) to write, no queries to optimize, and no replication and backup strategies to implement. Force.com takes care of all these tasks.
Application Services
Force.com provides many of the common services needed for modern business application development. These are the services you might have built or integrated repeatedly in your past development projects. They include logging, transaction processing, validation, workflow, email, integration, testing, reporting, and user interface.
These services are highly customizable with and without writing code. Although each service can be valued as an individual unit of functionality, their unification offers tremendous value. All the features of Force.com are designed, built, and maintained by a single responsible party, Salesforce. Salesforce provides documentation for these features as well as support staff on call, training and certification classes, and accountability to its customers for keeping things running smoothly. This is in contrast to many software projects that end up as a patchwork of open source, best-of-breed tools and libraries glued together by you, the developer, asked to do more with fewer people, shorter timelines, and cheaper, often unsupported tools.
Declarative Metadata
Almost every customization configured or coded within Force.com is readily available as simple Extensible Markup Language (XML) with a documented schema. At any point in time, you can ask Force.com for this metadata via a set of Web services. The metadata can be used to configure an identical environment or managed with your corporate standard source control system. It is also helpful for troubleshooting, allowing you to visually compare the state of two environments. Although a few features of Force.com are not available in this declarative metadata form, Salesforce’s stated product direction is to provide full coverage.
Programming Language
Force.com has its own programming language, called Apex. It allows developers to script interactions with other platform features, including the user interface. Its syntax is a blend of Java and database-stored procedure languages like Transact-SQL (T-SQL) and can be written using a Web browser or a plug-in to the Eclipse Integrated Development Environment (IDE).
Other platforms take a different approach. Google’s App Engine simultaneously restricts and extends existing languages such as Python so that they play nicely in Google’s PaaS environment. This offers obvious benefits, such as leveraging the development community, ease of migration, and skills preservation. One way to understand Apex is as a domain-specific language. Force.com is not a general-purpose computing platform to run any Java or C# program you want to run. Apex is kept intentionally minimalistic, designed with only the needs of Force.com developers in mind, built within the controlled environment of Salesforce Research and Development. Although it won’t solve every programming problem, Apex’s specialized nature leads to some advantages in learning curve, code conciseness, ease of refactoring, and ongoing maintenance costs.