Salesforce.com is a software-as-a-service (SaaS) cloud solutions provider.Salesforce.com offers many cloud based products like, Sales Cloud, Service Cloud, Force.com and many more. Force.com is a platform offered by Salesforce.com to develop and deploy custom enterprise applications in cloud.
A typical enterprise application can be divided into three layers, data model, business logic and user interface. Force.com platform has various components which are the building blocks of each layer. These components are again divided into two sub categories, declarative and programmatic. The declarative component means using point and click in browser to build applications. The programmatic component needs coding to develop applications.
The Force.com data model layer components are, objects, fields, relationships, webservices API, metadata API. The workflow, validation rules, approval processes, controllers, Force.com code and Apex are from business logic layer. The user interface layer consists of applications, tabs, page layouts, record types, Force.com pages, Sites and Visualforce.
Force.com also offers point and click development tools to build custom apps for smart phones and tablets without learning any mobile programming language. This solution is called, Salesforce Mobile.