Macromedia ColdFusion MX provides several variable scopes in which data persists past the life of a single request. These are the Client, Application, Session, and Server scopes. These scopes let you save data over time and share data between pages and even applications. (This chapter refers to these scopes as persistent scopes.) In particular, you can use the Client and Session scopes to maintain information about a user across multiple requests.
ColdFusion MX lets you lock access to sections of code to ensure that ColdFusion does not attempt to run the code, or access the data that it uses, simultaneously or in an unpredictable order. This locking feature is important for ensuring the consistency of all shared data, including data in external sources in addition to data in persistent scopes.
This chapter describes how to use persistent scopes to develop an application and how to use locking to ensure data consistency.