1. SSIS package is a collection of connections, control flow elements, data flow elements, event handlers and variables.
2. SSIS package can be built using Visual Studio 2005 by design mode by dragging and droping controls or programatically by adding the referece of SSIS components.
3. SSIS package can be stored in File System, SQL Server, SSIS package store.
4. Package is a unit of work that is retrived, executed and saved, either manually or on scheduled intervals of time or on specific day and time.
5. It is vast and lots of features involved, reliable and configurable.
6. Other major objects used with package to support on runtime are configuration, Logging and Event Handlers.
Event Handlers : It is an work flow that runs in response to the events raised in package, task or container.
Configuration : It is a set of property values used by the package, it enables the package to be customized.
Logging : It is a collection if information about the package, that is collected when it runs.
Variables : Supports system variables & user defined variables. it can be used in expression, script and configuration. each variable have scope depends its creation.