Many middleware programs,
such as Siebel, have their own proprietary database on which they have built their
application. In such cases, the incoming data has to be properly matched to the target
database schema. Since the middleware uses data from different database products
(MS SQL Server, Oracle, etc.), the ETL process has to step up to this task. In fact SSIS
is best suited for this task, as a plethora of data access methods are provided. You
will see an example of data going between SQL Server and an Oracle database in
Chapter 13.
Chapter 1
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Objects Used in SSIS
SSIS is governed by an object model. Working with SSIS requires a clear
understanding of this model. This section describes some important and salient
features of the object model. The objects used in building an Integrated Services
Package, and the manner in which they work together in the package workflow, are
as follows:
Package: This contains all objects in a single unit of work that can be
retrieved, executed, or saved at one of several locations.
Control Flow: These elements consist of tasks and containers, and take care
of the work flow by preparing data, and arranging for interaction with other
processes, but the ordering of tasks is controlled by precedence constraints,
which is another important constituent of flow control.
Data Flow: These components consist of a source (adapter) and destination
(adapter) for the data, as well as any data transformation that may be
needed.
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