User`s guide

CHAPTER 6 Components
User’s Guide 107
Staging components
DB Staging component
The DB Staging component loads the incoming data streams into a staging
area. The data is buffered until the incoming data stream has finished, Then an
outgoing data stream, which is the result set of a given
SELECT statement, is
created. The staging tables can be created based on the output port structure of
the preceding component. Although many transformation components are
designed to work on a record-by-record basis, the staging component works in
two phases:
• Phase 1: Collect ALL records from the preceding components.
• Phase 2: Run the query and provide the records of the result set in blocks
of given size.
Use this component to stage your transformation data in a dedicated area to
perform aggregation or joins on data from heterogeneous sources.
You can use staging components to perform sorts or aggregations on formerly
unordered records by using
ORDER BY or GROUP BY clauses in the Query
property.
You could also use this component for creating an intermediate image of the
transformation for further inspection or processing.
❖ To use the staging component
1 Add the component to the project and connect the ports to adjacent
components.
2 To add input streams to the DB Staging component, you can drop
connections from the data providing component on the staging
component. The ports are automatically created by the component.
3 Enter the Connection Parameters as described in “Entering database
connection parameters” on page 71.
4 Create the staging tables. If the staging tables you are going to use already
exist, go to step 6.