DB Staging is a Staging component that loads incoming data streams into a single staging area. DB Staging buffers all incoming data, then creates an outgoing data stream, which represents the result set of a given select statement.
You can create staging tables based on the OUT-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 a given size.
You can use staging components to perform sorts or aggregations by using ORDER BY or GROUP BY clauses in the Query property. Data from heterogeneous sources can be joined by loading them into multiple tables of the staging database. You can also use the DB Staging component to create an intermediate image of the transformation for further inspection or processing.
In simulation, the DB Staging component first retrieves
all data from the original data sources, then acts as a new data
source for subsequent components. The component allows the Read
Block Size value of the original source components to be overwritten.
