The destination application and process that uses the source data must also be understood. In our scenario, how often is there a need for analysis and custom reporting on the desktop? Are there times of the year (preceding quarterly reports, for example) when the demand for the latest data from sales or manufacturing is greater?
A decision needs to be made on how frequently data will be moved and transformed from the data source (IBM DB2 database tables) to the destination (SQL Server database tables). At what intervals do reports need to be generated? A common scenario is that this data movement happens once a day or once a week, usually occurring in the middle of the night or on weekends when the core business applications are shut down and the database is not involved with interactive use.
The frequency of data transfer can also be limited by the amount of data to move and transform and the amount of time this will take. In some organizations, the core business data may not be accessible from other applications for non-technical reasons during normal operating hours. System administrators may decide that concerns about the impact on response times for interactive users, database stability, and reliability issues justify making the DB2 or other RDBMS data off limits during normal or peak operating hours. Under these circumstances, data transfers may only be allowed when the critical interactive business applications are quiescent or off line for maintenance and batch operations.
It is often valuable to be able to support special one-time requests for analyzing the latest information for use in some special meeting and report. This may force data transfers to occur under less than ideal times.