Development Guidelines and Procedures
Advanced system development utilizing Powerhouse products often mandates the access of multiple databases or data files from one Powerhouse dictionary. To facilitate inter-system development dictionary source files must be separated to allow multiple database Powerhouse dictionaries to be created from the same source files used to create single database Powerhouse dictionaries. When such a dictionary exists each IT staff member is responsibile to ensure that updates to database and data file structures are communicated to those who need to know. Refer to the naming conventions outlined above for more information.
System InterfacesCarefully scrutinize on-line requirements before choosing the type of interface to be used and discuss this interface with your manager prior to design.
- Type 1 - Separate systems are interfaced via the dictionary of a subfile. This interface should be used when multiple offices must maintain jurisdiction and a batch interface will suffice. A change in one system will have minimal impact on the other. A change in the Powerhouse dictionary of the interfaced system will not necessarily require recompilation of the interfacing system's Powerhouse dictionary. If the system is very small and could be easily adopted into the main Powerhouse dictionary it still should be separate if on-line access does not present a problem.
- Type 2 - A new system is wholly incorporated into the Powerhouse dictionary of an existing system. This interface permits complete system incorporation. The disadvantage is that the system becomes larger with responsibility for the maintenance of the Powerhouse dictionary ultimately residing with the IT staff member of the larger system. Use this when on-line interfaces are required. In most cases one office will maintain jurisdiction over the system. As system integration continues to increase this method will become more prevalent. The proper use of system codes on data sets (tables) and data items (columns) are absolutely necessary for this approach to be successful.
- Type 3 - A portion of one Powerhouse dictionary is duplicated in a second system. This interface is a last resort. Simultaneous on-line access to both systems are required. The interface cannot be limited to one small program. Multiple offices maintain authority for separate functions. A diagram of the datasets used from the interfaced system must be included in the schema diagram of the interfacing system. This diagram must be included with the interfaced system's documentation and listed in the system book of the interfaced system. A Robot listing of affected programs will be supplied to the IT staff member of the interfacing system whenever dictionary changes are made. Quick screens should be used to move the user from system to system (resist the temptation to supply data from both systems on the same screen, especially to update) to enforce security of interfaced systems. When possible use existing screens rather than create new ones, or at least create these new ones as part of the interfaced system. Manager approval is required for this type.
Communication RequirementsContact the IT staff member of all interfacing systems when:
- database password(s) changes,
- interfaced dataset(s) record size is expanded, or
- definition of interfaced data item(s) changes.