Interaction between the application, images, the database, and the SDB
The following diagram illustrates the flow of data at different stages of your use of Enterprise Timetabler.
If no Enterprise Foundation applications are running (specifically: , Enterprise Course Planner, or Enterprise Desktop Reference Data Manager), and you start Enterprise Timetabler:
- If an image that corresponds to the SDB is not present on the workstation hard drive, the hot image is downloaded from the server (1) then loaded into memory (2). A corresponding database is created on the hard drive.
- Else, the image that is present on the hard drive is loaded into memory (2).
- A backup of the database is created (3).
When you perform an action that reads data, the data is read from the database on the workstation hard drive (4).
When you perform an action that changes data:
- If you directly change data, the change is made in the database (5) and the image in memory (6). For example, if you remove a module from a student set in Enterprise Course Planner, or unallocate a student set from an activity in , you have directly changed data. Or, your action might be to run a function that changes data, such as the Schedule function in ; the function changes data in the image in memory.
- If data in the image changes as a consequence of your action, Enterprise DataSync copies the changes from the image in memory to the database (7). For example, when a module is removed from a student set, the student set is automatically unallocated from all the activities of that module.
Note: If this synchronisation of the image and the database fails, Enterprise Timetabler displays an exclamation mark in the bottom corner of the application window. If you expected changes in the image to synchronise but they have not, click Synchronise CE database with local S+ image .
When you use the Writeback function, data is sent from the image in memory to the SDB (8).
When you use the Refresh function, changes made by other users are received from the SDB (9).
If Enterprise Timetabler is the only Enterprise Foundation application that is open, and you exit the application, one of the following actions occurs. After the action completes, the data in the database and the image on the hard drive is synchronised; the Enterprise Foundation application that starts next can use the database and load the image into memory.
- If you select Yes for the Do you wish to save a local copy of the data for use at your next session on this machine? option, the image in memory replaces the image on the hard drive (10).
- If you select No, the image in memory is deleted. The backup of the database replaces the database (11).