Marks Table Sub-system
The main page for this sub-system is shown in Figure 17. This page is essentially the same as that of the Users Table Sub-system, only differing in the table displayed, and thus the number and names of the fields, and in the table-specific operations. The same comments on the record store and on the Section called Selecting records apply to this page. Note that the number of entries in the marks table can get very large, as shown in the example, and the ability to restrict the number of records shown was developed to prevent the long transfer times when all the records of a large table are displayed.
It should be noted that this table is not expected to be edited as the records in this table are added automatically as users answer questions. It should also be noted that there are potential problems in the current system if an attempt is made to modify the marks table, while users are accessing the or have access to the system. The marks sub-system reads the marks records into the record store and any changes are made to these records. Any additions to the marks table from students answerng questions after the table has been read are only appended to the marks table and are not added to the record store. This means that there is potential for marks to be lost when the record store overwrites the table.
 | Since it is not envisaged that editing of the marks table is a signifcant activity, no mechanisms have yet been decided upon to remove this potential point of failure. |
Common Table Functions
The common table functions for the page are listed below and details can be obtained from the section on the username password table sub-system.
Record Display Functions
| changeDisplay |
| displayAll |
| hideAll |
Paste Functions>
See the Section called Paste Commands and section on Cut Buffers
| Paste-Before |
| Paste-After |
| Paste-Over |
Load, Store and Save Functions
| Load-from-File |
| Save-to-File |
| Save-to-Database |
Other Functions
| Sort |
| Close |
| Refresh |
| Show-Cut-buffer |
| Clear-Cut-buffer |
Table Specific Functions
AddMarksFrom File Function
There are occasional instances in my environment, when connectivity to the database is lost, and marks fail to be recorded in the marks table of the databas. These "lost" marks are recorded in the system log file along with an error message. If these error messages are copied into a file, then this file can be read and parsed by this function to extract the marks from the error messages are stored in records which are appended to the record store behind the rest of the table records. This allows these marks to be added back into the marks table by saving the record store with the Save-to-Database function. This action must occur when users are not accessing the system: see marks table update warning.
On clicking on the "AddMarksFromFile" link, the marks display is replaced a file selector for (Figure 18that allows the identification of the file containing the error messages with the lost marks : see Figure 19 to see an example of the error messages.
