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Record Validation

Mihai Radulescu
Ranch Hand

Joined: Sep 18, 2003
Posts: 916


My FileHanlder - the class which is responsible for the physical access to the database file - has a record validation mechanism. In this way I ensure that the new added (or modified record) follows a specified format.
The check is done according with my specification, more precisely
1.the arrays must have 7 elements(fields)
2.the smoking field must be Y or N
3.the date filed must be in yyyy/mm/dd
4.Customer field must be a an 8 digit number

Is this to less ? It is enough ?

Regards M

Tim Anlauf

Joined: Oct 11, 2006
Posts: 22
I passed with the solution that all data could be stored into file. I just trimmed the lenght of the Strings to the specified lenght of db file. If the String lenght is lower that possible I filled up with spaces.
Mihai Radulescu
Ranch Hand

Joined: Sep 18, 2003
Posts: 916

Hi Tim,

Congratulation for your exam.

I also provide the trim/pad function like default but extra I provides a possibility to check if the new added records (or the modified one) follows a specified format. This is feature is toggable.
The format check can spare a lot of problems - just think what happen in multi user mode if a user change the content for a record - most precisely the date field with a value which is not a data (it can not be passed like a date), after this you try to apply the 48 Hours rule (on all the record and explicit on the record with the wrong date). That are my arguments.

Regards M.
Tim Anlauf

Joined: Oct 11, 2006
Posts: 22
Yes you are right.

But for this application it is only needed to book a record. You could be sure that only the customer id will be changed.

In my "first life" projects I preffer to do a data validation at the deepest part of my application. Before the data is persisted. So data could never be stored in a corrupted way.

For SCJD it is also possible to do a GUI validation.

Concerning the 24h rule:
I implemented it so that records which aren't bookable any more are rendered in red font color. This mechanismn is "failure save", if a date couln't be parsed it is rendered in red too.
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