Re: [Bodington-developers] access log

[Matthew B. <mat...@ou...>]

Jon Maber wrote:
> True, so public static Event findEvent( String where ) etc. will return
>> Events for that sub class and casting will identify event_codes for 
>> that type. But what if we use JDBC to query events table - we don't 
>> have object info? Are you providing WS or other API for external 
>> queries?
>>   
> 
> PersistentObject 101....
> 
> 
> The object oriented nature of the Bodington data store is implemented 
> like this....
> 
> All data object have a record in "objects" which holds the object unique 
> ID and a number that indicates the type. Metainformation about the type 
> is stored in classes and fields tables. A subclass of PersistentObject 
> will have another table which repeats the unique ID in the first field 
> so it can be linked to the record in "objects". A sub-sub-class has 
> another table which also repeats the unique ID in the first field so 
> that all three tables can be joined.

It also seems that you can subclass and don't have to have an extra 
table. I have used this when I wanted to subclass resource for some 
extra functionality but didn't need to store any extra data.

-- 
  -- Matthew Buckett, VLE Developer
  -- Learning Technologies Group, Oxford University Computing Services
  -- Tel: +44 (0)1865 283660 http://www.oucs.ox.ac.uk/ltg/