Dods Study Diary (v)

from the 5.1final version, the do cache is converted to the datastruct cache. Only those original datastructs are added to the new datastruct cache instead of all do,do only one data (Datastruct object). All transformations are done on this object, the Datastruct object contains the values of the columns of each table, and now do holds two datastruct references.





(1) orginaldata





(2) Data





Orginaldata Saves the original data (read from the database), the data will not be modified until committed, and if the cache exists, the Datastruct object is added to the datastruce cache.





data is only produced when it is modified (copy orginaldata), and if the second datastruct exists, then the Do property "IsDirty" will be set to true, even after some modification The new datastruct holds the same value as the root orginaldata. The do is still dirty, and all there is no way to make the attribute IsDirty from true to false, unless, in the process of committing the transaction, if the transaction is committed, The new datastruct will be transferred to Orginaldata. New





datastruct will be reset to null again, and all properties isdirty to False.





a newly generated do (in memory, not a database) will have only one Datastruct object data, and the Orginaldata data value in Orginaldata is empty before committing.




The
OID and version properties are transferred from do to the Datastruct object.




The newly added properties in
datastruct are:





IsEmpty and DatabaseName




The newly added methods in
datastruct are:





getoid ()





setdatabase (String dbname)





........


      








Dods has the possibility of caching for each table. Possible cache types are: None,lru. and full.





Dods has two levels of caching.





the data cache level. Only one LRU cache,





Query cache level, you can have two query caches (simple and complex types), and these query caches are also LRU caches.





Cache configuration:





similar to the above, also divided into three levels.