Changeset 189 for Doc/Backend/DBInterface.tex

Timestamp:

12/16/11 16:33:07 (13 years ago)

Author:

jkraaijeveld

Message:

Updated .pdf documentation. Model diagram is still outdated though.

File:

• Doc/Backend/DBInterface.tex (modified) (2 diffs)

Doc/Backend/DBInterface.tex

@@ -194 +194 @@
                 and store data through instances of precreated classes. All these classes inherit from a global
                 ResearchToolObject class. A UML class diagram of the model classes can be found in Appendix \ref{models}.  
+                The most important thing to note is that references to other objects are not evaluated immediately. Rather,
+                these classes with references have to override the evaluate() function, which in turn tries to query the
+                database and resolve those UIDs to model objects. This gives us two advantages: initial queries do not scale
+                exponentially because of the 'lazy' evaluation, and the boolean return value notifies us when there exists an
+                incorrect reference. By evaluating before saving an object, we ensure that there cannot exist invalid values in
+                the database.
         \subsection{Connectors}
                 Although the front end developer only uses one general DatabaseInterface, the different files for the different
@@ -200 +206 @@
                 methods are implemented in the baseclass Connector, which should be extended. In every connector,
                 the get() and set() methods are different. A get() method builds the querystring based on the given arguments,
-                then retrieves the data and performs other necessary queries (like retrieving a different object from another
-                file) to ensure the PHP DataModel is comoplete. A set() method has to store the data accordingly. 
+                then retrieves the data and performs other necessary queries (like retrieving a set of fields of unspecified
+                length) to ensure the PHP DataModel is complete. A set() method has to store the data accordingly. 
+
         \subsection{PHPDoc}     
                 PHPDoc for the database classes can be found at