SQL optimisation

• The performances are better if the majority of the Xion expressions can be translated directly into requests SQL ( smaller resultsets, less objects to activate, less memory to allocate, faster sorting algorithms ). However, the capacity of expression of Xion is larger than that of SQL. Consequently, all the Xion requests cannot be entirely translated into SQL.
• Define public attributes. This is bad OO practice but access to this attributes can be directly translated into SQL.
• Do not put intermediary Xion expressions that return collections into variables; directly apply the collection operator to the expression. Putting the result of an expression that returns a collection into a variable will cause the activation in memory of all the objects in the collection, whereas directly applying a collection operator to such an expression will in the best cases only return the result of the execution of the operator.

Content management

• Define public attributes if they must be edited in the content management. The content management is written in Xion and thus cannot bypass the semantics of the language.

PHP tools

• PHP cache and accelerator tools must obey the PHP specifications. Some tools will not be able to run the PHP scripts generated by Netsilon. Netsilon has been successfully tested with Zend Cache version 1.0 and APC version 1.1.0.

Navigation model

• The sequence of web elements linked to a decision center through constraints is ordered. So it is useless to negate in next links the constraint that guards the topmost link.