Structure and Syntax of the Design File

This section explains each of the XML elements and attributes in a design file and how they relate to the settings in the Domain Designer. Some elements have been added to show structures that did not appear in the example.

Because certain XML elements correspond to objects in the Domain design, this section refers to XML elements that contain Domain objects such as sets. This is a short-hand description that means the XML elements contain other XML elements that represent the Domain objects. 

These definitions in the design correspond to the first five tabs of the Domain Designer: 




 


Because the elements under resources refer to database objects, they must be externally consistent with the data source intended for this Domain.
 
 

The DomEL Syntax

Various components of a Domain need to compute values based on some expression involving constants, field values, and environment variables. The Domain Expression Language (DomEL) was created to fill this need. Currently, the following features in XML design files are expressed in DomEL:
 

• The "on" and "where" clauses of derived tables
  
  

• The "on" clause of join statements
  
  

• Calculated fields
  
  

• Filter expressions in Domains and Domain topics (equivalent to "where" clauses)
  
  

• The "testProfileAttribute" function
  
  

• Row-level security

A DomEL expression is a shorthand way of writing a complex query. When processing a report based on a Domain, the server interprets DomEL expressions to generate parts of the SQL expression that perform the desired query. Depending on the data policy, either the augmented SQL is passed to the data source, or the server performs a simpler query and applies the DomEL expressions to the full dataset in memory.