How SQL Yoga Represents Objects
As of Revolution 4.0 the Revolution engine has no means of creating custom objects. Rather a developer has to rely on one of the existing objects such as stacks, cards, buttons, fields, groups, etc.
While relying on existing Revolution objects works okay for custom GUI objects it is not an appropriate solution for faceless objects (no UI required) such as those used with SQL Yoga.
Representing Objects with Arrays
SQL Yoga addresses the issue of not being to create objects by using Revolution arrays to represent objects. Arrays in Revolution are easy to create and work with and can be multi-dimensional. While not perfect, arrays provide enough flexibility to be an adequate stand-in for real objects.
If you inspect some of the object arrays that SQL Yoga creates you will notice that some keys are prefixed with the @ symbol. The @ symbol designates a special property that the SQL Yoga library uses in order to store certain information about the object.