This is possible exactly if this evaluation is a homomorphism between the two relational structures.
In other words, every relational structure defines a non-uniform problem, that of telling whether a relation structure is homomorphic to it.
They describe only a relational structure for this information.
This is achieved with the setting up of a relational structure between the meaningful elements of the symbolic system.
The generic structure allows the capture of complex business rules that are difficult to capture using a conventional relational structure.
The construction of these relations define the entities to form a relational structure.
(Patient demographics, for example, are most naturally modeled in one-column-per-attribute, traditional relational structure.)
Databases are designed using hierarchical, network or relational structures; each structure is effective in its own sense.
Conditions equivalent to unit representations of ordered relational structures.
Another (perhaps more natural) generalization of relational structures are general relational structures.