Modeler:Tutorial/Integrity Checks

Every fact type must have an intra UC

For each fact type, there must be at least one uniqueness constraint that concerns one or more roles of this fact type only.

The N rule must be valid for every nominalized fact type

Every nominalized fact type with n roles only has exactly one uniqueness constraint over all n roles. Generalizations are an exception, therefor this is considered a warning, not an error.

The N-1 rule must be valid for every fact type

If a fact type with n roles has at least one uniqueness constraint on less than n-1 roles, then the fact type is splittable. The n-1 rule-test simply consists of the check that there are no UCs that are too small.

The subtype rule must be valid for every subtype

• There can be no single role totality constraint on the role of a unary fact type.
• Each derivable subtype must have a derivation rule, in which only roles can occur (apart from the role of the subtype itself) from fact types that
  • either are played by one or more of its supertypes
  • or are found in one or more of its supertypes
• In a fact type that is a subtype, all roles have a single role uniqueness constraint. For nominalized subtypes, all object type expressions concern exactly one role.

The alias of an object/fact type must be unique

The alias of a fact type name must be unique amongst all other names.

All object type expressions must be used

Object type expressions are to be used as part of another and finally in an Fact type expression. If no substitution is found for an object type expression, it is found to be invalid.

Non-lexical object types without totality constraints must have a fact type expression

If no totality constraint at all applies to any of the roles played by a certain nominalized fact type, then that fact type must have an existence postulating fact type expression.

The actual population of every fact type must be verbalizable

Object type expressions verbalizing a population is not always sufficient to be verbalizable. Sometimes an additional fact type expression or totality constraint is required to guarantee the population really exists.

Fact types may not contain redundant role combinations

Different fact types may contain sets of roles which have a similar construction. The set of roles and their played by object types may be modeled redundant. If so, it can be resolved by combining these role sets into an object type.

The population should match the value constraints

The values in the population should comply to the value constraints as specified in the relevant label types.

The population should match the totality constraints

If a totality constraint states the population must exist in a different fact type, the example population in the model should comply.

Facts must have at least one sample population

Fact types only exist by expressions and samples. Having no tuples makes validating the expression impossible. Therefor at least one sample must exist.

Roles must have distinct semantic meanings

More than one role can exist in a fact type. Of more than one role in a fact type are played by the same object type, the modeler should either place a role-fix or insert an extra object type. Transformations will fail if this is not handled. (Consider a table after transformation with two columns having the same name.)

Label types must contain a datatype definition

Label types require some data type definition. CaseTalk is able to derive that from the population using a wizard. If not set yet, these label types trigger this warning rule.

Fact types may not contain object types

Fact types with n roles, and n > 2, with a single UC covering N-1 roles, these roles under the UC may be candidate for nominalization.

Binary fact types must have grouping preference

Binary fact types where both roles are under a single uc, or both roles under their own uc, this fact type cannot be automatically grouped during transformation. Therefor to be optimized, at least one role needs a grouping preference.

All generated expressions require validated semantics

In later version of CaseTalk more model (re)factoring functions exist. This may lead to default generated expressions, which are not manually entered by an analyst. To guarantee model quality, these need to be manually verified.

Label types must be used

Label types can only exist if played by at least one role. Label types found in the model without any role played by this label type, the label type should be removed.

Populations must comply with uniqueness constraints

The example population should adhere to the uniqueness constraints applied to the corresponding roles.

Populations must comply with totality constraints

If a tc mandates tuple existence, the population should comply to that. More tuples are required to satisfy this rule.

Population must comply with subset constraints

Subset constraints mandate existence of a population in another fact type. Therefor this rule checks if that is the case within the model and the example population.

Population must comply with datatype

Population values are set to be of a specific data type as specified in the corresponding label type. The values are parsed by CaseTalk to validate they meet the datatype requirements.

External expressions must be supported

It is possible to merge fact expressions from another model file (aka namespace) into another. The expressions are flagged as originating from a different namespace. CaseTalk allows architects to specify which namespaces can be used and which not. This rule simple checks for expressions which were not yet marked as valid merged namespace.

External namespace must cover one version

In elaborate editions of CaseTalk various namespaces and versions of them are allowed to be merged into other models. It should however never occur to merge expressions from two distinct versions of the same namespace.

Value constraints must comply with datatype

The population contains values and value constraints limits the range of these values. Therefor the limits specified must comply to these datatype themselves.

Expression requires soft semantics

Expressions consist of roles and expression parts. If all expression parts in an expression are empty, this warning states the lack of so called soft semantics.

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