Evaluates constraints and determines whether to return false, uncertain, or true, depending on the result.
If any nested constraint returns false, that is the result. Otherwise, if any nested constraint returns uncertain, that is the result. (A comparison of structure concepts with any missing properties will return uncertain; for more details, read about Structure Equivalence.) The result is true if and only if all the nested constraints return true.
Joins can be made conditional by wrapping their constraints in if blocks.
This equivalence block compares two latitude and longitude values in a GeoPoint, specifying values for equivalence and uncertainty.
structure (GeoPoint) {
...
equivalence: join {
fuzzy-numeric-equality (latitude) {
true-tolerance (0.00005)
uncertain-tolerance (0.005)
}
fuzzy-numeric-equality (longitude) {
true-tolerance (0.00005)
uncertain-tolerance (0.005)
}
}
}This block demonstrates a conditional constraint:
equivalence: join {
equal-values (label)
equivalent-values (performer)
equivalent-values (venue)
if (label == 'SingleEvent') {
equivalent-values (events)
}
}| fuzzy-numeric-equality optional | Constraint that relaxes the equivalence threshold for float values (primitive type decimal) |
| fuzzy-string-equality optional | Constraint that relaxes the equivalence threshold for strings (primitive type name) |
| inherit-predicates optional | Inherit the equivalent policy from a parent concept |
| never-equivalent optional | Never set types equal to each other |