Some types cannot be constrained, and attempting to do so results in the exception PLS-00566: type name "..." cannot be constrained
being raised.
Noncompliant code example
DECLARE
foo BLOB(42); -- Noncompliant - raises PLS-00566: type name "BLOB" cannot be constrained
BEGIN
NULL;
END;
/
Compliant solution
DECLARE
foo BLOB;
BEGIN
NULL;
END;
/
